/*
- * Project: libFIRM
- * File name: ir/tv/fltcalc.c
- * Purpose:
- * Author:
- * Modified by:
- * Created: 2003
- * CVS-ID: $Id$
- * Copyright: (c) 2003 Universität Karlsruhe
- * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
*/
+/**
+ * @file
+ * @brief tarval floating point calculations
+ * @date 2003
+ * @author Mathias Heil
+ * @version $Id$
+ */
+#include "config.h"
#include "fltcalc.h"
#include "strcalc.h"
+#include "error.h"
-#include <math.h> /* need isnan() and isinf() (will be changed)*/
+#include <math.h>
/* undef some reused constants defined by math.h */
#ifdef NAN
# undef NAN
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
-#include <alloca.h>
+
+#include "xmalloc.h"
+
+#ifndef HAVE_STRTOLD
+#define strtold(s, e) strtod(s, e)
+#endif
+
+#ifdef _MSC_VER
+#include <float.h>
+#define isnan(x) _isnan(x)
+static inline int isinf(double x)
+{
+ return !_finite(x) && !_isnan(x);
+}
+#endif
+
+/** The number of extra precision rounding bits */
+#define ROUNDING_BITS 2
typedef uint32_t UINT32;
-#ifdef HAVE_LONG_DOUBLE
-#ifdef WORDS_BIGENDIAN
typedef union {
- struct {
- UINT32 high;
- UINT32 mid;
- UINT32 low;
- } val;
- volatile long double d;
-} value_t;
+ struct {
+#ifdef WORDS_BIGENDIAN
+ UINT32 high;
#else
-typedef union {
- struct {
- UINT32 low;
- UINT32 mid;
- UINT32 high;
- } val;
- volatile long double d;
-} value_t;
+ UINT32 low;
+#endif
+#ifdef HAVE_LONG_DOUBLE
+ UINT32 mid;
#endif
-#else
#ifdef WORDS_BIGENDIAN
-typedef union {
- struct {
- UINT32 high;
- UINT32 low;
- } val;
- volatile double d;
-} value_t;
+ UINT32 low;
#else
-typedef union {
- struct {
- UINT32 low;
- UINT32 high;
- } val;
- volatile double d;
-} value_t;
+ UINT32 high;
#endif
+ } val;
+#ifdef HAVE_LONG_DOUBLE
+ volatile long double d;
+#else
+ volatile double d;
#endif
+} value_t;
+#define CLEAR_BUFFER(buffer) memset(buffer, 0, calc_buffer_size)
-/********
- * globals
- ********/
-typedef enum {
- NORMAL,
- ZERO,
- SUBNORMAL,
- INF,
- NAN,
-} value_class_t;
-
-typedef struct {
- char exponent_size;
- char mantissa_size;
- value_class_t class;
-} descriptor_t;
-
-#define CLEAR_BUFFER(buffer) memset(buffer, 0, CALC_BUFFER_SIZE)
-
-/* because variable sized structs are impossible, the internal
- * value is represented as a pseudo-struct char array, addressed
- * by macros
- * struct {
- * char sign; // 0 for positive, 1 for negative
- * char exp[VALUE_SIZE];
- * char mant[VALUE_SIZE];
- * descriptor_t desc;
- * };
- */
-#define _sign(a) (((char*)a)[SIGN_POS])
-#define _exp(a) (&((char*)a)[EXPONENT_POS])
-#define _mant(a) (&((char*)a)[MANTISSA_POS])
-#define _desc(a) (*(descriptor_t *)&((char*)a)[DESCRIPTOR_POS])
+/* our floating point value */
+struct fp_value {
+ ieee_descriptor_t desc;
+ char sign;
+ char value[1]; /* exp[value_size] + mant[value_size] */
+};
-#define _save_result(x) memcpy((x), sc_get_buffer(), VALUE_SIZE)
-#define _shift_right(x, y, b) sc_shr((x), (y), VALUE_SIZE*4, 0, (b))
-#define _shift_left(x, y, b) sc_shl((x), (y), VALUE_SIZE*4, 0, (b))
+#define _exp(a) &((a)->value[0])
+#define _mant(a) &((a)->value[value_size])
-#define FC_DEFINE1(code) char* fc_##code(const void *a, void *result) \
- { \
- return _calc((const char*)a, NULL, FC_##code, (char*)result); \
- }
+#define _save_result(x) memcpy((x), sc_get_buffer(), value_size)
+#define _shift_right(x, y, res) sc_shr((x), (y), value_size*4, 0, (res))
+#define _shift_left(x, y, res) sc_shl((x), (y), value_size*4, 0, (res))
-#define FC_DEFINE2(code) char* fc_##code(const void *a, const void *b, void *result) \
- { \
- return _calc((const char*)a, (const char*)b, FC_##code, (char*)result); \
- }
-#define FUNC_PTR(code) fc_##code
-
-#if FLTCALC_DEBUG
+#ifdef FLTCALC_DEBUG
# define DEBUGPRINTF(x) printf x
#else
# define DEBUGPRINTF(x) ((void)0)
#endif
-#if FLTCALC_TRACE_CALC
+#ifdef FLTCALC_TRACE_CALC
# define TRACEPRINTF(x) printf x
#else
# define TRACEPRINTF(x) ((void)0)
#endif
-static char *calc_buffer = NULL;
+/** The immediate precision. */
+static unsigned immediate_prec = 0;
-static fc_rounding_mode_t ROUNDING_MODE;
+/** A temporal buffer. */
+static fp_value *calc_buffer = NULL;
-static int CALC_BUFFER_SIZE;
-static int VALUE_SIZE;
-static int SIGN_POS;
-static int EXPONENT_POS;
-static int MANTISSA_POS;
-static int DESCRIPTOR_POS;
+/** Current rounding mode.*/
+static fc_rounding_mode_t rounding_mode;
+static int calc_buffer_size;
+static int value_size;
static int max_precision;
-/********
- * private functions
- ********/
-#if 0
-static void _fail_char(const char *str, unsigned int len, int pos)
-{
- if (*(str+pos))
- printf("ERROR: Unexpected character '%c'\n", *(str + pos));
- else
- printf("ERROR: Unexpected end of string\n");
- while (len-- && *str) printf("%c", *str++); printf("\n");
- while (pos--) printf(" "); printf("^\n");
- /* the front end has to to check constant strings */
- exit(-1);
-}
-#endif
-
-/* pack machine-like */
-static char* _pack(const char *int_float, char *packed)
-{
- char *shift_val;
- char *temp;
- char *val_buffer;
-
- temp = alloca(VALUE_SIZE);
- shift_val = alloca(VALUE_SIZE);
-
- switch (_desc(int_float).class) {
- case NAN:
- val_buffer = alloca(CALC_BUFFER_SIZE);
- fc_get_qnan(_desc(int_float).exponent_size, _desc(int_float).mantissa_size, val_buffer);
- int_float = val_buffer;
- break;
-
- case INF:
- val_buffer = alloca(CALC_BUFFER_SIZE);
- fc_get_plusinf(_desc(int_float).exponent_size, _desc(int_float).mantissa_size, val_buffer);
- _sign(val_buffer) = _sign(int_float);
- int_float = val_buffer;
- break;
-
- default:
- break;
- }
- /* pack sign */
- sc_val_from_ulong(_sign(int_float), temp);
-
- sc_val_from_ulong(_desc(int_float).exponent_size + _desc(int_float).mantissa_size, NULL);
- _shift_left(temp, sc_get_buffer(), packed);
-
- /* extract exponent */
- sc_val_from_ulong(_desc(int_float).mantissa_size, shift_val);
- _shift_left(_exp(int_float), shift_val, temp);
+/** Exact flag. */
+static int fc_exact = 1;
- sc_or(temp, packed, packed);
-
- /* extract mantissa */
- /* remove 2 rounding bits */
- sc_val_from_ulong(2, shift_val);
- _shift_right(_mant(int_float), shift_val, temp);
-
- /* remove leading 1 (or 0 if denormalized) */
- sc_max_from_bits(_desc(int_float).mantissa_size, 0, shift_val); /* all mantissa bits are 1's */
- sc_and(temp, shift_val, temp);
-
- /* save result */
- sc_or(temp, packed, packed);
-
- return packed;
-}
-
-char* _normalize(const char *in_val, char *out_val, int sticky)
+/** pack machine-like */
+static void *pack(const fp_value *int_float, void *packed)
{
- int hsb;
- char lsb, guard, round, round_dir = 0;
- char *temp;
-
- temp = alloca(VALUE_SIZE);
-
- /* +2: save two rounding bits at the end */
- hsb = 2 + _desc(in_val).mantissa_size - sc_get_highest_set_bit(_mant(in_val)) - 1;
-
- if (in_val != out_val)
- {
- _sign(out_val) = _sign(in_val);
- memcpy(&_desc(out_val), &_desc(in_val), sizeof(descriptor_t));
- }
-
- _desc(out_val).class = NORMAL;
-
- /* mantissa all zeroes, so zero exponent (because of explicit one)*/
- if (hsb == 2 + _desc(in_val).mantissa_size)
- {
- sc_val_from_ulong(0, _exp(out_val));
- hsb = -1;
- }
-
- /* shift the first 1 into the left of the radix point (i.e. hsb == -1) */
- if (hsb < -1)
- {
- /* shift right */
- sc_val_from_ulong(-hsb-1, temp);
-
- _shift_right(_mant(in_val), temp, _mant(out_val));
-
- /* remember if some bits were shifted away */
- if (!sticky) sticky = sc_had_carry();
-
- sc_add(_exp(in_val), temp, _exp(out_val));
- }
- else if (hsb > -1)
- {
- /* shift left */
- sc_val_from_ulong(hsb+1, temp);
-
- _shift_left(_mant(in_val), temp, _mant(out_val));
-
- sc_sub(_exp(in_val), temp, _exp(out_val));
- }
-
- /* check for exponent underflow */
- if (sc_is_negative(_exp(out_val)) || sc_is_zero(_exp(out_val))) {
- DEBUGPRINTF(("Exponent underflow!\n"));
- /* exponent underflow */
- /* shift the mantissa right to have a zero exponent */
- sc_val_from_ulong(1, temp);
- sc_sub(temp, _exp(out_val), NULL);
-
- _shift_right(_mant(out_val), sc_get_buffer(), _mant(out_val));
- if (!sticky) sticky = sc_had_carry();
- /* denormalized means exponent of zero */
- sc_val_from_ulong(0, _exp(out_val));
-
- _desc(out_val).class = SUBNORMAL;
- }
-
- /* perform rounding by adding a value that clears the guard bit and the round bit
- * and either causes a carry to round up or not */
- /* get the last 3 bits of the value */
- lsb = sc_sub_bits(_mant(out_val), _desc(out_val).mantissa_size + 2, 0) & 0x7;
- guard = (lsb&0x2)>>1;
- round = lsb&0x1;
-
- switch (ROUNDING_MODE)
- {
- case FC_TONEAREST:
- /* round to nearest representable value, if in doubt choose the version
- * with lsb == 0 */
- round_dir = guard && (sticky || round || lsb>>2);
- break;
- case FC_TOPOSITIVE:
- /* if positive: round to one if the exact value is bigger, else to zero */
- round_dir = (!_sign(out_val) && (guard || round || sticky));
- break;
- case FC_TONEGATIVE:
- /* if negative: round to one if the exact value is bigger, else to zero */
- round_dir = (_sign(out_val) && (guard || round || sticky));
- break;
- case FC_TOZERO:
- /* always round to 0 (chopping mode) */
- round_dir = 0;
- break;
- }
- DEBUGPRINTF(("Rounding (s%d, l%d, g%d, r%d, s%d) %s\n", _sign(out_val), lsb>>2, guard, round, sticky, (round_dir)?"up":"down"));
-
- if (round_dir == 1)
- {
- guard = (round^guard)<<1;
- lsb = !(round || guard)<<2 | guard | round;
- }
- else
- {
- lsb = -((guard<<1) | round);
- }
-
- /* add the rounded value */
- if (lsb != 0) {
- sc_val_from_long(lsb, temp);
- sc_add(_mant(out_val), temp, _mant(out_val));
- }
-
- /* could have rounded down to zero */
- if (sc_is_zero(_mant(out_val)) && (_desc(out_val).class == SUBNORMAL))
- _desc(out_val).class = ZERO;
-
- /* check for rounding overflow */
- hsb = 2 + _desc(out_val).mantissa_size - sc_get_highest_set_bit(_mant(out_val)) - 1;
- if ((_desc(out_val).class != SUBNORMAL) && (hsb < -1))
- {
- sc_val_from_ulong(1, temp);
- _shift_right(_mant(out_val), temp, _mant(out_val));
-
- sc_add(_exp(out_val), temp, _exp(out_val));
- }
- else if ((_desc(out_val).class == SUBNORMAL) && (hsb == -1))
- {
- /* overflow caused the matissa to be normal again,
- * so adapt the exponent accordingly */
- sc_val_from_ulong(1, temp);
- sc_add(_exp(out_val), temp, _exp(out_val));
-
- _desc(out_val).class = NORMAL;
- }
- /* no further rounding is needed, because rounding overflow means
- * the carry of the original rounding was propagated all the way
- * up to the bit left of the radix point. This implies the bits
- * to the right are all zeros (rounding is +1) */
-
- /* check for exponent overflow */
- sc_val_from_ulong((1 << _desc(out_val).exponent_size) - 1, temp);
- if (sc_comp(_exp(out_val), temp) != -1) {
- DEBUGPRINTF(("Exponent overflow!\n"));
- /* exponent overflow, reaction depends on rounding method:
- *
- * mode | sign of value | result
- *--------------------------------------------------------------
- * TO_NEAREST | + | +inf
- * | - | -inf
- *--------------------------------------------------------------
- * TO_POSITIVE | + | +inf
- * | - | smallest representable value
- *--------------------------------------------------------------
- * TO_NEAGTIVE | + | largest representable value
- * | - | -inf
- *--------------------------------------------------------------
- * TO_ZERO | + | largest representable value
- * | - | smallest representable value
- *--------------------------------------------------------------*/
- if (_sign(out_val) == 0)
- {
- /* value is positive */
- switch (ROUNDING_MODE) {
