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authorSzabolcs Nagy <nsz@port70.net>2013-05-18 14:40:22 +0000
committerSzabolcs Nagy <nsz@port70.net>2013-05-18 14:40:22 +0000
commitbfda37935867f9bf271d6074db0accf05c63ad10 (patch)
tree92d7fffcc6fb7fd9caad6f3bde14dcd768d32b66 /src/math/cos.c
parent1d5ba3bb5a3f55e10db05219638cfcd967d65417 (diff)
downloadmusl-bfda37935867f9bf271d6074db0accf05c63ad10.tar.gz
math: sin cos cleanup
* use unsigned arithmetics * use unsigned to store arg reduction quotient (so n&3 is understood) * remove z=0.0 variables, use literal 0 * raise underflow and inexact exceptions properly when x is small * fix spurious underflow in tanl
Diffstat (limited to 'src/math/cos.c')
-rw-r--r--src/math/cos.c20
1 files changed, 11 insertions, 9 deletions
diff --git a/src/math/cos.c b/src/math/cos.c
index 76990e7f..ee97f68b 100644
--- a/src/math/cos.c
+++ b/src/math/cos.c
@@ -44,26 +44,28 @@
double cos(double x)
{
- double y[2],z=0.0;
- int32_t n, ix;
+ double y[2];
+ uint32_t ix;
+ unsigned n;
GET_HIGH_WORD(ix, x);
+ ix &= 0x7fffffff;
/* |x| ~< pi/4 */
- ix &= 0x7fffffff;
if (ix <= 0x3fe921fb) {
- if (ix < 0x3e46a09e) /* if x < 2**-27 * sqrt(2) */
- /* raise inexact if x != 0 */
- if ((int)x == 0)
- return 1.0;
- return __cos(x, z);
+ if (ix < 0x3e46a09e) { /* |x| < 2**-27 * sqrt(2) */
+ /* raise inexact if x!=0 */
+ FORCE_EVAL(x + 0x1p120f);
+ return 1.0;
+ }
+ return __cos(x, 0);
}
/* cos(Inf or NaN) is NaN */
if (ix >= 0x7ff00000)
return x-x;
- /* argument reduction needed */
+ /* argument reduction */
n = __rem_pio2(x, y);
switch (n&3) {
case 0: return __cos(y[0], y[1]);