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author | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2016-10-06 00:34:26 +0530 |
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committer | Siddhesh Poyarekar <siddhesh@sourceware.org> | 2016-10-06 00:34:26 +0530 |
commit | ba4e688461a0e3171a6c515040ec9200319070b6 (patch) | |
tree | 361d512b9b3abb301b3ffa313c73631bd6b69d2c /manual | |
parent | b8b7e5e644363f9ab6ea6df5d4a44389d28e5450 (diff) | |
download | glibc-ba4e688461a0e3171a6c515040ec9200319070b6.zip glibc-ba4e688461a0e3171a6c515040ec9200319070b6.tar.gz glibc-ba4e688461a0e3171a6c515040ec9200319070b6.tar.bz2 |
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 'manual')
0 files changed, 0 insertions, 0 deletions