- case FC_TONEAREST:
- case FC_TOPOSITIVE:
- _desc(out_val).class = INF;
- break;
-
- case FC_TONEGATIVE:
- case FC_TOZERO:
- fc_get_max(_desc(out_val).exponent_size, _desc(out_val).mantissa_size, out_val);
- }
- } else {
- /* value is negative */
- switch (ROUNDING_MODE) {
- case FC_TONEAREST:
- case FC_TONEGATIVE:
- _desc(out_val).class = INF;
- break;
-
- case FC_TOPOSITIVE:
- case FC_TOZERO:
- fc_get_min(_desc(out_val).exponent_size, _desc(out_val).mantissa_size, out_val);
- }
- }
- }
-
- return out_val;
+ char *shift_val;
+ char *temp;
+ fp_value *val_buffer;
+ int pos;
+
+ temp = (char*) alloca(value_size);
+ shift_val = (char*) alloca(value_size);
+
+ switch ((value_class_t)int_float->desc.clss) {
+ case NAN:
+ val_buffer = (fp_value*) alloca(calc_buffer_size);
+ fc_get_qnan(&int_float->desc, val_buffer);
+ int_float = val_buffer;
+ break;
+
+ case INF:
+ val_buffer = (fp_value*) alloca(calc_buffer_size);
+ fc_get_plusinf(&int_float->desc, val_buffer);
+ val_buffer->sign = int_float->sign;
+ int_float = val_buffer;
+ break;
+
+ default:
+ break;
+ }
+ assert(int_float->desc.explicit_one <= 1);
+
+ /* pack sign: move it to the left after exponent AND mantissa */
+ sc_val_from_ulong(int_float->sign, temp);
+
+ pos = int_float->desc.exponent_size + int_float->desc.mantissa_size + int_float->desc.explicit_one;
+ sc_val_from_ulong(pos, NULL);
+ _shift_left(temp, sc_get_buffer(), packed);
+
+ /* pack exponent: move it to the left after mantissa */
+ pos = int_float->desc.mantissa_size + int_float->desc.explicit_one;
+ sc_val_from_ulong(pos, shift_val);
+ _shift_left(_exp(int_float), shift_val, temp);
+
+ /* combine sign|exponent */
+ sc_or(temp, packed, packed);
+
+ /* extract mantissa */
+ /* remove rounding bits */
+ sc_val_from_ulong(ROUNDING_BITS, shift_val);
+ _shift_right(_mant(int_float), shift_val, temp);
+
+ /* remove leading 1 (or 0 if denormalized) */
+ sc_max_from_bits(pos, 0, shift_val); /* all mantissa bits are 1's */
+ sc_and(temp, shift_val, temp);
+
+ /* combine sign|exponent|mantissa */
+ sc_or(temp, packed, packed);
+
+ return packed;
}
-/*
- * calculate a + b, where a is the value with the bigger exponent
+/**
+ * Normalize a fp_value.
+ *
+ * @return non-zero if result is exact
*/
-static char* _add(const char* a, const char* b, char* result)
+static int normalize(const fp_value *in_val, fp_value *out_val, int sticky)
{
- char *temp;
- char *exp_diff;
-
- char sign;
- char sticky;
-
- if (_desc(a).class == NAN) {
- if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
- return result;
- }
- if (_desc(b).class == NAN) {
- if (b != result) memcpy(result, b, CALC_BUFFER_SIZE);
- return result;
- }
-
- /* make sure result has a descriptor */
- if (result != a && result != b)
- memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));
-
- /* determine if this is an addition or subtraction */
- sign = _sign(a) ^ _sign(b);
-
- /* produce nan on inf - inf */
- if (sign && (_desc(a).class == INF) && (_desc(b).class == INF))
- return fc_get_qnan(_desc(a).exponent_size, _desc(b).mantissa_size, result);
-
- temp = alloca(VALUE_SIZE);
- exp_diff = alloca(VALUE_SIZE);
-
- /* get exponent difference */
- sc_sub(_exp(a), _exp(b), exp_diff);
-
- /* initially set sign to be the sign of a, special treatment of subtraction
- * when exponents are equal is required though.
- * Also special care about the sign is needed when the mantissas are equal
- * (+/- 0 ?) */
- if (sign && sc_val_to_long(exp_diff) == 0) {
- switch (sc_comp(_mant(a), _mant(b))) {
- case 1: /* a > b */
- if (_sign(a)) _sign(result) = 1; /* abs(a) is bigger and a is negative */
- else _sign(result) = 0;
- break;
- case 0: /* a == b */
- if (ROUNDING_MODE == FC_TONEGATIVE)
- _sign(result) = 1;
- else
- _sign(result) = 0;
- break;
- case -1: /* a < b */
- if (_sign(b)) _sign(result) = 1; /* abs(b) is bigger and b is negative */
- else _sign(result) = 0;
- break;
- default:
- /* can't be reached */
- break;
- }
- } else {
- _sign(result) = _sign(a);
- }
-
- /* sign has been taken care of, check for special cases */
- if (_desc(a).class == ZERO) {
- if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
- return result;
- }
- if (_desc(b).class == ZERO) {
- if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
- return result;
- }
-
- if (_desc(a).class == INF) {
- if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
- return result;
- }
- if (_desc(b).class == INF) {
- if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
- return result;
- }
-
- /* shift the smaller value to the right to align the radix point */
- /* subnormals have their radix point shifted to the right,
- * take care of this first */
- if ((_desc(b).class == SUBNORMAL) && (_desc(a).class != SUBNORMAL))
- {
- sc_val_from_ulong(1, temp);
- sc_sub(exp_diff, temp, exp_diff);
- }
-
- _shift_right(_mant(b), exp_diff, temp);
- sticky = sc_had_carry();
-
- if (sticky && sign)
- {
- /* if subtracting a little more than the represented value or adding a little
- * more than the represented value to a negative value this, in addition to the
- * still set sticky bit, takes account of the 'little more' */
- char *temp1 = alloca(CALC_BUFFER_SIZE);
- sc_val_from_ulong(1, temp1);
- sc_add(temp, temp1, temp);
- }
-
- if (sign) {
- if (sc_comp(_mant(a), temp) == -1)
- sc_sub(temp, _mant(a), _mant(result));
- else
- sc_sub(_mant(a), temp, _mant(result));
- } else {
- sc_add(_mant(a), temp, _mant(result));
- }
-
- /* _normalize expects a 'normal' radix point, adding two subnormals
- * results in a subnormal radix point -> shifting before normalizing */
- if ((_desc(a).class == SUBNORMAL) && (_desc(b).class == SUBNORMAL))
- {
- sc_val_from_ulong(1, NULL);
- _shift_left(_mant(result), sc_get_buffer(), _mant(result));
- }
-
- /* resulting exponent is the bigger one */
- memmove(_exp(result), _exp(a), VALUE_SIZE);
-
- return _normalize(result, result, sticky);
+ int exact = 1;
+ int hsb;
+ char lsb, guard, round, round_dir = 0;
+ char *temp = (char*) alloca(value_size);
+
+ /* save rounding bits at the end */
+ hsb = ROUNDING_BITS + in_val->desc.mantissa_size - sc_get_highest_set_bit(_mant(in_val)) - 1;
+
+ if (in_val != out_val) {
+ out_val->sign = in_val->sign;
+ memcpy(&out_val->desc, &in_val->desc, sizeof(out_val->desc));
+ }
+
+ out_val->desc.clss = NORMAL;
+
+ /* mantissa all zeros, so zero exponent (because of explicit one) */
+ if (hsb == ROUNDING_BITS + in_val->desc.mantissa_size) {
+ sc_val_from_ulong(0, _exp(out_val));
+ hsb = -1;
+ }
+
+ /* shift the first 1 into the left of the radix point (i.e. hsb == -1) */
+ if (hsb < -1) {
+ /* shift right */
+ sc_val_from_ulong(-hsb-1, temp);
+
+ _shift_right(_mant(in_val), temp, _mant(out_val));
+
+ /* remember if some bits were shifted away */
+ if (sc_had_carry()) {
+ exact = 0;
+ sticky = 1;
+ }
+ sc_add(_exp(in_val), temp, _exp(out_val));
+ } else if (hsb > -1) {
+ /* shift left */
+ sc_val_from_ulong(hsb+1, temp);
+
+ _shift_left(_mant(in_val), temp, _mant(out_val));
+
+ sc_sub(_exp(in_val), temp, _exp(out_val));
+ }
+
+ /* check for exponent underflow */
+ if (sc_is_negative(_exp(out_val)) || sc_is_zero(_exp(out_val))) {
+ DEBUGPRINTF(("Exponent underflow!\n"));
+ /* exponent underflow */
+ /* shift the mantissa right to have a zero exponent */
+ sc_val_from_ulong(1, temp);
+ sc_sub(temp, _exp(out_val), NULL);
+
+ _shift_right(_mant(out_val), sc_get_buffer(), _mant(out_val));
+ if (sc_had_carry()) {
+ exact = 0;
+ sticky = 1;
+ }
+ /* denormalized means exponent of zero */
+ sc_val_from_ulong(0, _exp(out_val));
+
+ out_val->desc.clss = SUBNORMAL;
+ }
+
+ /* perform rounding by adding a value that clears the guard bit and the round bit
+ * and either causes a carry to round up or not */
+ /* get the last 3 bits of the value */
+ lsb = sc_sub_bits(_mant(out_val), out_val->desc.mantissa_size + ROUNDING_BITS, 0) & 0x7;
+ guard = (lsb&0x2)>>1;
+ round = lsb&0x1;
+
+ switch (rounding_mode) {
+ case FC_TONEAREST:
+ /* round to nearest representable value, if in doubt choose the version
+ * with lsb == 0 */
+ round_dir = guard && (sticky || round || lsb>>2);
+ break;
+ case FC_TOPOSITIVE:
+ /* if positive: round to one if the exact value is bigger, else to zero */
+ round_dir = (!out_val->sign && (guard || round || sticky));
+ break;
+ case FC_TONEGATIVE:
+ /* if negative: round to one if the exact value is bigger, else to zero */
+ round_dir = (out_val->sign && (guard || round || sticky));
+ break;
+ case FC_TOZERO:
+ /* always round to 0 (chopping mode) */
+ round_dir = 0;
+ break;
+ }
+ DEBUGPRINTF(("Rounding (s%d, l%d, g%d, r%d, s%d) %s\n", out_val->sign, lsb>>2, guard, round, sticky, (round_dir)?"up":"down"));
+
+ if (round_dir == 1) {
+ guard = (round^guard)<<1;
+ lsb = !(round || guard)<<2 | guard | round;
+ } else {
+ lsb = -((guard<<1) | round);
+ }
+
+ /* add the rounded value */
+ if (lsb != 0) {
+ sc_val_from_long(lsb, temp);
+ sc_add(_mant(out_val), temp, _mant(out_val));
+ exact = 0;
+ }
+
+ /* could have rounded down to zero */
+ if (sc_is_zero(_mant(out_val)) && (out_val->desc.clss == SUBNORMAL))
+ out_val->desc.clss = ZERO;
+
+ /* check for rounding overflow */
+ hsb = ROUNDING_BITS + out_val->desc.mantissa_size - sc_get_highest_set_bit(_mant(out_val)) - 1;
+ if ((out_val->desc.clss != SUBNORMAL) && (hsb < -1)) {
+ sc_val_from_ulong(1, temp);
+ _shift_right(_mant(out_val), temp, _mant(out_val));
+ if (exact && sc_had_carry())
+ exact = 0;
+ sc_add(_exp(out_val), temp, _exp(out_val));
+ } else if ((out_val->desc.clss == SUBNORMAL) && (hsb == -1)) {
+ /* overflow caused the mantissa to be normal again,
+ * so adapt the exponent accordingly */
+ sc_val_from_ulong(1, temp);
+ sc_add(_exp(out_val), temp, _exp(out_val));
+
+ out_val->desc.clss = NORMAL;
+ }
+ /* no further rounding is needed, because rounding overflow means
+ * the carry of the original rounding was propagated all the way
+ * up to the bit left of the radix point. This implies the bits
+ * to the right are all zeros (rounding is +1) */
+
+ /* check for exponent overflow */
+ sc_val_from_ulong((1 << out_val->desc.exponent_size) - 1, temp);
+ if (sc_comp(_exp(out_val), temp) != -1) {
+ DEBUGPRINTF(("Exponent overflow!\n"));
+ /* exponent overflow, reaction depends on rounding method:
+ *
+ * mode | sign of value | result
+ *--------------------------------------------------------------
+ * TO_NEAREST | + | +inf
+ * | - | -inf
+ *--------------------------------------------------------------
+ * TO_POSITIVE | + | +inf
+ * | - | smallest representable value
+ *--------------------------------------------------------------
+ * TO_NEAGTIVE | + | largest representable value
+ * | - | -inf
+ *--------------------------------------------------------------
+ * TO_ZERO | + | largest representable value
+ * | - | smallest representable value
+ *--------------------------------------------------------------*/
+ if (out_val->sign == 0) {
+ /* value is positive */
+ switch (rounding_mode) {
+ case FC_TONEAREST:
+ case FC_TOPOSITIVE:
+ out_val->desc.clss = INF;
+ break;
+
+ case FC_TONEGATIVE:
+ case FC_TOZERO:
+ fc_get_max(&out_val->desc, out_val);
+ }
+ } else {
+ /* value is negative */
+ switch (rounding_mode) {
+ case FC_TONEAREST:
+ case FC_TONEGATIVE:
+ out_val->desc.clss = INF;
+ break;
+
+ case FC_TOPOSITIVE:
+ case FC_TOZERO:
+ fc_get_min(&out_val->desc, out_val);
+ }
+ }
+ }
+ return exact;
}
-static char* _mul(const char* a, const char* b, char* result)
+/**
+ * Operations involving NaN's must return NaN.
