/*
- * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
+ * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
*
* This file is part of libFirm.
*
#include "xmalloc.h"
+/** The number of extra precesion rounding bits */
+#define ROUNDING_BITS 2
+
typedef uint32_t UINT32;
#ifdef HAVE_LONG_DOUBLE
sc_or(temp, packed, packed);
/* extract mantissa */
- /* remove 2 rounding bits */
- sc_val_from_ulong(2, shift_val);
+ /* 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) */
char lsb, guard, round, round_dir = 0;
char *temp = alloca(value_size);
- /* +2: save two rounding bits at the end */
- hsb = 2 + in_val->desc.mantissa_size - sc_get_highest_set_bit(_mant(in_val)) - 1;
+ /* 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;
out_val->desc.clss = NORMAL;
/* mantissa all zeros, so zero exponent (because of explicit one) */
- if (hsb == 2 + in_val->desc.mantissa_size) {
+ if (hsb == ROUNDING_BITS + in_val->desc.mantissa_size) {
sc_val_from_ulong(0, _exp(out_val));
hsb = -1;
}
/* 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 + 2, 0) & 0x7;
+ lsb = sc_sub_bits(_mant(out_val), out_val->desc.mantissa_size + ROUNDING_BITS, 0) & 0x7;
guard = (lsb&0x2)>>1;
round = lsb&0x1;
out_val->desc.clss = ZERO;
/* check for rounding overflow */
- hsb = 2 + out_val->desc.mantissa_size - sc_get_highest_set_bit(_mant(out_val)) - 1;
+ 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));
* 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 + result->desc.mantissa_size, temp);
+ * 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();
* 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 + result->desc.mantissa_size, temp);
+ sc_val_from_ulong(ROUNDING_BITS + result->desc.mantissa_size, temp);
_shift_left(_mant(a), temp, dividend);
build = alloca(value_size);
temp = alloca(value_size);
- sc_val_from_ulong((1 << result->desc.exponent_size)/2-1, _exp(result));
+ sc_val_from_ulong((1 << (result->desc.exponent_size - 1)) - 1, _exp(result));
if (exp > 0) {
/* temp is value of ten now */
_save_result(build);
/* temp is amount of left shift needed to put the value left of the radix point */
- sc_val_from_ulong(result->desc.mantissa_size + 2, temp);
+ sc_val_from_ulong(result->desc.mantissa_size + ROUNDING_BITS, temp);
_shift_left(build, temp, _mant(result));
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);
+ sc_val_from_ulong(mant_size + ROUNDING_BITS, exp_val);
_shift_left(_mant(result), exp_val, _mant(result));
- sc_val_from_ulong((1 << exp_size)/2-1, _exp(result));
+ sc_val_from_ulong((1 << (exp_size - 1)) - 1, _exp(result));
_normalize(result, result, 0);
UINT32 sign, exponent, mantissa0, mantissa1;
srcval.d = l;
- bias_res = ((1<<exp_size)/2-1);
+ bias_res = ((1 << (exp_size - 1)) - 1);
#ifdef HAVE_LONG_DOUBLE
mant_val = 64;
if (result == NULL) result = calc_buffer;
temp = alloca(value_size);
+ /* CLEAR the buffer, else some bits might be uninitialised */
+ memset(result, 0, fc_get_buffer_length());
+
result->desc.exponent_size = exp_size;
result->desc.mantissa_size = mant_size;
if (exponent != 0) {
/* insert the hidden bit */
sc_val_from_ulong(1, temp);
- sc_val_from_ulong(mant_val + 2, NULL);
+ sc_val_from_ulong(mant_val + ROUNDING_BITS, NULL);
_shift_left(temp, sc_get_buffer(), NULL);
}
else
/* bits from the lower word */
sc_val_from_ulong(mantissa1, temp);
- sc_val_from_ulong(2, NULL);
+ sc_val_from_ulong(ROUNDING_BITS, NULL);
_shift_left(temp, sc_get_buffer(), temp);
sc_or(_mant(result), temp, _mant(result));
* lead to wrong results */
exponent = sc_val_to_long(_exp(value)) ;
- sc_val_from_ulong(2, NULL);
+ sc_val_from_ulong(ROUNDING_BITS, NULL);
_shift_right(_mant(value), sc_get_buffer(), _mant(value));
mantissa0 = 0;
return result;
}
+ if (value->desc.clss == NAN) {
+ if (sc_get_highest_set_bit(_mant(value)) == value->desc.mantissa_size + 1)
+ return fc_get_qnan(exp_size, mant_size, result);
+ else
+ return fc_get_snan(exp_size, mant_size, result);
+ }
+
/* set the descriptor of the new value */
result->desc.exponent_size = exp_size;
result->desc.mantissa_size = mant_size;
sc_val_from_ulong((1<<exponent_size) - 2, _exp(result));
sc_max_from_bits(mantissa_size + 1, 0, _mant(result));
- sc_val_from_ulong(2, NULL);
+ sc_val_from_ulong(ROUNDING_BITS, NULL);
_shift_left(_mant(result), sc_get_buffer(), _mant(result));
return result;
return sc_sub_bits(packed_value, 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)) == 2 + value->desc.mantissa_size;
+ 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, char exp_size, char mant_size) {
+ 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 << (exp_size - 1)) - 1;
+ v = fc_get_exponent(value) + exp_bias;
+ if (0 < v && v < (1 << exp_size) - 1) {
+ /* check the mantissa */
+ v = value->desc.mantissa_size + ROUNDING_BITS - sc_get_lowest_set_bit(_mant(value));
+ return v < mant_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)
free(calc_buffer); calc_buffer = NULL;
}
+#ifdef FLTCALC_TRACE_CALC
static char buffer[100];
+#endif
/* definition of interface functions */
fp_value *fc_add(const fp_value *a, const fp_value *b, fp_value *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 "));
return result;
}
+/*
+ * 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;
+
+ if (a->sign && !mode_is_signed(dst_mode)) {
+ /* FIXME: for now we cannot convert this */
+ return 0;
+ }
+
+ assert(exp_val >= 0 && "floating point value not integral before fc_flt2int() call");
+ shift = exp_val - (a->desc.mantissa_size + ROUNDING_BITS);
+
+ if (shift > 0) {
+ sc_shlI(_mant(a), shift, 64, 0, result);
+ } else {
+ sc_shrI(_mant(a), -shift, 64, 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;
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