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float: support packed-BCD constants in 'dt' statements

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Support packed-BCD constants in 'dt' statements (and elsewhere 80-bit
floating point is handled), using MASM syntax (terminal 'p').
This commit is contained in:
H. Peter Anvin 2008-07-03 20:12:37 -07:00
parent 5aa689f80d
commit 45f22924ea
1 changed files with 70 additions and 7 deletions
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77
float.c
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@ -492,7 +492,7 @@ static bool ieee_flconvert_bin(const char *string, int bits,
int32_t twopwr;
bool seendot, seendigit;
unsigned char c;
int radix = 1 << bits;
const int radix = 1 << bits;
fp_limb v;
twopwr = 0;
@ -638,21 +638,84 @@ enum floats {
FL_SNAN
};
static int to_float(const char *str, int s, uint8_t * result,
static int to_packed_bcd(const char *str, const char *strend,
int s, uint8_t *result,
const struct ieee_format *fmt)
{
int n = 0;
char c;
int tv = -1;
const char *p = strend-2;
if (fmt != &ieee_80) {
error(ERR_NONFATAL|ERR_PASS1,
"packed BCD requires an 80-bit format");
return 0;
}
while (p >= str) {
c = *p--;
if (c >= '0' && c <= '9') {
if (tv < 0) {
if (n == 9) {
error(ERR_WARNING|ERR_PASS1,
"packed BCD truncated to 18 digits");
}
tv = c-'0';
} else {
if (n < 9)
*result++ = tv + ((c-'0') << 4);
n++;
tv = -1;
}
} else if (c == '_') {
/* do nothing */
} else {
error(ERR_NONFATAL|ERR_PASS1,
"invalid character `%c' in packed BCD constant", c);
return 0;
}
}
if (tv >= 0) {
if (n < 9)
*result++ = tv;
n++;
}
while (n < 9) {
*result++ = 0;
n++;
}
*result = (s < 0) ? 0x80 : 0;
return 1; /* success */
}
static int to_float(const char *str, int s, uint8_t *result,
const struct ieee_format *fmt)
{
fp_limb mant[MANT_LIMBS];
int32_t exponent = 0;
int32_t expmax = 1 << (fmt->exponent - 1);
const int32_t expmax = 1 << (fmt->exponent - 1);
fp_limb one_mask = LIMB_TOP_BIT >>
((fmt->exponent+fmt->explicit) % LIMB_BITS);
int one_pos = (fmt->exponent+fmt->explicit)/LIMB_BITS;
const int one_pos = (fmt->exponent+fmt->explicit)/LIMB_BITS;
int i;
int shift;
enum floats type;
bool ok;
bool minus = s < 0;
int bits = fmt->bytes * 8;
const bool minus = s < 0;
const int bits = fmt->bytes * 8;
const char *strend;
if (!str[0]) {
error(ERR_PANIC,
"internal errror: empty string passed to float_const");
return 0;
}
strend = strchr(str, '\0');
if (strend[-1] == 'P' || strend[-1] == 'p')
return to_packed_bcd(str, strend, s, result, fmt);
if (str[0] == '_') {
/* Special tokens */
@ -810,7 +873,7 @@ static int to_float(const char *str, int s, uint8_t * result,
return 1; /* success */
}
int float_const(const char *number, int sign, uint8_t * result,
int float_const(const char *number, int sign, uint8_t *result,
int bytes, efunc err)
{
error = err;