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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/sincosf.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/sincosf.c')
-rw-r--r--src/math/sincosf.c45
1 files changed, 24 insertions, 21 deletions
diff --git a/src/math/sincosf.c b/src/math/sincosf.c
index 5e3b9a41..1b50f01c 100644
--- a/src/math/sincosf.c
+++ b/src/math/sincosf.c
@@ -25,21 +25,23 @@ s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
void sincosf(float x, float *sin, float *cos)
{
- double y, s, c;
- uint32_t n, hx, ix;
+ double y;
+ float_t s, c;
+ uint32_t ix;
+ unsigned n, sign;
- GET_FLOAT_WORD(hx, x);
- ix = hx & 0x7fffffff;
+ GET_FLOAT_WORD(ix, x);
+ sign = ix >> 31;
+ ix &= 0x7fffffff;
/* |x| ~<= pi/4 */
if (ix <= 0x3f490fda) {
/* |x| < 2**-12 */
if (ix < 0x39800000) {
- /* raise inexact if x != 0 */
- if((int)x == 0) {
- *sin = x;
- *cos = 1.0f;
- }
+ /* raise inexact if x!=0 and underflow if subnormal */
+ FORCE_EVAL(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f);
+ *sin = x;
+ *cos = 1.0f;
return;
}
*sin = __sindf(x);
@@ -50,34 +52,35 @@ void sincosf(float x, float *sin, float *cos)
/* |x| ~<= 5*pi/4 */
if (ix <= 0x407b53d1) {
if (ix <= 0x4016cbe3) { /* |x| ~<= 3pi/4 */
- if (hx < 0x80000000) {
- *sin = __cosdf(x - s1pio2);
- *cos = __sindf(s1pio2 - x);
- } else {
+ if (sign) {
*sin = -__cosdf(x + s1pio2);
*cos = __sindf(x + s1pio2);
+ } else {
+ *sin = __cosdf(s1pio2 - x);
+ *cos = __sindf(s1pio2 - x);
}
return;
}
- *sin = __sindf(hx < 0x80000000 ? s2pio2 - x : -s2pio2 - x);
- *cos = -__cosdf(hx < 0x80000000 ? x - s2pio2 : x + s2pio2);
+ /* -sin(x+c) is not correct if x+c could be 0: -0 vs +0 */
+ *sin = -__sindf(sign ? x + s2pio2 : x - s2pio2);
+ *cos = -__cosdf(sign ? x + s2pio2 : x - s2pio2);
return;
}
/* |x| ~<= 9*pi/4 */
if (ix <= 0x40e231d5) {
if (ix <= 0x40afeddf) { /* |x| ~<= 7*pi/4 */
- if (hx < 0x80000000) {
+ if (sign) {
+ *sin = __cosdf(x + s3pio2);
+ *cos = -__sindf(x + s3pio2);
+ } else {
*sin = -__cosdf(x - s3pio2);
*cos = __sindf(x - s3pio2);
- } else {
- *sin = __cosdf(x + s3pio2);
- *cos = __sindf(-s3pio2 - x);
}
return;
}
- *sin = __sindf(hx < 0x80000000 ? x - s4pio2 : x + s4pio2);
- *cos = __cosdf(hx < 0x80000000 ? x - s4pio2 : x + s4pio2);
+ *sin = __sindf(sign ? x + s4pio2 : x - s4pio2);
+ *cos = __cosdf(sign ? x + s4pio2 : x - s4pio2);
return;
}