+ * They are NOT exact.
+ */
+#define handle_NAN(a, b, result) \
+do { \
+ if (a->desc.clss == NAN) { \
+ if (a != result) memcpy(result, a, calc_buffer_size); \
+ fc_exact = 0; \
+ return; \
+ } \
+ if (b->desc.clss == NAN) { \
+ if (b != result) memcpy(result, b, calc_buffer_size); \
+ fc_exact = 0; \
+ return; \
+ } \
+}while (0)
+
+
+/**
+ * calculate a + b, where a is the value with the bigger exponent
+ */
+static void _fadd(const fp_value *a, const fp_value *b, fp_value *result)
{
- char *temp;
-
- if (_desc(a).class == NAN) {
- if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
- return result;
- }
- if (_desc(b).class == NAN) {
- if (b != result) memcpy(result, b, CALC_BUFFER_SIZE);
- return result;
- }
-
- temp = alloca(VALUE_SIZE);
-
- if (result != a && result != b)
- memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));
-
- _sign(result) = _sign(a) ^ _sign(b);
-
- /* produce nan on 0 * inf */
- if (_desc(a).class == ZERO) {
- if (_desc(b).class == INF)
- fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
- else
- if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
- return result;
- }
- if (_desc(b).class == ZERO) {
- if (_desc(a).class == INF)
- fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
- else
- if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-1);
- return result;
- }
-
- if (_desc(a).class == INF) {
- if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
- return result;
- }
- if (_desc(b).class == INF) {
- if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-1);
- return result;
- }
-
- /* exp = exp(a) + exp(b) - excess */
- sc_add(_exp(a), _exp(b), _exp(result));
-
- sc_val_from_ulong((1<<_desc(a).exponent_size)/2-1, temp);
- sc_sub(_exp(result), temp, _exp(result));
-
- /* mixed normal, subnormal values introduce an error of 1, correct it */
- if ((_desc(a).class == SUBNORMAL) ^ (_desc(b).class == SUBNORMAL))
- {
- sc_val_from_ulong(1, temp);
- sc_add(_exp(result), temp, _exp(result));
- }
-
- sc_mul(_mant(a), _mant(b), _mant(result));
-
- /* realign result: after a multiplication the digits right of the radix
- * point are the sum of the factors' digits after the radix point. As all
- * values are normalized they both have the same amount of these digits,
- * which has to be restored by proper shifting
- * +2 because of the two rounding bits */
- sc_val_from_ulong(2 + _desc(result).mantissa_size, temp);
-
- _shift_right(_mant(result), temp, _mant(result));
-
- return _normalize(result, result, sc_had_carry());
+ char *temp;
+ char *exp_diff;
+
+ char sign, res_sign;
+ char sticky;
+
+ fc_exact = 1;
+
+ handle_NAN(a, b, result);
+
+ /* make sure result has a descriptor */
+ if (result != a && result != b)
+ result->desc = a->desc;
+
+ /* determine if this is an addition or subtraction */
+ sign = a->sign ^ b->sign;
+
+ /* produce NaN on inf - inf */
+ if (sign && (a->desc.clss == INF) && (b->desc.clss == INF)) {
+ fc_exact = 0;
+ fc_get_qnan(&a->desc, result);
+ return;
+ }
+
+ temp = (char*) alloca(value_size);
+ exp_diff = (char*) alloca(value_size);
+
+ /* get exponent difference */
+ sc_sub(_exp(a), _exp(b), exp_diff);
+
+ /* initially set sign to be the sign of a, special treatment of subtraction
+ * when exponents are equal is required though.
+ * Also special care about the sign is needed when the mantissas are equal
+ * (+/- 0 ?) */
+ if (sign && sc_val_to_long(exp_diff) == 0) {
+ switch (sc_comp(_mant(a), _mant(b))) {
+ case 1: /* a > b */
+ res_sign = a->sign; /* abs(a) is bigger and a is negative */
+ break;
+ case 0: /* a == b */
+ res_sign = (rounding_mode == FC_TONEGATIVE);
+ break;
+ case -1: /* a < b */
+ res_sign = b->sign; /* abs(b) is bigger and b is negative */
+ break;
+ default:
+ /* can't be reached */
+ res_sign = 0;
+ break;
+ }
+ }
+ else
+ res_sign = a->sign;
+ result->sign = res_sign;
+
+ /* sign has been taken care of, check for special cases */
+ if (a->desc.clss == ZERO || b->desc.clss == INF) {
+ if (b != result)
+ memcpy(result, b, calc_buffer_size);
+ fc_exact = b->desc.clss == NORMAL;
+ result->sign = res_sign;
+ return;
+ }
+ if (b->desc.clss == ZERO || a->desc.clss == INF) {
+ if (a != result)
+ memcpy(result, a, calc_buffer_size);
+ fc_exact = a->desc.clss == NORMAL;
+ result->sign = res_sign;
+ return;
+ }
+
+ /* shift the smaller value to the right to align the radix point */
+ /* subnormals have their radix point shifted to the right,
+ * take care of this first */
+ if ((b->desc.clss == SUBNORMAL) && (a->desc.clss != SUBNORMAL)) {
+ sc_val_from_ulong(1, temp);
+ sc_sub(exp_diff, temp, exp_diff);
+ }
+
+ _shift_right(_mant(b), exp_diff, temp);
+ sticky = sc_had_carry();
+ fc_exact &= !sticky;
+
+ if (sticky && sign) {
+ /* if subtracting a little more than the represented value or adding a little
+ * more than the represented value to a negative value this, in addition to the
+ * still set sticky bit, takes account of the 'little more' */
+ char *temp1 = (char*) alloca(calc_buffer_size);
+ sc_val_from_ulong(1, temp1);
+ sc_add(temp, temp1, temp);
+ }
+
+ if (sign) {
+ if (sc_comp(_mant(a), temp) == -1)
+ sc_sub(temp, _mant(a), _mant(result));
+ else
+ sc_sub(_mant(a), temp, _mant(result));
+ } else {
+ sc_add(_mant(a), temp, _mant(result));
+ }
+
+ /* _normalize expects a 'normal' radix point, adding two subnormals
+ * results in a subnormal radix point -> shifting before normalizing */
+ if ((a->desc.clss == SUBNORMAL) && (b->desc.clss == SUBNORMAL)) {
+ sc_val_from_ulong(1, NULL);
+ _shift_left(_mant(result), sc_get_buffer(), _mant(result));
+ }
+
+ /* resulting exponent is the bigger one */
+ memmove(_exp(result), _exp(a), value_size);
+
+ fc_exact &= normalize(result, result, sticky);
}
-static char* _div(const char* a, const char* b, char* result)
+/**
+ * calculate a * b
+ */
+static void _fmul(const fp_value *a, const fp_value *b, fp_value *result)
{
- char *temp, *dividend;
-
- if (_desc(a).class == NAN) {
- if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
- return result;
- }
- if (_desc(b).class == NAN) {
- if (b != result) memcpy(result, b, CALC_BUFFER_SIZE);
- return result;
- }
-
- temp = alloca(VALUE_SIZE);
- dividend = alloca(VALUE_SIZE);
-
- if (result != a && result != b)
- memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));
-
- _sign(result) = _sign(a) ^ _sign(b);
-
- /* produce nan on 0/0 and inf/inf */
- if (_desc(a).class == ZERO) {
- if (_desc(b).class == ZERO)
- /* 0/0 -> nan */
- fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
- else
- /* 0/x -> a */
- if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
- return result;
- }
-
- if (_desc(b).class == INF) {
- if (_desc(a).class == INF)
- /* inf/inf -> nan */
- fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
- else {
- /* x/inf -> 0 */
- sc_val_from_ulong(0, NULL);
- _save_result(_exp(result));
- _save_result(_mant(result));
- _desc(result).class = ZERO;
- }
- return result;
- }
-
- if (_desc(a).class == INF) {
- /* inf/x -> inf */
- if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
- return result;
- }
- if (_desc(b).class == ZERO) {
- /* division by zero */
- if (_sign(result))
- fc_get_minusinf(_desc(a).exponent_size, _desc(a).mantissa_size, result);
- else
- fc_get_plusinf(_desc(a).exponent_size, _desc(a).mantissa_size, result);
- return result;
- }
-
- /* exp = exp(a) - exp(b) + excess - 1*/
- sc_sub(_exp(a), _exp(b), _exp(result));
- sc_val_from_ulong((1 << _desc(a).exponent_size)/2-2, temp);
- sc_add(_exp(result), temp, _exp(result));
-
- /* mixed normal, subnormal values introduce an error of 1, correct it */
- if ((_desc(a).class == SUBNORMAL) ^ (_desc(b).class == SUBNORMAL))
- {
- sc_val_from_ulong(1, temp);
- sc_add(_exp(result), temp, _exp(result));
- }
-
- /* mant(res) = mant(a) / 1/2mant(b) */
- /* to gain more bits of precision in the result the dividend could be
- * shifted left, as this operation does not loose bits. This would not
- * fit into the integer precision, but due to the rounding bits (which
- * are always zero because the values are all normalized) the divisor
- * can be shifted right instead to achieve the same result */
- sc_val_from_ulong(2 + _desc(result).mantissa_size, temp);
-
- _shift_left(_mant(a), temp, dividend);
-
- {
- char *divisor = alloca(CALC_BUFFER_SIZE);
- sc_val_from_ulong(1, divisor);
- _shift_right(_mant(b), divisor, divisor);
- sc_div(dividend, divisor, _mant(result));
- }
-
- return _normalize(result, result, sc_had_carry());
+ int sticky;
+ char *temp;
+ char res_sign;
+
+ fc_exact = 1;
+
+ handle_NAN(a, b, result);
+
+ temp = (char*) alloca(value_size);
+
+ if (result != a && result != b)
+ result->desc = a->desc;
+
+ result->sign = res_sign = a->sign ^ b->sign;
+
+ /* produce NaN on 0 * inf */
+ if (a->desc.clss == ZERO) {
+ if (b->desc.clss == INF) {
+ fc_get_qnan(&a->desc, result);
+ fc_exact = 0;
+ } else {
+ if (a != result)
+ memcpy(result, a, calc_buffer_size);
+ result->sign = res_sign;
+ }
+ return;
+ }
+ if (b->desc.clss == ZERO) {
+ if (a->desc.clss == INF) {
+ fc_get_qnan(&a->desc, result);
+ fc_exact = 0;
+ } else {
+ if (b != result)
+ memcpy(result, b, calc_buffer_size);
+ result->sign = res_sign;
+ }
+ return;
+ }
+
