math: sin cos cleanup

[musl] / src / math / sincosf.c

diff --git a/src/math/sincosf.c b/src/math/sincosf.c
index 5e3b9a4..1b50f01 100644 (file)
--- 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;
        }