* NOTES
******/
-#include <assert.h> /* assertions */
-#include <string.h> /* memset/memcmp */
-
#include "strcalc.h"
-#include <stdio.h> /* output for error messages */
#include <stdlib.h>
+#include <assert.h> /* assertions */
+#include <string.h> /* memset/memcmp */
+#include <stdio.h> /* output for error messages */
+#include <limits.h> /* definition of LONG_MIN, used in sc_get_val_from_long */
/*
* local definitions and macros
#define fail_char(a, b, c, d) _fail_char((a), (b), (c), (d), __FILE__, __LINE__)
+#ifdef STRCALC_DEBUG_COMPUTATION
+# define DEBUGPRINTF_COMPUTATION(x) printf x
+#else
+# define DEBUGPRINTF_COMPUTATION(x) ((void)0)
+#endif
#ifdef STRCALC_DEBUG
- /* shortcut output for debugging only, gices always full precisition */
-# define sc_print_hex(a) sc_print((a), 0, SC_HEX)
-# define sc_print_dec(a) sc_print((a), 0, SC_DEC)
-# define sc_print_oct(a) sc_print((a), 0, SC_OCT)
-# define sc_print_bin(a) sc_print((a), 0, SC_BIN)
# define DEBUGPRINTF(x) printf x
#else
# define DEBUGPRINTF(x) ((void)0)
#endif
+
/*
* private variables
*/
static char *calc_buffer = NULL; /* buffer holding all results */
static char *output_buffer = NULL; /* buffer for output */
-static int BIT_PATTERN_SIZE;
-static int CALC_BUFFER_SIZE;
-static int MAX_VALUE_SIZE;
+static int BIT_PATTERN_SIZE; /* maximum number of bits */
+static int CALC_BUFFER_SIZE; /* size of internally stored values */
+static int MAX_VALUE_SIZE; /* maximum size of values */
+
+static int carry_flag; /* some computation set carry_flag: */
+ /* rightshift if bits were lost due to shifting */
+ /* division if there was a remainder */
static const char max_digit[4] = { SC_0, SC_1, SC_3, SC_7 };
static const char min_digit[4] = { SC_F, SC_E, SC_C, SC_8 };
SC_8, SC_8, SC_8, SC_8, SC_C, SC_C, SC_C, SC_C },
{ SC_0, SC_1, SC_0, SC_1, SC_4, SC_5, SC_4, SC_5,
- SC_8, SC_9, SC_8, SC_9, SC_D, SC_E, SC_D, SC_E },
+ SC_8, SC_9, SC_8, SC_9, SC_C, SC_D, SC_C, SC_D },
{ SC_0, SC_0, SC_2, SC_2, SC_4, SC_4, SC_6, SC_6,
SC_8, SC_8, SC_A, SC_A, SC_C, SC_C, SC_E, SC_E },
return (val[CALC_BUFFER_SIZE-1] <= SC_7) ? (1) : (-1);
}
+/*
+ * returns non-zero if bit at position pos is set
+ */
+static int _bit(const char *val, int pos)
+{
+ int bit = pos & 3;
+ int nibble = pos >> 2;
+
+ return _bitisset(val[nibble], bit);
+}
+
static void _inc(char *val, char *buffer)
{
int counter = 0;
return;
}
}
- /* here a carry could be lost, this is intended because this will only
- * happen when a value changes sign. */
+ /* here a carry could be lost, this is intended because this should
+ * happen only when a value changes sign. */
}
static void _negate(const char *val, char *buffer)
buffer[counter] = add2[0];
carry = add_table[_val(add1[1])][_val(add2[1])][0];
}
- /* loose last carry, which will occur only when changing sign */
}
static void _mul(const char *val1, const char *val2, char *buffer)
/* A carry may hang over */
/* c_outer is always smaller than MAX_VALUE_SIZE! */
temp_buffer[MAX_VALUE_SIZE + c_outer] = carry;
+ carry = SC_0;
}
}
memset(quot, SC_0, CALC_BUFFER_SIZE);
memset(rem, SC_0, CALC_BUFFER_SIZE);
+ /* if the divisor is zero this won't work (quot is zero) */
+ if (sc_comp(divisor, quot) == 0) assert(0 && "division by zero!");
