msvcrt: Fix rounding of numbers smaller than minimal subnormal.

Signed-off-by: Piotr Caban <piotr@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Piotr Caban 2020-07-23 15:38:46 +02:00 committed by Alexandre Julliard
parent 4fe481db95
commit 29288c0bc0
2 changed files with 17 additions and 13 deletions

View File

@ -413,25 +413,21 @@ int fpnum_double(struct fpnum *fp, double *d)
fp->m >>= 1;
fp->exp++;
}
/* handle subnormal that falls into regular range due to rounding */
fp->exp += (1 << (EXP_BITS-1)) - 1;
if (!fp->exp && (fp->mod == FP_ROUND_UP || (fp->mod == FP_ROUND_EVEN && fp->m & 1)))
{
if (fp->m + 1 >= (ULONGLONG)1 << MANT_BITS)
{
fp->m++;
fp->m >>= 1;
fp->exp++;
fp->mod = FP_ROUND_DOWN;
}
}
/* handle subnormals */
if (fp->exp <= 0)
{
if (fp->m & 1 && fp->mod == FP_ROUND_ZERO) fp->mod = FP_ROUND_EVEN;
else if (fp->m & 1) fp->mod = FP_ROUND_UP;
else if (fp->mod != FP_ROUND_ZERO) fp->mod = FP_ROUND_DOWN;
fp->m >>= 1;
}
while(fp->m && fp->exp<0)
{
if (fp->m & 1 && fp->mod == FP_ROUND_ZERO) fp->mod = FP_ROUND_EVEN;
else if (fp->m & 1) fp->mod = FP_ROUND_UP;
else if (fp->mod != FP_ROUND_ZERO) fp->mod = FP_ROUND_DOWN;
fp->m >>= 1;
fp->exp++;
}
@ -440,7 +436,13 @@ int fpnum_double(struct fpnum *fp, double *d)
if (fp->mod == FP_ROUND_UP || (fp->mod == FP_ROUND_EVEN && fp->m & 1))
{
fp->m++;
if (fp->m >= (ULONGLONG)1 << MANT_BITS)
/* handle subnormal that falls into regular range due to rounding */
if (fp->m == (ULONGLONG)1 << (MANT_BITS - 1))
{
fp->exp++;
}
else if (fp->m >= (ULONGLONG)1 << MANT_BITS)
{
fp->exp++;
fp->m >>= 1;

View File

@ -148,6 +148,8 @@ static void test_strtod(void)
test_strtod_str("1.7976931348623158e+308", 1.7976931348623158e+308, 23);
test_strtod_str("2.2250738585072014e-308", 2.2250738585072014e-308, 23);
test_strtod_str("4.9406564584124654e-324", 4.9406564584124654e-324, 23);
test_strtod_str("2.48e-324", 4.9406564584124654e-324, 9);
test_strtod_str_errno("2.47e-324", 0, 9, ERANGE);
}
static void test__memicmp(void)