+ if (a->desc.clss == INF) {
+ fc_exact = 0;
+ if (a != result)
+ memcpy(result, a, calc_buffer_size);
+ result->sign = res_sign;
+ return;
+ }
+ if (b->desc.clss == INF) {
+ fc_exact = 0;
+ if (b != result)
+ memcpy(result, b, calc_buffer_size);
+ result->sign = res_sign;
+ return;
+ }
+
+ /* exp = exp(a) + exp(b) - excess */
+ sc_add(_exp(a), _exp(b), _exp(result));
+
+ sc_val_from_ulong((1 << (a->desc.exponent_size - 1)) - 1, temp);
+ sc_sub(_exp(result), temp, _exp(result));
+
+ /* mixed normal, subnormal values introduce an error of 1, correct it */
+ if ((a->desc.clss == SUBNORMAL) ^ (b->desc.clss == SUBNORMAL)) {
+ sc_val_from_ulong(1, temp);
+ sc_add(_exp(result), temp, _exp(result));
+ }
+
+ sc_mul(_mant(a), _mant(b), _mant(result));
+
+ /* realign result: after a multiplication the digits right of the radix
+ * point are the sum of the factors' digits after the radix point. As all
+ * values are normalized they both have the same amount of these digits,
+ * which has to be restored by proper shifting
+ * because of the rounding bits */
+ sc_val_from_ulong(ROUNDING_BITS + result->desc.mantissa_size, temp);
+
+ _shift_right(_mant(result), temp, _mant(result));
+ sticky = sc_had_carry();
+ fc_exact &= !sticky;
+
+ fc_exact &= normalize(result, result, sticky);
}
-void _power_of_ten(int exp, descriptor_t *desc, char *result)
+/**
+ * calculate a / b
+ */
+static void _fdiv(const fp_value *a, const fp_value *b, fp_value *result)
{
- char *build;
- char *temp;
-
- /* positive sign */
- _sign(result) = 0;
-
- /* set new descriptor (else result is supposed to already have one) */
- if (desc != NULL)
- memcpy(&_desc(result), desc, sizeof(descriptor_t));
-
- build = alloca(VALUE_SIZE);
- temp = alloca(VALUE_SIZE);
-
- sc_val_from_ulong((1 << _desc(result).exponent_size)/2-1, _exp(result));
-
- if (exp > 0)
- {
- /* temp is value of ten now */
- sc_val_from_ulong(10, NULL);
- _save_result(temp);
-
- for (exp--; exp > 0; exp--) {
- _save_result(build);
- sc_mul(build, temp, NULL);
- }
- _save_result(build);
-
- /* temp is amount of leftshift needed to put the value left of the radix point */
- sc_val_from_ulong(_desc(result).mantissa_size + 2, temp);
-
- _shift_left(build, temp, _mant(result));
-
- _normalize(result, result, 0);
- }
+ int sticky;
+ char *temp, *dividend;
+ char res_sign;
+
+ fc_exact = 1;
+
+ handle_NAN(a, b, result);
+
+ temp = (char*) alloca(value_size);
+ dividend = (char*) alloca(value_size);
+
+ if (result != a && result != b)
+ result->desc = a->desc;
+
+ result->sign = res_sign = a->sign ^ b->sign;
+
+ /* produce NAN on 0/0 and inf/inf */
+ if (a->desc.clss == ZERO) {
+ if (b->desc.clss == ZERO) {
+ /* 0/0 -> NaN */
+ fc_get_qnan(&a->desc, result);
+ fc_exact = 0;
+ } else {
+ /* 0/x -> a */
+ if (a != result)
+ memcpy(result, a, calc_buffer_size);
+ result->sign = res_sign;
+ }
+ return;
+ }
+
+ if (b->desc.clss == INF) {
+ fc_exact = 0;
+ if (a->desc.clss == INF) {
+ /* inf/inf -> NaN */
+ fc_get_qnan(&a->desc, result);
+ } else {
+ /* x/inf -> 0 */
+ sc_val_from_ulong(0, NULL);
+ _save_result(_exp(result));
+ _save_result(_mant(result));
+ result->desc.clss = ZERO;
+ }
+ return;
+ }
+
+ if (a->desc.clss == INF) {
+ fc_exact = 0;
+ /* inf/x -> inf */
+ if (a != result)
+ memcpy(result, a, calc_buffer_size);
+ result->sign = res_sign;
+ return;
+ }
+ if (b->desc.clss == ZERO) {
+ fc_exact = 0;
+ /* division by zero */
+ if (result->sign)
+ fc_get_minusinf(&a->desc, result);
+ else
+ fc_get_plusinf(&a->desc, result);
+ return;
+ }
+
+ /* exp = exp(a) - exp(b) + excess - 1*/
+ sc_sub(_exp(a), _exp(b), _exp(result));
+ sc_val_from_ulong((1 << (a->desc.exponent_size - 1)) - 2, temp);
+ sc_add(_exp(result), temp, _exp(result));
+
+ /* mixed normal, subnormal values introduce an error of 1, correct it */
+ if ((a->desc.clss == SUBNORMAL) ^ (b->desc.clss == SUBNORMAL)) {
+ sc_val_from_ulong(1, temp);
+ sc_add(_exp(result), temp, _exp(result));
+ }
+
+ /* mant(res) = mant(a) / 1/2mant(b) */
+ /* to gain more bits of precision in the result the dividend could be
+ * shifted left, as this operation does not loose bits. This would not
+ * fit into the integer precision, but due to the rounding bits (which
+ * are always zero because the values are all normalized) the divisor
+ * can be shifted right instead to achieve the same result */
+ sc_val_from_ulong(ROUNDING_BITS + result->desc.mantissa_size, temp);
+
+ _shift_left(_mant(a), temp, dividend);
+
+ {
+ char *divisor = (char*) alloca(calc_buffer_size);
+ sc_val_from_ulong(1, divisor);
+ _shift_right(_mant(b), divisor, divisor);
+ sc_div(dividend, divisor, _mant(result));
+ sticky = sc_had_carry();
+ fc_exact &= !sticky;
+ }
+
+ fc_exact &= normalize(result, result, sticky);
}
-static char* _trunc(const char *a, char *result)
+#if 0
+static void _power_of_ten(int exp, ieee_descriptor_t *desc, char *result)
{
- /* when exponent == 0 all bits left of the radix point
- * are the integral part of the value. For 15bit exp_size
- * this would require a leftshift of max. 16383 bits which
- * is too much.
- * But it is enough to ensure that no bit right of the radix
- * point remains set. This restricts the interesting
- * exponents to the interval [0, mant_size-1].
- * Outside this interval the truncated value is either 0 or
- * it is are already truncated */
-
- int exp_bias, exp_val;
- char *temp;
-
- temp = alloca(VALUE_SIZE);
+ char *build;
+ char *temp;
- if (a != result)
- memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));
+ /* positive sign */
+ result->sign = 0;
- exp_bias = (1<<_desc(a).exponent_size)/2-1;
- exp_val = sc_val_to_long(_exp(a)) - exp_bias;
+ /* set new descriptor (else result is supposed to already have one) */
+ if (desc != NULL)
+ result->desc = *desc;
- if (exp_val < 0) {
- sc_val_from_ulong(0, NULL);
- _save_result(_exp(result));
- _save_result(_mant(result));
- _desc(result).class = ZERO;
+ build = alloca(value_size);
+ temp = alloca(value_size);
- return result;
- }
+ sc_val_from_ulong((1 << (result->desc.exponent_size - 1)) - 1, _exp(result));
- if (exp_val > _desc(a).mantissa_size) {
- if (a != result)
- memcpy(result, a, CALC_BUFFER_SIZE);
+ if (exp > 0) {
+ /* temp is value of ten now */
+ sc_val_from_ulong(10, NULL);
+ _save_result(temp);
- return result;
- }
+ for (exp--; exp > 0; exp--) {
+ _save_result(build);
+ sc_mul(build, temp, NULL);
+ }
+ _save_result(build);
- /* set up a proper mask to delete all bits right of the
- * radix point if the mantissa had been shifted until exp == 0 */
- sc_max_from_bits(1 + exp_val, 0, temp);
- sc_val_from_long(_desc(a).mantissa_size - exp_val + 2, NULL);
- _shift_left(temp, sc_get_buffer(), temp);
+ /* temp is amount of left shift needed to put the value left of the radix point */
+ sc_val_from_ulong(result->desc.mantissa_size + ROUNDING_BITS, temp);
- /* and the mask and return the result */
- sc_and(_mant(a), temp, _mant(result));
+ _shift_left(build, temp, _mant(result));
- if (a != result) memcpy(_exp(result), _exp(a), VALUE_SIZE);
-
- return result;
+ _normalize(result, result, 0);
+ }
}
-
-/*
- * This does value sanity checking(or should do it), sets up any prerequisites,
- * calls the proper internal functions, clears up and returns
- * the result */
-char* _calc(const char *a, const char *b, int opcode, char *result)
-{
- char *temp;
-#ifdef FLTCALC_TRACE_CALC
- char *buffer;
-
- buffer = alloca(100);
#endif
- if (result == NULL) result = calc_buffer;
-
- TRACEPRINTF(("%s ", fc_print(a, buffer, 100, FC_PACKED)));
- switch (opcode)
- {
- case FC_add:
- /* make the value with the bigger exponent the first one */
- TRACEPRINTF(("+ %s ", fc_print(b, buffer, 100, FC_PACKED)));
- if (sc_comp(_exp(a), _exp(b)) == -1)
- _add(b, a, result);
- else
- _add(a, b, result);
- break;
- case FC_sub:
- TRACEPRINTF(("- %s ", fc_print(b, buffer, 100, FC_PACKED)));
- temp = alloca(CALC_BUFFER_SIZE);
- memcpy(temp, b, CALC_BUFFER_SIZE);
- _sign(temp) = !_sign(b);
- if (sc_comp(_exp(a), _exp(temp)) == -1)
- _add(temp, a, result);
- else
- _add(a, temp, result);
- break;
- case FC_mul:
- TRACEPRINTF(("* %s ", fc_print(b, buffer, 100, FC_PACKED)));
- _mul(a, b, result);
- break;
- case FC_div:
- TRACEPRINTF(("/ %s ", fc_print(b, buffer, 100, FC_PACKED)));
- _div(a, b, result);
- break;
- case FC_neg:
- TRACEPRINTF(("negated "));
- if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
- _sign(result) = !_sign(a);
- break;
- case FC_int:
- _trunc(a, result);
- break;
- case FC_rnd:
- break;
- }
-
- TRACEPRINTF(("= %s\n", fc_print(result, buffer, 100, FC_PACKED)));
- return result;
+/**
+ * Truncate the fractional part away.
+ *
+ * This does not clip to any integer range.
+ */
+static void _trunc(const fp_value *a, fp_value *result)
+{
+ /*
+ * When exponent == 0 all bits left of the radix point
+ * are the integral part of the value. For 15bit exp_size
+ * this would require a left shift of max. 16383 bits which
+ * is too much.
+ * But it is enough to ensure that no bit right of the radix
+ * point remains set. This restricts the interesting
+ * exponents to the interval [0, mant_size-1].
+ * Outside this interval the truncated value is either 0 or
+ * it does not have fractional parts.
