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| author | Aurelien Jarno <aurelien@aurel32.net> | 2016-08-02 09:18:59 +0200 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2016-08-02 09:18:59 +0200 |
| commit | b74d259fe793499134eb743222cd8dd7c74a31ce (patch) | |
| tree | ec337eba9ce2431f6d9853b502d10423455c0378 /sysdeps | |
| parent | cb7f9d63b921ea1a1cbb4ab377a8484fd5da9a2b (diff) | |
| download | glibc-b74d259fe793499134eb743222cd8dd7c74a31ce.tar glibc-b74d259fe793499134eb743222cd8dd7c74a31ce.tar.gz glibc-b74d259fe793499134eb743222cd8dd7c74a31ce.tar.bz2 glibc-b74d259fe793499134eb743222cd8dd7c74a31ce.zip | |
alpha: fix trunc for big input values
The alpha specific version of trunc and truncf always add and subtract
0x1.0p23 or 0x1.0p52 even for big values. This causes this kind of
errors in the testsuite:
Failure: Test: trunc_towardzero (0x1p107)
Result:
is: 1.6225927682921334e+32 0x1.fffffffffffffp+106
should be: 1.6225927682921336e+32 0x1.0000000000000p+107
difference: 1.8014398509481984e+16 0x1.0000000000000p+54
ulp : 0.5000
max.ulp : 0.0000
Change this by returning the input value when its absolute value is
greater than 0x1.0p23 or 0x1.0p52. NaN have to go through the add and
subtract operations to get possibly silenced.
Finally remove the code to handle inexact exception, trunc should never
generate such an exception.
Changelog:
* sysdeps/alpha/fpu/s_trunc.c (__trunc): Return the input value
when its absolute value is greater than 0x1.0p52.
[_IEEE_FP_INEXACT] Remove.
* sysdeps/alpha/fpu/s_truncf.c (__truncf): Return the input value
when its absolute value is greater than 0x1.0p23.
[_IEEE_FP_INEXACT] Remove.
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/alpha/fpu/s_trunc.c | 7 | ||||
| -rw-r--r-- | sysdeps/alpha/fpu/s_truncf.c | 7 |
2 files changed, 6 insertions, 8 deletions
diff --git a/sysdeps/alpha/fpu/s_trunc.c b/sysdeps/alpha/fpu/s_trunc.c index 16cb114a72..4b986a6926 100644 --- a/sysdeps/alpha/fpu/s_trunc.c +++ b/sysdeps/alpha/fpu/s_trunc.c @@ -28,12 +28,11 @@ __trunc (double x) double two52 = copysign (0x1.0p52, x); double r, tmp; + if (isgreaterequal (fabs (x), 0x1.0p52)) + return x; + __asm ( -#ifdef _IEEE_FP_INEXACT - "addt/suic %2, %3, %1\n\tsubt/suic %1, %3, %0" -#else "addt/suc %2, %3, %1\n\tsubt/suc %1, %3, %0" -#endif : "=&f"(r), "=&f"(tmp) : "f"(x), "f"(two52)); diff --git a/sysdeps/alpha/fpu/s_truncf.c b/sysdeps/alpha/fpu/s_truncf.c index 2290f28295..3e93356166 100644 --- a/sysdeps/alpha/fpu/s_truncf.c +++ b/sysdeps/alpha/fpu/s_truncf.c @@ -27,12 +27,11 @@ __truncf (float x) float two23 = copysignf (0x1.0p23, x); float r, tmp; + if (isgreaterequal (fabsf (x), 0x1.0p23)) + return x; + __asm ( -#ifdef _IEEE_FP_INEXACT - "adds/suic %2, %3, %1\n\tsubs/suic %1, %3, %0" -#else "adds/suc %2, %3, %1\n\tsubs/suc %1, %3, %0" -#endif : "=&f"(r), "=&f"(tmp) : "f"(x), "f"(two23)); |