efficient sincos based on sin and cos

[musl] / src / math / sincosl.c

diff --git a/src/math/sincosl.c b/src/math/sincosl.c
new file mode 100644 (file)
index 0000000..378dc97
--- /dev/null
+++ b/src/math/sincosl.c
@@ -0,0 +1,66 @@
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+void sincosl(long double x, long double *sin, long double *cos)
+{
+       double s, c;
+       sincos(x, &s, &c);
+       *sin = s;
+       *cos = c;
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+#include "__rem_pio2l.h"
+
+void sincosl(long double x, long double *sin, long double *cos)
+{
+       union IEEEl2bits u;
+       int n;
+       long double y[2], s, c;
+
+       u.e = x;
+       u.bits.sign = 0;
+
+       /* x = +-0 or subnormal */
+       if (!u.bits.exp) {
+               *sin = x;
+               *cos = 1.0;
+               return;
+       }
+
+       /* x = nan or inf */
+       if (u.bits.exp == 0x7fff) {
+               *sin = *cos = x - x;
+               return;
+       }
+
+       /* |x| < pi/4 */
+       if (u.e < M_PI_4) {
+               *sin = __sinl(x, 0, 0);
+               *cos = __cosl(x, 0);
+               return;
+       }
+
+       n = __rem_pio2l(x, y);
+       s = __sinl(y[0], y[1], 1);
+       c = __cosl(y[0], y[1]);
+       switch (n & 3) {
+       case 0:
+               *sin = s;
+               *cos = c;
+               break;
+       case 1:
+               *sin = c;
+               *cos = -s;
+               break;
+       case 2:
+               *sin = -s;
+               *cos = -c;
+               break;
+       case 3:
+       default:
+               *sin = -c;
+               *cos = s;
+               break;
+       }
+}
+#endif