+ */
+
+ int exp_bias, exp_val;
+ char *temp;
+
+ /* fixme: can be exact */
+ fc_exact = 0;
+
+ temp = (char*) alloca(value_size);
+
+ if (a != result)
+ result->desc = a->desc;
+
+ exp_bias = (1 << (a->desc.exponent_size - 1)) - 1;
+ exp_val = sc_val_to_long(_exp(a)) - exp_bias;
+
+ if (exp_val < 0) {
+ sc_val_from_ulong(0, NULL);
+ _save_result(_exp(result));
+ _save_result(_mant(result));
+ result->desc.clss = ZERO;
+
+ return;
+ }
+
+ if (exp_val > a->desc.mantissa_size) {
+ if (a != result)
+ memcpy(result, a, calc_buffer_size);
+
+ return;
+ }
+
+ /* set up a proper mask to delete all bits right of the
+ * radix point if the mantissa had been shifted until exp == 0 */
+ sc_max_from_bits(1 + exp_val, 0, temp);
+ sc_val_from_long(a->desc.mantissa_size - exp_val + 2, NULL);
+ _shift_left(temp, sc_get_buffer(), temp);
+
+ /* and the mask and return the result */
+ sc_and(_mant(a), temp, _mant(result));
+
+ if (a != result) {
+ memcpy(_exp(result), _exp(a), value_size);
+ result->sign = a->sign;
+ }
}
/********
********/
const void *fc_get_buffer(void)
{
- return calc_buffer;
+ return calc_buffer;
}
-const int fc_get_buffer_length(void)
+int fc_get_buffer_length(void)
{
- return CALC_BUFFER_SIZE;
+ return calc_buffer_size;
}
-char* fc_val_from_str(const char *str, unsigned int len, char exp_size, char mant_size, char *result)
+void *fc_val_from_str(const char *str, size_t len, const ieee_descriptor_t *desc, void *result)
{
-#if 0
- enum {
- START,
- LEFT_OF_DOT,
- RIGHT_OF_DOT,
- EXP_START,
- EXPONENT,
- END
- };
-
- char exp_sign;
- int exp_int, hsb, state;
-
- const char *old_str;
-
- int pos;
- char *mant_str, *exp_val, *power_val;
-
- if (result == NULL) result = calc_buffer;
-
- exp_val = alloca(VALUE_SIZE);
- power_val = alloca(CALC_BUFFER_SIZE);
- mant_str = alloca((len)?(len):(strlen(str)));
-
- _desc(result).exponent_size = exp_size;
- _desc(result).mantissa_size = mant_size;
- _desc(result).class = NORMAL;
-
- old_str = str;
- pos = 0;
- exp_int = 0;
- state = START;
-
- while (len == 0 || str-old_str < len)
- {
- switch (state) {
- case START:
- switch (*str) {
- case '+':
- _sign(result) = 0;
- state = LEFT_OF_DOT;
- str++;
- break;
-
- case '-':
- _sign(result) = 1;
- state = LEFT_OF_DOT;
- str++;
- break;
-
- case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
- _sign(result) = 0;
- state = LEFT_OF_DOT;
- break;
-
- case '.':
- _sign(result) = 0;
- state = RIGHT_OF_DOT;
- str++;
- break;
-
- case 'n':
- case 'N':
- case 'i':
- case 'I':
- break;
-
- default:
- _fail_char(old_str, len, str - old_str);
- }
- break;
-
- case LEFT_OF_DOT:
- switch (*str) {
- case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
- mant_str[pos++] = *(str++);
- break;
-
- case '.':
- state = RIGHT_OF_DOT;
- str++;
- break;
-
- case 'e':
- case 'E':
- state = EXP_START;
- str++;
- break;
-
- case '\0':
- mant_str[pos] = '\0';
- goto done;
-
- default:
- _fail_char(old_str, len, str - old_str);
- }
- break;
-
- case RIGHT_OF_DOT:
- switch (*str) {
- case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
- mant_str[pos++] = *(str++);
- exp_int++;
- break;
-
- case 'e':
- case 'E':
- state = EXP_START;
- str++;
- break;
-
- case '\0':
- mant_str[pos] = '\0';
- goto done;
-
- default:
- _fail_char(old_str, len, str - old_str);
- }
- break;
-
- case EXP_START:
- switch (*str) {
- case '-':
- exp_sign = 1;
- /* fall through */
- case '+':
- if (*(str-1) != 'e' && *(str-1) != 'E') _fail_char(old_str, len, str - old_str);
- str++;
- break;
-
- case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
- mant_str[pos] = '\0';
- pos = 1;
- str++;
- state = EXPONENT;
- break;
-
- default:
- _fail_char(old_str, len, str - old_str);
- }
- break;
-
- case EXPONENT:
- switch (*str) {
- case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
- pos++;
- str++;
- break;
-
- case '\0': goto done;
-
- default:
- _fail_char(old_str, len, str - old_str);
- }
- }
- } // switch(state)
-
-done:
- sc_val_from_str(mant_str, strlen(mant_str), _mant(result));
-
- /* shift to put value left of radix point */
- sc_val_from_ulong(mant_size + 2, exp_val);
-
- _shift_left(_mant(result), exp_val, _mant(result));
-
- sc_val_from_ulong((1 << exp_size)/2-1, _exp(result));
-
- _normalize(result, result, 0);
-
- if (state == EXPONENT) {
- exp_int -= atoi(str-pos);
- }
-
- _power_of_ten(exp_int, &_desc(result), power_val);
-
- _div(result, power_val, result);
-
- return result;
-#else
-
- /* XXX excuse of an implementation to make things work */
- LLDBL val;
-#ifdef HAVE_LONG_DOUBLE
- val = strtold(str, NULL);
-#else
- val = strtod(str, NULL);
-#endif
-
- DEBUGPRINTF(("val_from_str(%s)\n", str));
- return fc_val_from_float(val, exp_size, mant_size, result);
-#endif
+ char *buffer;
+
+ /* XXX excuse of an implementation to make things work */
+ LLDBL val;
+ fp_value *tmp = (fp_value*) alloca(calc_buffer_size);
+ ieee_descriptor_t tmp_desc;
+
+ buffer = (char*) alloca(len+1);
+ memcpy(buffer, str, len);
+ buffer[len] = '\0';
+ val = strtold(buffer, NULL);
+
+ DEBUGPRINTF(("val_from_str(%s)\n", str));
+ tmp_desc.exponent_size = 15;
+ tmp_desc.mantissa_size = 63;
+ tmp_desc.explicit_one = 1;
+ tmp_desc.clss = NORMAL;
+ fc_val_from_ieee754(val, &tmp_desc, tmp);
+
+ return fc_cast(tmp, desc, (fp_value*) result);
}
-char* fc_val_from_float(LLDBL l, char exp_size, char mant_size, char* result)
+fp_value *fc_val_from_ieee754(LLDBL l, const ieee_descriptor_t *desc, fp_value *result)
{
- char *temp;
- int bias_res, bias_val, mant_val;
- value_t srcval;
- UINT32 sign, exponent, mantissa0, mantissa1;
+ char *temp;
+ int bias_res, bias_val, mant_val;
+ value_t srcval;
+ char sign;
+ UINT32 exponent, mantissa0, mantissa1;
- srcval.d = l;
- bias_res = ((1<<exp_size)/2-1);
+ srcval.d = l;
+ bias_res = ((1 << (desc->exponent_size - 1)) - 1);
#ifdef HAVE_LONG_DOUBLE
- mant_val = 64;
- bias_val = 0x3fff;
- sign = (srcval.val.high & 0x00008000) != 0;
- exponent = (srcval.val.high & 0x00007FFF) ;
- mantissa0 = srcval.val.mid;
- mantissa1 = srcval.val.low;
+ mant_val = 63;
+ bias_val = 0x3fff;
+ sign = (srcval.val.high & 0x00008000) != 0;
+ exponent = (srcval.val.high & 0x00007FFF) ;
+ mantissa0 = srcval.val.mid;
+ mantissa1 = srcval.val.low;
#else /* no long double */
- mant_val = 52;
- bias_val = 0x3ff;
- sign = (srcval.val.high & 0x80000000) != 0;
- exponent = (srcval.val.high & 0x7FF00000) >> 20;
- mantissa0 = srcval.val.high & 0x000FFFFF;
- mantissa1 = srcval.val.low;
+ mant_val = 52;
+ bias_val = 0x3ff;
+ sign = (srcval.val.high & 0x80000000) != 0;
+ exponent = (srcval.val.high & 0x7FF00000) >> 20;
+ mantissa0 = srcval.val.high & 0x000FFFFF;
+ mantissa1 = srcval.val.low;
#endif
#ifdef HAVE_LONG_DOUBLE
- TRACEPRINTF(("val_from_float(%.8X%.8X%.8X)\n", ((int*)&l)[2], ((int*)&l)[1], ((int*)&l)[0]));//srcval.val.high, srcval.val.mid, srcval.val.low));
- DEBUGPRINTF(("(%d-%.4X-%.8X%.8X)\n", sign, exponent, mantissa0, mantissa1));
-#else
- TRACEPRINTF(("val_from_float(%.8X%.8X)\n", srcval.val.high, srcval.val.low));
- DEBUGPRINTF(("(%d-%.3X-%.5X%.8X)\n", sign, exponent, mantissa0, mantissa1));
-#endif
-
- if (result == NULL) result = calc_buffer;
- temp = alloca(VALUE_SIZE);
-
- _desc(result).exponent_size = exp_size;
- _desc(result).mantissa_size = mant_size;
-
- /* extract sign */
- _sign(result) = sign;
-
- /* sign and flag suffice to identify nan or inf, no exponent/mantissa
- * encoding is needed. the function can return immediately in these cases */
- if (isnan(l)) {
- _desc(result).class = NAN;
- TRACEPRINTF(("val_from_float resulted in NAN\n"));
- return result;
- }
- else if (isinf(l)) {
- _desc(result).class = INF;
- TRACEPRINTF(("val_from_float resulted in %sINF\n", (_sign(result)==1)?"-":""));
- return result;
- }
-
- /* build exponent, because input and output exponent and mantissa sizes may differ
- * this looks more complicated than it is: unbiased input exponent + output bias,
- * minus the mantissa difference which is added again later when the output float
- * becomes normalized */
-#ifdef HAVE_EXPLICIT_ONE
- sc_val_from_long((exponent-bias_val+bias_res)-(mant_val-mant_size-1), _exp(result));
+ TRACEPRINTF(("val_from_float(%.8X%.8X%.8X)\n", srcval.val.high & 0xFFFF, srcval.val.mid, srcval.val.low));
+ DEBUGPRINTF(("(%d-%.4X-%.8X%.8X)\n", sign, exponent, mantissa0, mantissa1));
#else
- sc_val_from_long((exponent-bias_val+bias_res)-(mant_val-mant_size), _exp(result));
+ TRACEPRINTF(("val_from_float(%.8X%.8X)\n", srcval.val.high, srcval.val.low));
+ DEBUGPRINTF(("(%d-%.3X-%.5X%.8X)\n", sign, exponent, mantissa0, mantissa1));
#endif
- /* build mantissa representation */
-#ifndef HAVE_EXPLICIT_ONE
- if (exponent != 0)
- {
- /* insert the hidden bit */
- sc_val_from_ulong(1, temp);
- sc_val_from_ulong(mant_val + 2, NULL);
- _shift_left(temp, sc_get_buffer(), NULL);
- }
- else
-#endif
- {
- sc_val_from_ulong(0, NULL);
- }
-
- _save_result(_mant(result));
-
- /* bits from the upper word */
- sc_val_from_ulong(mantissa0, temp);
- sc_val_from_ulong(34, NULL);
