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| author |   Siddhesh Poyarekar <siddhesh@sourceware.org> | 2016-10-06 00:34:26 +0530 |
|---|---|---|
| committer | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2016-10-06 00:34:26 +0530 |
| commit | ba4e688461a0e3171a6c515040ec9200319070b6 (patch) | |
| tree | 361d512b9b3abb301b3ffa313c73631bd6b69d2c /sysdeps/ieee754/dbl-64/s_sin.c | |
| parent | Make the quadrant shift K a bool in do_sincos_* functions (diff) | |
| download | glibc-ba4e688461a0e3171a6c515040ec9200319070b6.tar.gz glibc-ba4e688461a0e3171a6c515040ec9200319070b6.tar.bz2 glibc-ba4e688461a0e3171a6c515040ec9200319070b6.zip | |
Check n instead of k1 to decide on sign of sin/cos result
For k1 in 1 and 3, n can only have values of 0 and 2, so checking k1 &
2 is equivalent to checking n & 2. We prefer the latter so that we
don't use k1 for anything other than selecting the quadrant in
do_sincos_1, thus dropping it completely.
The previous logic was:
"Compute sine for the value and based on the new rotated quadrant
(k1) negate the value if we're in the fourth quadrant."
With this change, the logic now is:
"Compute sine for the value and negate it if we were either (1) in
the fourth quadrant or (2) we actually wanted the cosine and were
in the third quadrant."
* sysdeps/ieee754/dbl-64/s_sin.c (do_sincos_1): Check N
instead of K1.
Diffstat (limited to 'sysdeps/ieee754/dbl-64/s_sin.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/s_sin.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_sin.c b/sysdeps/ieee754/dbl-64/s_sin.c index 76cf99619a..67bdebfd6c 100644 --- a/sysdeps/ieee754/dbl-64/s_sin.c +++ b/sysdeps/ieee754/dbl-64/s_sin.c @@ -353,7 +353,7 @@ do_sincos_1 (double a, double da, double x, int4 n, bool shift_quadrant) case 3: res = do_cos (a, da, &cor); cor = 1.025 * cor + __copysign (eps, cor); - retval = ((res == res + cor) ? ((k1 & 2) ? -res : res) + retval = ((res == res + cor) ? ((n & 2) ? -res : res) : sloww2 (a, da, x, n)); break; } |