+
/* if the dividend is zero result is zero (quot is zero)*/
if (sc_comp(dividend, quot) == 0)
return;
- /* if the divisor is zero this won't work (quot is zero) */
- if (sc_comp(divisor, quot) == 0) assert(0 && "division by zero!");
if (_sign(dividend) == -1)
{
minus_divisor = neg_val2;
}
- /* if divisor >= dividend quotision is easy
+ /* if divisor >= dividend division is easy
* (remember these are absolute values) */
switch (sc_comp(dividend, divisor))
{
memcpy(rem, dividend, CALC_BUFFER_SIZE);
return;
- default: /* unluckily quotision is necessary :( */
+ default: /* unluckily division is necessary :( */
break;
}
- for (c_dividend = MAX_VALUE_SIZE - 1; c_dividend >= 0; c_dividend--)
+ for (c_dividend = CALC_BUFFER_SIZE - 1; c_dividend >= 0; c_dividend--)
{
_push(dividend[c_dividend], rem);
_push(SC_0, quot);
}
}
+ carry_flag = !sc_is_zero(rem);
+
if (sign)
{
_negate(quot, quot);
shift = offset % 4;
offset = offset / 4;
+ /* check if any bits are lost, and set carry_flag is so */
+ for (counter = 0; counter < offset; counter++)
+ {
+ if (val1[counter] != carry_flag)
+ {
+ carry_flag = 1;
+ break;
+ }
+ }
+ if ((carry_flag == 0) && (_val(val1[counter]) & shift) != 0)
+ carry_flag = 1;
+
+ /* shift digits to the right with offset, carry and all */
counter = 0;
if (radius/4 - offset > 0) {
buffer[counter] = shrs_table[_val(val1[offset])][shift][0];
counter = 1;
}
-
- /* shift digits to the right with offset, carry and all */
for (; counter < radius/4 - offset; counter++)
{
-
shrs = shrs_table[_val(val1[counter + offset])][shift];
buffer[counter] = shrs[0];
buffer[counter-1] = or_table[_val(buffer[counter-1])][_val(shrs[1])];
/* the last digit is special in regard of signed/unsigned shift */
bitoffset = radius%4;
- msd = val1[radius/4]; /* most significant digit */
+ msd = (radius/4<CALC_BUFFER_SIZE)?(val1[radius/4]):(sign); /* most significant digit */
/* remove sign bits if mode was signed and this is an unsigned shift */
if (!signed_shift && is_signed) {
} else {
buffer[counter] = shrs[0];
}
+
if (counter > 0) buffer[counter - 1] = or_table[_val(buffer[counter-1])][_val(shrs[1])];
/* fill with SC_F or SC_0 depending on sign */
char temp1[CALC_BUFFER_SIZE];
char temp2[CALC_BUFFER_SIZE];
- const char *shl;
- char carry = SC_0;
-
- int counter, old_counter;
- int shift;
- int bitoffset;
-
offset = offset % radius;
/* rotation by multiples of the typelength is identity */
_shl(val1, temp1, offset, radius, is_signed);
_shr(val1, temp2, radius - offset, radius, is_signed, 0);
_bitor(temp1, temp2, buffer);
+ carry_flag = 0; /* set by shr, but due to rot this is false */
}
/*****************************************************************************
base[1] = SC_0; base[0] = SC_A;
}
- /* begin string evaluation, from left to right */
+ /* BEGIN string evaluation, from left to right */
while (len > 0)
{
switch (*str)
void sc_val_from_long(long value)
{
char *pos;
- int sign;
+ char sign, is_minlong;
pos = calc_buffer;
sign = (value < 0);
+ is_minlong = value == LONG_MIN;
- /* FIXME MININT won't work */
- if (sign) value = -value;
+ /* use absolute value, special treatment of MIN_LONG */
+ if (sign) {
+ if (is_minlong)
+ value = -(value+1);
+ else
+ value = -value;