- _shift_left(temp, sc_get_buffer(), temp);
- sc_or(_mant(result), temp, _mant(result));
-
- /* bits from the lower word */
- sc_val_from_ulong(mantissa1, temp);
- sc_val_from_ulong(2, NULL);
- _shift_left(temp, sc_get_buffer(), temp);
- sc_or(_mant(result), temp, _mant(result));
-
- /* _normalize expects the radix point to be normal, so shift mantissa of subnormal
- * origin one to the left */
- if (exponent == 0)
- {
- sc_val_from_ulong(1, NULL);
- _shift_left(_mant(result), sc_get_buffer(), _mant(result));
- }
-
- _normalize(result, result, 0);
-
- TRACEPRINTF(("val_from_float results in %s\n", fc_print(result, temp, CALC_BUFFER_SIZE, FC_PACKED)));
-
- return result;
+ if (result == NULL) result = calc_buffer;
+ temp = (char*) alloca(value_size);
+
+ /* CLEAR the buffer, else some bits might be uninitialized */
+ memset(result, 0, fc_get_buffer_length());
+
+ result->desc.exponent_size = desc->exponent_size;
+ result->desc.mantissa_size = desc->mantissa_size;
+ result->desc.explicit_one = desc->explicit_one;
+
+ /* extract sign */
+ result->sign = sign;
+
+ /* sign and flag suffice to identify NaN or inf, no exponent/mantissa
+ * encoding is needed. the function can return immediately in these cases */
+ if (isnan(l)) {
+ result->desc.clss = NAN;
+ TRACEPRINTF(("val_from_float resulted in NAN\n"));
+ return result;
+ } else if (isinf(l)) {
+ result->desc.clss = INF;
+ TRACEPRINTF(("val_from_float resulted in %sINF\n", (result->sign == 1) ? "-" : ""));
+ return result;
+ }
+
+ /* build exponent, because input and output exponent and mantissa sizes may differ
+ * this looks more complicated than it is: unbiased input exponent + output bias,
+ * minus the mantissa difference which is added again later when the output float
+ * becomes normalized */
+ sc_val_from_long((exponent - bias_val + bias_res) - (mant_val - desc->mantissa_size), _exp(result));
+
+ /* build mantissa representation */
+ if (exponent != 0) {
+ /* insert the hidden bit */
+ sc_val_from_ulong(1, temp);
+ sc_val_from_ulong(mant_val + ROUNDING_BITS, NULL);
+ _shift_left(temp, sc_get_buffer(), NULL);
+ }
+ else {
+ sc_val_from_ulong(0, NULL);
+ }
+
+ _save_result(_mant(result));
+
+ /* bits from the upper word */
+ sc_val_from_ulong(mantissa0, temp);
+ sc_val_from_ulong(34, NULL);
+ _shift_left(temp, sc_get_buffer(), temp);
+ sc_or(_mant(result), temp, _mant(result));
+
+ /* bits from the lower word */
+ sc_val_from_ulong(mantissa1, temp);
+ sc_val_from_ulong(ROUNDING_BITS, NULL);
+ _shift_left(temp, sc_get_buffer(), temp);
+ sc_or(_mant(result), temp, _mant(result));
+
+ /* _normalize expects the radix point to be normal, so shift mantissa of subnormal
+ * origin one to the left */
+ if (exponent == 0) {
+ sc_val_from_ulong(1, NULL);
+ _shift_left(_mant(result), sc_get_buffer(), _mant(result));
+ }
+
+ normalize(result, result, 0);
+
+ TRACEPRINTF(("val_from_float results in %s\n", fc_print(result, temp, calc_buffer_size, FC_PACKED)));
+
+ return result;
}
-LLDBL fc_val_to_float(const void *val)
+LLDBL fc_val_to_ieee754(const fp_value *val)
{
- const char *value;
- char *temp = NULL;
+ fp_value *value;
+ fp_value *temp = NULL;
- int byte_offset;
+ int byte_offset;
- UINT32 sign;
- UINT32 exponent;
- UINT32 mantissa0;
- UINT32 mantissa1;
+ UINT32 sign;
+ UINT32 exponent;
+ UINT32 mantissa0;
+ UINT32 mantissa1;
- value_t buildval;
+ value_t buildval;
+ ieee_descriptor_t desc;
+ unsigned mantissa_size;
#ifdef HAVE_LONG_DOUBLE
- char result_exponent = 15;
- char result_mantissa = 64;
-#else
- char result_exponent = 11;
- char result_mantissa = 52;
-#endif
-
- temp = alloca(CALC_BUFFER_SIZE);
-#ifdef HAVE_EXPLICIT_ONE
- value = fc_cast(val, result_exponent, result_mantissa-1, temp);
+ desc.exponent_size = 15;
+ desc.mantissa_size = 63;
+ desc.explicit_one = 1;
+ desc.clss = NORMAL;
#else
- value = fc_cast(val, result_exponent, result_mantissa, temp);
+ desc.exponent_size = 11;
+ desc.mantissa_size = 52;
+ desc.explicit_one = 0;
+ desc.clss = NORMAL;
#endif
+ mantissa_size = desc.mantissa_size + desc.explicit_one;
- sign = _sign(value);
+ temp = (fp_value*) alloca(calc_buffer_size);
+ value = fc_cast(val, &desc, temp);
- /* @@@ long double exponent is 15bit, so the use of sc_val_to_long should not
- * lead to wrong results */
- exponent = sc_val_to_long(_exp(value)) ;
+ sign = value->sign;
- sc_val_from_ulong(2, NULL);
- _shift_right(_mant(value), sc_get_buffer(), _mant(value));
+ /* @@@ long double exponent is 15bit, so the use of sc_val_to_long should not
+ * lead to wrong results */
+ exponent = sc_val_to_long(_exp(value)) ;
- mantissa0 = 0;
- mantissa1 = 0;
+ sc_val_from_ulong(ROUNDING_BITS, NULL);
+ _shift_right(_mant(value), sc_get_buffer(), _mant(value));
- for (byte_offset = 0; byte_offset < 4; byte_offset++)
- mantissa1 |= sc_sub_bits(_mant(value), result_mantissa, byte_offset) << (byte_offset<<3);
+ mantissa0 = 0;
+ mantissa1 = 0;
- for (; (byte_offset<<3) < result_mantissa; byte_offset++)
- mantissa0 |= sc_sub_bits(_mant(value), result_mantissa, byte_offset) << ((byte_offset-4)<<3);
+ for (byte_offset = 0; byte_offset < 4; byte_offset++)
+ mantissa1 |= sc_sub_bits(_mant(value), mantissa_size, byte_offset) << (byte_offset << 3);
-#ifndef HAVE_LONG_DOUBLE
- mantissa0 &= 0x000FFFFF; /* get rid of garbage */
-#endif
+ for (; (byte_offset<<3) < desc.mantissa_size; byte_offset++)
+ mantissa0 |= sc_sub_bits(_mant(value), mantissa_size, byte_offset) << ((byte_offset - 4) << 3);
#ifdef HAVE_LONG_DOUBLE
- buildval.val.high = sign << 15;
- buildval.val.high |= exponent;
- buildval.val.mid = mantissa0;
- buildval.val.low = mantissa1;
+ buildval.val.high = sign << 15;
+ buildval.val.high |= exponent;
+ buildval.val.mid = mantissa0;
+ buildval.val.low = mantissa1;
#else /* no long double */
- buildval.val.high = sign << 31;
- buildval.val.high |= exponent << 20;
- buildval.val.high |= mantissa0;
- buildval.val.low = mantissa1;
+ mantissa0 &= 0x000FFFFF; /* get rid of garbage */
+ buildval.val.high = sign << 31;
+ buildval.val.high |= exponent << 20;
+ buildval.val.high |= mantissa0;
+ buildval.val.low = mantissa1;
#endif
- TRACEPRINTF(("val_to_float: %d-%x-%x%x\n", sign, exponent, mantissa0, mantissa1));
- return buildval.d;
+ TRACEPRINTF(("val_to_float: %d-%x-%x%x\n", sign, exponent, mantissa0, mantissa1));
+ return buildval.d;
}
-char* fc_cast(const void *val, char exp_size, char mant_size, char *result)
+fp_value *fc_cast(const fp_value *value, const ieee_descriptor_t *desc, fp_value *result)
{
- const char *value = (const char*) val;
- char *temp;
- int exp_offset, val_bias, res_bias;
-
- if (result == NULL) result = calc_buffer;
- temp = alloca(VALUE_SIZE);
-
- if (_desc(value).exponent_size == exp_size && _desc(value).mantissa_size == mant_size)
- {
- if (value != result) memcpy(result, value, CALC_BUFFER_SIZE);
- return result;
- }
-
- /* set the descriptor of the new value */
- _desc(result).exponent_size = exp_size;
- _desc(result).mantissa_size = mant_size;
- _desc(result).class = _desc(value).class;
-
- _sign(result) = _sign(value);
-
- /* when the mantissa sizes differ normalizing has to shift to align it.
- * this would change the exponent, which is unwanted. So calculate this
- * offset and add it */
- val_bias = (1<<_desc(value).exponent_size)/2-1;
- res_bias = (1<<exp_size)/2-1;
-
- exp_offset = (res_bias - val_bias) - (_desc(value).mantissa_size - mant_size);
- sc_val_from_long(exp_offset, temp);
- sc_add(_exp(value), temp, _exp(result));
-
- /* _normalize expects normalized radix point */
- if (_desc(val).class == SUBNORMAL) {
- sc_val_from_ulong(1, NULL);
- _shift_left(_mant(val), sc_get_buffer(), _mant(result));
- } else if (value != result) {
- memcpy(_mant(result), _mant(value), VALUE_SIZE);
- } else {
- memmove(_mant(result), _mant(value), VALUE_SIZE);
- }
-
- _normalize(result, result, 0);
- TRACEPRINTF(("Cast results in %s\n", fc_print(result, temp, VALUE_SIZE, FC_PACKED)));
- return result;
+ char *temp;
+ int exp_offset, val_bias, res_bias;
+
+ if (result == NULL) result = calc_buffer;
+ temp = (char*) alloca(value_size);
+
+ if (value->desc.exponent_size == desc->exponent_size &&
+ value->desc.mantissa_size == desc->mantissa_size &&
+ value->desc.explicit_one == desc->explicit_one) {
+ if (value != result)
+ memcpy(result, value, calc_buffer_size);
+ return result;
+ }
+
+ if (value->desc.clss == NAN) {
+ if (sc_get_highest_set_bit(_mant(value)) == value->desc.mantissa_size + 1)
+ return fc_get_qnan(desc, result);
+ else
+ return fc_get_snan(desc, result);
+ }
+ else if (value->desc.clss == INF) {
+ if (value->sign == 0)
+ return fc_get_plusinf(desc, result);
+ else
+ return fc_get_minusinf(desc, result);
+ }
+
+ /* set the descriptor of the new value */
+ result->desc.exponent_size = desc->exponent_size;
+ result->desc.mantissa_size = desc->mantissa_size;
+ result->desc.explicit_one = desc->explicit_one;
+ result->desc.clss = value->desc.clss;
+
+ result->sign = value->sign;
+
+ /* when the mantissa sizes differ normalizing has to shift to align it.
