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float.c: fix memory overwrite with 8-, 16- or 80-bit constants

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We incorrectly clobbered 4 extra bytes when serializing 8-, 16- or
80-bit constants.  Be less smart, but actually correct.
This commit is contained in:
H. Peter Anvin 2008-01-21 16:19:52 -08:00
parent 73398c5012
commit f7bd02a07f
1 changed files with 3 additions and 20 deletions
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23
float.c
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@ -45,15 +45,6 @@ typedef uint64_t fp_2limb;
#define LIMB_ALL_BYTES ((fp_limb)0x01010101)
#define LIMB_BYTE(x) ((x)*LIMB_ALL_BYTES)
#if X86_MEMORY
#define put(a,b) (*(uint32_t *)(a) = (b))
#else
#define put(a,b) (((a)[0] = (b)), \
((a)[1] = (b) >> 8), \
((a)[2] = (b) >> 16), \
((a)[3] = (b) >> 24))
#endif
/* 112 bits + 64 bits for accuracy + 16 bits for rounding */
#define MANT_LIMBS 6
@ -650,7 +641,7 @@ enum floats {
static int to_float(const char *str, int s, uint8_t * result,
const struct ieee_format *fmt)
{
fp_limb mant[MANT_LIMBS], *mp, m;
fp_limb mant[MANT_LIMBS];
int32_t exponent = 0;
int32_t expmax = 1 << (fmt->exponent - 1);
fp_limb one_mask = LIMB_TOP_BIT >>
@ -813,16 +804,8 @@ static int to_float(const char *str, int s, uint8_t * result,
mant[0] |= minus ? LIMB_TOP_BIT : 0;
m = mant[fmt->bytes/LIMB_BYTES];
for (i = LIMB_BYTES-(fmt->bytes % LIMB_BYTES); i < LIMB_BYTES; i++)
*result++ = m >> (i*8);
for (mp = &mant[fmt->bytes/LIMB_BYTES], i = 0;
i < fmt->bytes; i += LIMB_BYTES) {
m = *--mp;
put(result, m);
result += LIMB_BYTES;
}
for (i = fmt->bytes - 1; i >= 0; i--)
*result++ = mant[i/LIMB_BYTES] >> ((i%LIMB_BYTES)*8);
return 1; /* success */
}