+ }
CLEAR_CALC_BUFFER();
value /= 16;
}
- if (sign) _negate(calc_buffer, calc_buffer);
+
+ if (sign) {
+ if (is_minlong) _inc(calc_buffer, calc_buffer);
+ _negate(calc_buffer, calc_buffer);
+ }
}
long sc_val_to_long(const void *val)
const char *val1 = (const char *)value1;
const char *val2 = (const char *)value2;
CLEAR_CALC_BUFFER();
+ carry_flag = 0;
- DEBUGPRINTF(("%s ", sc_print(value1, SC_HEX)));
+ DEBUGPRINTF_COMPUTATION(("%s ", sc_print_hex(value1)));
switch (op)
{
case SC_NEG:
_negate(val1, calc_buffer);
- DEBUGPRINTF(("negated: %s\n", sc_print_hex(calc_buffer)));
+ DEBUGPRINTF_COMPUTATION(("negated: %s\n", sc_print_hex(calc_buffer)));
return;
case SC_OR:
- DEBUGPRINTF(("| "));
+ DEBUGPRINTF_COMPUTATION(("| "));
_bitor(val1, val2, calc_buffer);
break;
case SC_AND:
- DEBUGPRINTF(("& "));
+ DEBUGPRINTF_COMPUTATION(("& "));
_bitand(val1, val2, calc_buffer);
break;
case SC_XOR:
- DEBUGPRINTF(("^ "));
+ DEBUGPRINTF_COMPUTATION(("^ "));
_bitxor(val1, val2, calc_buffer);
break;
case SC_NOT:
_bitnot(val1, calc_buffer);
- DEBUGPRINTF(("bit-negated: %s\n", sc_print_hex(calc_buffer)));
+ DEBUGPRINTF_COMPUTATION(("bit-negated: %s\n", sc_print_hex(calc_buffer)));
return;
case SC_ADD:
- DEBUGPRINTF(("+ "));
+ DEBUGPRINTF_COMPUTATION(("+ "));
_add(val1, val2, calc_buffer);
break;
case SC_SUB:
- DEBUGPRINTF(("- "));
+ DEBUGPRINTF_COMPUTATION(("- "));
_sub(val1, val2, calc_buffer);
break;
case SC_MUL:
- DEBUGPRINTF(("* "));
+ DEBUGPRINTF_COMPUTATION(("* "));
_mul(val1, val2, calc_buffer);
break;
case SC_DIV:
- DEBUGPRINTF(("/ "));
+ DEBUGPRINTF_COMPUTATION(("/ "));
_divmod(val1, val2, calc_buffer, unused_res);
break;
case SC_MOD:
- DEBUGPRINTF(("%% "));
+ DEBUGPRINTF_COMPUTATION(("%% "));
_divmod(val1, val2, unused_res, calc_buffer);
break;
default:
assert(0);
}
- DEBUGPRINTF(("%s -> ", sc_print_hex(value2)));
- DEBUGPRINTF(("%s\n", sc_print_hex(calc_buffer)));
+ DEBUGPRINTF_COMPUTATION(("%s -> ", sc_print_hex(value2)));
+ DEBUGPRINTF_COMPUTATION(("%s\n", sc_print_hex(calc_buffer)));
}
void sc_bitcalc(const void* value1, const void* value2, int radius, int sign, unsigned op)
const char *val2 = (const char *)value2;
long offset;
+ carry_flag = 0;
offset = sc_val_to_long(val2);
- DEBUGPRINTF(("%s ", sc_print_hex(value1)));
+ DEBUGPRINTF_COMPUTATION(("%s ", sc_print_hex(value1)));
switch (op)
{
case SC_SHL:
- DEBUGPRINTF(("<< %d ", offset));
+ DEBUGPRINTF_COMPUTATION(("<< %d ", offset));
_shl(val1, calc_buffer, offset, radius, sign);
break;
case SC_SHR:
- DEBUGPRINTF((">> %d ", offset));
+ DEBUGPRINTF_COMPUTATION((">> %d ", offset));
_shr(val1, calc_buffer, offset, radius, sign, 0);
break;
case SC_SHRS:
- DEBUGPRINTF((">>> %d ", offset));
+ DEBUGPRINTF_COMPUTATION((">>> %d ", offset));
_shr(val1, calc_buffer, offset, radius, sign, 1);
break;
case SC_ROT:
- DEBUGPRINTF(("<<>> %d ", offset));
+ DEBUGPRINTF_COMPUTATION(("<<>> %d ", offset));
_rot(val1, calc_buffer, offset, radius, sign);
break;
default:
assert(0);
}
- DEBUGPRINTF(("-> %s\n", sc_print_hex(calc_buffer)));
+ DEBUGPRINTF_COMPUTATION(("-> %s\n", sc_print_hex(calc_buffer)));
}
int sc_comp(const void* value1, const void* value2)
{
const char *val = (const char*)value;
int high, counter;
- char sign;
high = CALC_BUFFER_SIZE * 4;