+ * this would change the exponent, which is unwanted. So calculate this
+ * offset and add it */
+ val_bias = (1 << (value->desc.exponent_size - 1)) - 1;
+ res_bias = (1 << (desc->exponent_size - 1)) - 1;
+
+ exp_offset = (res_bias - val_bias) - (value->desc.mantissa_size - desc->mantissa_size);
+ sc_val_from_long(exp_offset, temp);
+ sc_add(_exp(value), temp, _exp(result));
+
+ /* _normalize expects normalized radix point */
+ if (value->desc.clss == SUBNORMAL) {
+ sc_val_from_ulong(1, NULL);
+ _shift_left(_mant(value), sc_get_buffer(), _mant(result));
+ } else if (value != result) {
+ memcpy(_mant(result), _mant(value), value_size);
+ } else {
+ memmove(_mant(result), _mant(value), value_size);
+ }
+
+ normalize(result, result, 0);
+ TRACEPRINTF(("Cast results in %s\n", fc_print(result, temp, value_size, FC_PACKED)));
+ return result;
}
-char* fc_get_max(unsigned int exponent_size, unsigned int mantissa_size, char* result)
+fp_value *fc_get_max(const ieee_descriptor_t *desc, fp_value *result)
{
- if (result == NULL) result = calc_buffer;
+ if (result == NULL) result = calc_buffer;
- _desc(result).exponent_size = exponent_size;
- _desc(result).mantissa_size = mantissa_size;
- _desc(result).class = NORMAL;
+ result->desc.exponent_size = desc->exponent_size;
+ result->desc.mantissa_size = desc->mantissa_size;
+ result->desc.explicit_one = desc->explicit_one;
+ result->desc.clss = NORMAL;
- _sign(result) = 0;
+ result->sign = 0;
- sc_val_from_ulong((1<<exponent_size) - 2, _exp(result));
+ sc_val_from_ulong((1 << desc->exponent_size) - 2, _exp(result));
- sc_max_from_bits(mantissa_size + 1, 0, _mant(result));
- sc_val_from_ulong(2, NULL);
- _shift_left(_mant(result), sc_get_buffer(), _mant(result));
+ sc_max_from_bits(desc->mantissa_size + 1, 0, _mant(result));
+ sc_val_from_ulong(ROUNDING_BITS, NULL);
+ _shift_left(_mant(result), sc_get_buffer(), _mant(result));
- return result;
+ return result;
}
-char* fc_get_min(unsigned int exponent_size, unsigned int mantissa_size, char *result)
+fp_value *fc_get_min(const ieee_descriptor_t *desc, fp_value *result)
{
- if (result == NULL) result = calc_buffer;
+ if (result == NULL) result = calc_buffer;
- fc_get_max(exponent_size, mantissa_size, result);
- _sign(result) = 1;
+ fc_get_max(desc, result);
+ result->sign = 1;
- return result;
+ return result;
}
-char* fc_get_snan(unsigned int exponent_size, unsigned int mantissa_size, char *result)
+fp_value *fc_get_snan(const ieee_descriptor_t *desc, fp_value *result)
{
- if (result == NULL) result = calc_buffer;
+ if (result == NULL) result = calc_buffer;
- _desc(result).exponent_size = exponent_size;
- _desc(result).mantissa_size = mantissa_size;
- _desc(result).class = NAN;
+ result->desc.exponent_size = desc->exponent_size;
+ result->desc.mantissa_size = desc->mantissa_size;
+ result->desc.explicit_one = desc->explicit_one;
+ result->desc.clss = NAN;
- _sign(result) = 0;
+ result->sign = 0;
- sc_val_from_ulong((1<<exponent_size)-1, _exp(result));
+ sc_val_from_ulong((1 << desc->exponent_size) - 1, _exp(result));
- /* signalling nan has non-zero mantissa with msb not set */
- sc_val_from_ulong(1, _mant(result));
+ /* signaling NaN has non-zero mantissa with msb not set */
+ sc_val_from_ulong(1, _mant(result));
- return result;
+ return result;
}
-char* fc_get_qnan(unsigned int exponent_size, unsigned int mantissa_size, char *result)
+fp_value *fc_get_qnan(const ieee_descriptor_t *desc, fp_value *result)
{
- if (result == NULL) result = calc_buffer;
+ if (result == NULL) result = calc_buffer;
- _desc(result).exponent_size = exponent_size;
- _desc(result).mantissa_size = mantissa_size;
- _desc(result).class = NAN;
+ result->desc.exponent_size = desc->exponent_size;
+ result->desc.mantissa_size = desc->mantissa_size;
+ result->desc.explicit_one = desc->explicit_one;
+ result->desc.clss = NAN;
- _sign(result) = 0;
+ result->sign = 0;
- sc_val_from_ulong((1<<exponent_size)-1, _exp(result));
+ sc_val_from_ulong((1 << desc->exponent_size) - 1, _exp(result));
- /* quiet nan has the msb of the mantissa set, so shift one there */
- sc_val_from_ulong(1, _mant(result));
- /* mantissa_size >+< 1 because of two extra rounding bits */
- sc_val_from_ulong(mantissa_size + 1, NULL);
- _shift_left(_mant(result), sc_get_buffer(), _mant(result));
+ /* quiet NaN has the msb of the mantissa set, so shift one there */
+ sc_val_from_ulong(1, _mant(result));
+ /* mantissa_size >+< 1 because of two extra rounding bits */
+ sc_val_from_ulong(desc->mantissa_size + 1, NULL);
+ _shift_left(_mant(result), sc_get_buffer(), _mant(result));
- return result;
+ return result;
}
-char* fc_get_plusinf(unsigned int exponent_size, unsigned int mantissa_size, char *result)
+fp_value *fc_get_plusinf(const ieee_descriptor_t *desc, fp_value *result)
{
- if (result == NULL) result = calc_buffer;
+ char *mant;
+
+ if (result == NULL) result = calc_buffer;
- _desc(result).exponent_size = exponent_size;
- _desc(result).mantissa_size = mantissa_size;
- _desc(result).class = NORMAL;
+ result->desc.exponent_size = desc->exponent_size;
+ result->desc.mantissa_size = desc->mantissa_size;
+ result->desc.explicit_one = desc->explicit_one;
+ result->desc.clss = INF;
- _sign(result) = 0;
+ result->sign = 0;
- sc_val_from_ulong((1<<exponent_size)-1, _exp(result));
+ sc_val_from_ulong((1 << desc->exponent_size) - 1, _exp(result));
- sc_val_from_ulong(0, _mant(result));
+ mant = _mant(result);
+ sc_val_from_ulong(0, mant);
+ if (desc->explicit_one) {
+ sc_set_bit_at(mant, result->desc.mantissa_size + ROUNDING_BITS);
+ }
- return result;
+ return result;
}
-char* fc_get_minusinf(unsigned int exponent_size, unsigned int mantissa_size, char *result)
+fp_value *fc_get_minusinf(const ieee_descriptor_t *desc, fp_value *result)
{
- if (result == NULL) result = calc_buffer;
+ if (result == NULL) result = calc_buffer;
- fc_get_plusinf(exponent_size, mantissa_size, result);
- _sign(result) = 1;
+ fc_get_plusinf(desc, result);
+ result->sign = 1;
- return result;
+ return result;
}
-int fc_comp(const void *a, const void *b)
+int fc_comp(const fp_value *val_a, const fp_value *val_b)
{
- const char *val_a = (const char*)a;
- const char *val_b = (const char*)b;
-
- /* unordered */
- if (_desc(val_a).class == NAN || _desc(val_b).class == NAN) return 2;
- /* zero is equal independent of sign */
- if ((_desc(val_a).class == ZERO) && (_desc(val_b).class == ZERO)) return 0;
- /* different signs make compare easy */
- if (_sign(val_a) != _sign(val_b)) return (_sign(val_a)==0)?(1):(-1);
- /* both infinity means equality */
- if ((_desc(val_a).class == INF) && (_desc(val_b).class == INF)) return 0;
- /* infinity is bigger than the rest */
- if (_desc(val_a).class == INF) return _sign(val_a)?(-1):(1);
- if (_desc(val_b).class == INF) return _sign(val_b)?(1):(-1);
-
- switch (sc_comp(_exp(val_a), _exp(val_b))) {
- case -1:
- return -1;
- case 1:
- return 1;
- case 0:
- return sc_comp(_mant(val_a), _mant(val_b));
- default:
- return 2;
- }
+ int mul = 1;
+
+ /*
+ * shortcut: if both values are identical, they are either
+ * Unordered if NaN or equal
+ */
+ if (val_a == val_b)
+ return val_a->desc.clss == NAN ? 2 : 0;
+
+ /* unordered if one is a NaN */
+ if (val_a->desc.clss == NAN || val_b->desc.clss == NAN)
+ return 2;
+
+ /* zero is equal independent of sign */
+ if ((val_a->desc.clss == ZERO) && (val_b->desc.clss == ZERO))
+ return 0;
+
+ /* different signs make compare easy */
+ if (val_a->sign != val_b->sign)
+ return (val_a->sign == 0) ? (1) : (-1);
+
+ mul = val_a->sign ? -1 : 1;
+
+ /* both infinity means equality */
+ if ((val_a->desc.clss == INF) && (val_b->desc.clss == INF))
+ return 0;
+
+ /* infinity is bigger than the rest */
+ if (val_a->desc.clss == INF)
+ return 1 * mul;
+ if (val_b->desc.clss == INF)
+ return -1 * mul;
+
+ /* check first exponent, that mantissa if equal */
+ switch (sc_comp(_exp(val_a), _exp(val_b))) {
+ case -1:
+ return -1 * mul;
+ case 1:
+ return 1 * mul;
+ case 0:
+ return sc_comp(_mant(val_a), _mant(val_b)) * mul;
+ default:
+ return 2;
+ }
}
-int fc_is_zero(const void *a)
+int fc_is_zero(const fp_value *a)
{
- return _desc((const char*)a).class == ZERO;
+ return a->desc.clss == ZERO;
}
-int fc_is_negative(const void *a)
+int fc_is_negative(const fp_value *a)
{
- return _sign((const char*)a);
+ return a->sign;
}
-int fc_is_inf(const void *a)
+int fc_is_inf(const fp_value *a)
{
- return _desc(a).class == INF;
+ return a->desc.clss == INF;
}
-int fc_is_nan(const void *a)
+int fc_is_nan(const fp_value *a)
{
- return _desc(a).class == NAN;
+ return a->desc.clss == NAN;
}
-int fc_is_subnormal(const void *a)
+int fc_is_subnormal(const fp_value *a)
{
- return _desc(a).class == SUBNORMAL;
+ return a->desc.clss == SUBNORMAL;
}
-char *fc_print(const void *a, char *buf, int buflen, unsigned base)
+char *fc_print(const fp_value *val, char *buf, int buflen, unsigned base)
{
- const char *val;
- char *mul_1;
-
- val = (const char*)a;
-
- mul_1 = alloca(CALC_BUFFER_SIZE);
-
- switch (base) {
- case FC_DEC:
- switch (_desc(val).class) {
- case INF:
- if (buflen >= 8+_sign(val)) sprintf(buf, "%sINFINITY", _sign(val)?"-":"");
- else snprintf(buf, buflen, "%sINF", _sign(val)?"-":NULL);
- break;
- case NAN:
- snprintf(buf, buflen, "NAN");
- break;
- case ZERO:
- snprintf(buf, buflen, "0.0");
- break;
- default:
- /* XXX to be implemented */
+ char *mul_1;
+ LLDBL flt_val;
+
+ mul_1 = (char*) alloca(calc_buffer_size);
+
+ switch (base) {
+ case FC_DEC:
+ switch ((value_class_t)val->desc.clss) {
+ case INF:
+ snprintf(buf, buflen, "%cINF", val->sign ? '-' : '+');
+ break;
+ case NAN:
+ snprintf(buf, buflen, "NaN");
+ break;
+ case ZERO:
+ snprintf(buf, buflen, "0.0");
+ break;
+ default:
+ flt_val = fc_val_to_ieee754(val);
#ifdef HAVE_LONG_DOUBLE
- /* XXX 30 is arbitrary */
- snprintf(buf, buflen, "%.30LE", fc_val_to_float(val));
+ /* XXX 30 is arbitrary */
+ snprintf(buf, buflen, "%.30LE", flt_val);
#else
- snprintf(buf, buflen, "%.18E", fc_val_to_float(val));
+ snprintf(buf, buflen, "%.18E", flt_val);
#endif
- }
- break;
-
- case FC_HEX:
- switch (_desc(val).class) {
- case INF:
- if (buflen >= 8+_sign(val)) sprintf(buf, "%sINFINITY", _sign(val)?"-":"");
- else snprintf(buf, buflen, "%sINF", _sign(val)?"-":NULL);
- break;
- case NAN:
- snprintf(buf, buflen, "NAN");
- break;
- case ZERO:
- snprintf(buf, buflen, "0.0");
- break;
- default:
+ }
+ break;
+
+ case FC_HEX:
+ switch ((value_class_t)val->desc.clss) {
+ case INF:
+ snprintf(buf, buflen, "%cINF", val->sign ? '-' : '+');
+ break;
+ case NAN:
+ snprintf(buf, buflen, "NAN");
+ break;
+ case ZERO:
+ snprintf(buf, buflen, "0.0");
+ break;
+ default:
+ flt_val = fc_val_to_ieee754(val);
#ifdef HAVE_LONG_DOUBLE
- snprintf(buf, buflen, "%LA", fc_val_to_float(val));
+ snprintf(buf, buflen, "%LA", flt_val);
#else
- snprintf(buf, buflen, "%A", fc_val_to_float(val));
+ snprintf(buf, buflen, "%A", flt_val);
#endif
- }
- break;
-
- case FC_PACKED:
- default:
- snprintf(buf, buflen, "%s", sc_print(_pack(val, mul_1), VALUE_SIZE*4, SC_HEX));
- break;
- }
- return buf;
+ }
+ break;
+
+ case FC_PACKED:
+ default:
+ snprintf(buf, buflen, "%s", sc_print(pack(val, mul_1), value_size*4, SC_HEX, 0));
+ buf[buflen - 1] = '\0';
+ break;
+ }
+ return buf;
}
-unsigned char fc_sub_bits(const void *value, unsigned num_bits, unsigned byte_ofs)
+unsigned char fc_sub_bits(const fp_value *value, unsigned num_bits, unsigned byte_ofs)
{
- /* this is used to cache the packed version of the value */
- static char *pack = NULL;
+ /* this is used to cache the packed version of the value */
+ static char *packed_value = NULL;
+
+ if (packed_value == NULL) packed_value = XMALLOCN(char, value_size);
- if (pack == NULL) pack = malloc(VALUE_SIZE);
+ if (value != NULL)
+ pack(value, packed_value);
- if (value != NULL)
- _pack((const char*)value, pack);
+ return sc_sub_bits(packed_value, num_bits, byte_ofs);
+}
- return sc_sub_bits(pack, num_bits, byte_ofs);
+/* Returns non-zero if the mantissa is zero, i.e. 1.0Exxx */
+int fc_zero_mantissa(const fp_value *value)
+{
+ return sc_get_lowest_set_bit(_mant(value)) == ROUNDING_BITS + value->desc.mantissa_size;
+}
+
+/* Returns the exponent of a value. */
+int fc_get_exponent(const fp_value *value)
+{
+ int exp_bias = (1 << (value->desc.exponent_size - 1)) - 1;
+ return sc_val_to_long(_exp(value)) - exp_bias;
+}
+
+/* Return non-zero if a given value can be converted lossless into another precision */
+int fc_can_lossless_conv_to(const fp_value *value, const ieee_descriptor_t *desc)
+{
+ int v;
+ int exp_bias;
+
+ /* handle some special cases first */
+ switch (value->desc.clss) {
+ case ZERO:
+ case INF:
+ case NAN:
+ return 1;
+ default:
+ break;
+ }
+
+ /* check if the exponent can be encoded: note, 0 and all ones are reserved for the exponent */
+ exp_bias = (1 << (desc->exponent_size - 1)) - 1;
+ v = fc_get_exponent(value) + exp_bias;
+ if (0 < v && v < (1 << desc->exponent_size) - 1) {
+ /* exponent can be encoded, now check the mantissa */
+ v = value->desc.mantissa_size + ROUNDING_BITS - sc_get_lowest_set_bit(_mant(value));
+ return v <= desc->mantissa_size;
+ }
+ return 0;
}
+
fc_rounding_mode_t fc_set_rounding_mode(fc_rounding_mode_t mode)
{
- if (mode == FC_TONEAREST || mode == FC_TOPOSITIVE || mode == FC_TONEGATIVE || mode == FC_TOZERO)
- ROUNDING_MODE = mode;
+ if (mode == FC_TONEAREST || mode == FC_TOPOSITIVE || mode == FC_TONEGATIVE || mode == FC_TOZERO)
+ rounding_mode = mode;
- return ROUNDING_MODE;
+ return rounding_mode;
}
fc_rounding_mode_t fc_get_rounding_mode(void)
{
- return ROUNDING_MODE;
+ return rounding_mode;
}
void init_fltcalc(int precision)
{
- if (calc_buffer == NULL) {
- /* does nothing if already init */
- if (precision == 0) precision = FC_DEFAULT_PRECISION;
-
- init_strcalc(precision + 4);
-
- /* needs additionally two bits to round, a bit as explicit 1., and one for
- * addition overflow */
- max_precision = sc_get_precision() - 4;
- if (max_precision < precision)
- printf("WARING: not enough precision available, using %d\n", max_precision);
-
- ROUNDING_MODE = FC_TONEAREST;
- VALUE_SIZE = sc_get_buffer_length();
- SIGN_POS = 0;
- EXPONENT_POS = SIGN_POS + sizeof(char);
- MANTISSA_POS = EXPONENT_POS + VALUE_SIZE;
- DESCRIPTOR_POS = MANTISSA_POS + VALUE_SIZE;
- CALC_BUFFER_SIZE = DESCRIPTOR_POS + sizeof(descriptor_t);
-
- calc_buffer = malloc(CALC_BUFFER_SIZE);
- DEBUGPRINTF(("init fltcalc:\n\tVALUE_SIZE = %d\n\tSIGN_POS = %d\n\tEXPONENT_POS = %d\n\tMANTISSA_POS = %d\n\tDESCRIPTOR_POS = %d\n\tCALC_BUFFER_SIZE = %d\n\tcalc_buffer = %p\n\n", VALUE_SIZE, SIGN_POS, EXPONENT_POS, MANTISSA_POS, DESCRIPTOR_POS, CALC_BUFFER_SIZE, calc_buffer));
+ if (calc_buffer == NULL) {
+ /* does nothing if already init */
+ if (precision == 0) precision = FC_DEFAULT_PRECISION;
+
+ init_strcalc(precision + 2 + ROUNDING_BITS);
+
+ /* needs additionally rounding bits, one bit as explicit 1., and one for
+ * addition overflow */
+ max_precision = sc_get_precision() - (2 + ROUNDING_BITS);
+ if (max_precision < precision)
+ printf("WARNING: not enough precision available, using %d\n", max_precision);
+
+ rounding_mode = FC_TONEAREST;
+ value_size = sc_get_buffer_length();
+ calc_buffer_size = sizeof(fp_value) + 2*value_size - 1;
+
+ calc_buffer = (fp_value*) xmalloc(calc_buffer_size);
+ memset(calc_buffer, 0, calc_buffer_size);
+ DEBUGPRINTF(("init fltcalc:\n\tVALUE_SIZE = %d\ntCALC_BUFFER_SIZE = %d\n\tcalc_buffer = %p\n\n", value_size, calc_buffer_size, calc_buffer));
#ifdef HAVE_LONG_DOUBLE
- DEBUGPRINTF(("\tUsing long double (1-15-64) interface\n"));
+ DEBUGPRINTF(("\tUsing long double (1-15-64) interface\n"));
#else
- DEBUGPRINTF(("\tUsing double (1-11-52) interface\n"));
+ DEBUGPRINTF(("\tUsing double (1-11-52) interface\n"));
#endif
#ifdef WORDS_BIGENDIAN
- DEBUGPRINTF(("\tWord order is big endian\n\n"));
+ DEBUGPRINTF(("\tWord order is big endian\n\n"));
#else
- DEBUGPRINTF(("\tWord order is little endian\n\n"));
+ DEBUGPRINTF(("\tWord order is little endian\n\n"));
#endif
- }
+ }
}
+void finish_fltcalc (void)
+{
+ free(calc_buffer); calc_buffer = NULL;
+}
+
+#ifdef FLTCALC_TRACE_CALC
+static char buffer[100];
+#endif
+
/* definition of interface functions */
-FC_DEFINE2(add)
-FC_DEFINE2(sub)
-FC_DEFINE2(mul)
-FC_DEFINE2(div)
-FC_DEFINE1(neg)
-FC_DEFINE1(int)
-FC_DEFINE1(rnd)
+fp_value *fc_add(const fp_value *a, const fp_value *b, fp_value *result)
+{
+ if (result == NULL) result = calc_buffer;
+
+ TRACEPRINTF(("%s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
+ TRACEPRINTF(("+ %s ", fc_print(b, buffer, sizeof(buffer), FC_PACKED)));
+
+ /* make the value with the bigger exponent the first one */
+ if (sc_comp(_exp(a), _exp(b)) == -1)
+ _fadd(b, a, result);
+ else
+ _fadd(a, b, result);
+
+ TRACEPRINTF(("= %s\n", fc_print(result, buffer, sizeof(buffer), FC_PACKED)));
+ return result;
+}
+
+fp_value *fc_sub(const fp_value *a, const fp_value *b, fp_value *result)
+{
+ fp_value *temp;
+
+ if (result == NULL) result = calc_buffer;
+
+ TRACEPRINTF(("%s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
+ TRACEPRINTF(("- %s ", fc_print(b, buffer, sizeof(buffer), FC_PACKED)));
+
+ temp = (fp_value*) alloca(calc_buffer_size);
+ memcpy(temp, b, calc_buffer_size);
+ temp->sign = !b->sign;
+ if (sc_comp(_exp(a), _exp(temp)) == -1)
+ _fadd(temp, a, result);
+ else
+ _fadd(a, temp, result);
+
+ TRACEPRINTF(("= %s\n", fc_print(result, buffer, sizeof(buffer), FC_PACKED)));
+ return result;
+}
+
+fp_value *fc_mul(const fp_value *a, const fp_value *b, fp_value *result)
+{
+ if (result == NULL) result = calc_buffer;
+
+ TRACEPRINTF(("%s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
+ TRACEPRINTF(("* %s ", fc_print(b, buffer, sizeof(buffer), FC_PACKED)));
+
+ _fmul(a, b, result);
+
+ TRACEPRINTF(("= %s\n", fc_print(result, buffer, sizeof(buffer), FC_PACKED)));
+ return result;
+}
+
+fp_value *fc_div(const fp_value *a, const fp_value *b, fp_value *result)
+{
+ if (result == NULL) result = calc_buffer;
+
+ TRACEPRINTF(("%s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
+ TRACEPRINTF(("/ %s ", fc_print(b, buffer, sizeof(buffer), FC_PACKED)));
+
+ _fdiv(a, b, result);
+
+ TRACEPRINTF(("= %s\n", fc_print(result, buffer, sizeof(buffer), FC_PACKED)));
+ return result;
+}
+
+fp_value *fc_neg(const fp_value *a, fp_value *result)
+{
+ if (result == NULL) result = calc_buffer;
+
+ TRACEPRINTF(("- %s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
+
+ if (a != result)
+ memcpy(result, a, calc_buffer_size);
+ result->sign = !a->sign;
+
+ TRACEPRINTF(("= %s\n", fc_print(result, buffer, sizeof(buffer), FC_PACKED)));
+ return result;
+}
+
+fp_value *fc_int(const fp_value *a, fp_value *result)
+{
+ if (result == NULL) result = calc_buffer;
+
+ TRACEPRINTF(("%s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
+ TRACEPRINTF(("truncated to integer "));
+
+ _trunc(a, result);
+
+ TRACEPRINTF(("= %s\n", fc_print(result, buffer, sizeof(buffer), FC_PACKED)));
+ return result;
+}
+
+fp_value *fc_rnd(const fp_value *a, fp_value *result)
+{
+ if (result == NULL) result = calc_buffer;
+
+ (void) a;
+ TRACEPRINTF(("%s ", fc_print(a, buffer, sizeof(buffer), FC_PACKED)));
+ TRACEPRINTF(("rounded to integer "));
+
+ panic("fc_rnd() not yet implemented");
+}
+
+/*
+ * convert a floating point value into an sc value ...
+ */
+int fc_flt2int(const fp_value *a, void *result, ir_mode *dst_mode)
+{
+ if (a->desc.clss == NORMAL) {
+ int exp_bias = (1 << (a->desc.exponent_size - 1)) - 1;
+ int exp_val = sc_val_to_long(_exp(a)) - exp_bias;
+ int shift, highest;
+ int mantissa_size;
+ int tgt_bits;
+
+ if (a->sign && !mode_is_signed(dst_mode)) {
+ /* FIXME: for now we cannot convert this */
+ return 0;
+ }
+
+ tgt_bits = get_mode_size_bits(dst_mode);
+ if (mode_is_signed(dst_mode))
+ --tgt_bits;
+
+ assert(exp_val >= 0 && "floating point value not integral before fc_flt2int() call");
+ mantissa_size = a->desc.mantissa_size + ROUNDING_BITS;
+ shift = exp_val - mantissa_size;
+
+ if (tgt_bits < mantissa_size + 1)
+ tgt_bits = mantissa_size + 1;
+ if (shift > 0) {
+ sc_shlI(_mant(a), shift, tgt_bits, 0, result);
+ } else {
+ sc_shrI(_mant(a), -shift, tgt_bits, 0, result);
+ }
+
+ /* check for overflow */
+ highest = sc_get_highest_set_bit(result);
+
+ if (mode_is_signed(dst_mode)) {
+ if (highest == sc_get_lowest_set_bit(result)) {
+ /* need extra test for MIN_INT */
+ if (highest >= (int) get_mode_size_bits(dst_mode)) {
+ /* FIXME: handle overflow */
+ return 0;
+ }
+ } else {
+ if (highest >= (int) get_mode_size_bits(dst_mode) - 1) {
+ /* FIXME: handle overflow */
+ return 0;
+ }
+ }
+ } else {
+ if (highest >= (int) get_mode_size_bits(dst_mode)) {
+ /* FIXME: handle overflow */
+ return 0;
+ }
+ }
+
+ if (a->sign)
+ sc_neg(result, result);
+
+ return 1;
+ }
+ else if (a->desc.clss == ZERO) {
+ sc_zero(result);
+ return 1;
+ }
+ return 0;
+}
+
+
+unsigned fc_set_immediate_precision(unsigned bits)
+{
+ unsigned old = immediate_prec;
+
+ immediate_prec = bits;
+ return old;
+}
+
+int fc_is_exact(void)
+{
+ return fc_exact;
+}
projects / libfirm / blobdiff