return low;
}
+int sc_is_zero(const void *value)
+{
+ const char* val = (const char *)value;
+ int counter;
+
+ for (counter = 0; counter < CALC_BUFFER_SIZE; counter++) {
+ if (val[counter] != SC_0) return 0;
+ }
+ return 1;
+}
+
+int sc_is_negative(const void *value)
+{
+ return _sign(value) == -1;
+}
+
+int sc_had_carry(void)
+{
+ return carry_flag;
+}
+
unsigned char sc_sub_bits(const void *value, int len, unsigned byte_ofs)
{
const char *val = (const char *)value;
/*
* convert to a string
+ * XXX Doesn't check buffer bounds
*/
const char *sc_print(const void *value, unsigned bits, enum base_t base)
{
+ static const char big_digits[] = "0123456789ABCDEF";
+ static const char small_digits[] = "0123456789abcdef";
+
char base_val[CALC_BUFFER_SIZE];
char div1_res[CALC_BUFFER_SIZE];
char div2_res[CALC_BUFFER_SIZE];
const char *p;
char *m, *n, *t;
char *pos;
+ const char *digits = small_digits;
- pos = output_buffer + BIT_PATTERN_SIZE;
- *pos = '\0';
+ pos = output_buffer + BIT_PATTERN_SIZE ;
+ *(--pos) = '\0';
/* special case */
- if (bits == 0)
+ if (bits == 0) {
bits = BIT_PATTERN_SIZE;
-
+#ifdef STRCALC_DEBUG_FULLPRINT
+ bits <<= 1;
+#endif
+ }
nibbles = bits >> 2;
switch (base) {
case SC_HEX:
- for (counter = 0; counter < nibbles; ++counter)
- *(--pos) = "0123456789abcdef"[_val(val[counter])];
+ digits = big_digits;
+ case SC_hex:
+ for (counter = 0; counter < nibbles; ++counter) {
+ *(--pos) = digits[_val(val[counter])];
+#ifdef STRCALC_DEBUG_GROUPPRINT
+ if ((counter+1)%8 == 0)
+ *(--pos) = ' ';
+#endif
+ }
/* last nibble must be masked */
if (bits & 3) {
x = and_table[_val(val[++counter])][bits & 3];
- *(--pos) = "0123456789abcdef"[_val(x)];
+ *(--pos) = digits[_val(x)];
}
/* now kill zeros */
- for (; counter > 1; --counter, ++pos)
+ for (; counter > 1; --counter, ++pos) {
+#ifdef STRCALC_DEBUG_GROUPPRINT
+ if (pos[0] == ' ') ++pos;
+#endif
if (pos[0] != '0')
break;
+ }
break;
case SC_BIN:
memset(base_val, SC_0, CALC_BUFFER_SIZE);
base_val[0] = base == SC_DEC ? SC_A : SC_8;
- m = val;
+ p = val;
sign = 0;
if (base == SC_DEC) {
/* check for negative values */
- if (_sign(val) == -1) {
+ if (_bit(val, bits - 1)) {
_negate(val, div2_res);
sign = 1;
- m = div2_res;
+ p = div2_res;
}
}
/* transfer data into oscilating buffers */
memset(div1_res, SC_0, CALC_BUFFER_SIZE);
for (counter = 0; counter < nibbles; ++counter)
- div1_res[counter] = m[counter];
+ div1_res[counter] = p[counter];
/* last nibble must be masked */
if (bits & 3) {
++counter;
- div1_res[counter] = and_table[_val(m[counter])][bits & 3];
+ div1_res[counter] = and_table[_val(p[counter])][bits & 3];
}
m = div1_res;
t = m;
m = n;
n = t;
- *(--pos) = "0123456789abcdef"[_val(rem_res[0])];
+ *(--pos) = digits[_val(rem_res[0])];
x = 0;
for (i = 0; i < sizeof(div1_res); ++i)
CALC_BUFFER_SIZE = (4 * precision_in_bytes);
MAX_VALUE_SIZE = (2 * precision_in_bytes);
- calc_buffer = malloc(CALC_BUFFER_SIZE * sizeof(char));
- output_buffer = malloc(BIT_PATTERN_SIZE * sizeof(char));
+ calc_buffer = malloc(CALC_BUFFER_SIZE+1 * sizeof(char));
+ output_buffer = malloc(BIT_PATTERN_SIZE+1 * sizeof(char));
if (calc_buffer == NULL || output_buffer == NULL)
{
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