Index: fusl/src/math/atan2f.c |
diff --git a/fusl/src/math/atan2f.c b/fusl/src/math/atan2f.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..c634d00fc93195f63d25b59c0ae6e4a0e8e826d2 |
--- /dev/null |
+++ b/fusl/src/math/atan2f.c |
@@ -0,0 +1,83 @@ |
+/* origin: FreeBSD /usr/src/lib/msun/src/e_atan2f.c */ |
+/* |
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
+ */ |
+/* |
+ * ==================================================== |
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
+ * |
+ * Developed at SunPro, a Sun Microsystems, Inc. business. |
+ * Permission to use, copy, modify, and distribute this |
+ * software is freely granted, provided that this notice |
+ * is preserved. |
+ * ==================================================== |
+ */ |
+ |
+#include "libm.h" |
+ |
+static const float |
+pi = 3.1415927410e+00, /* 0x40490fdb */ |
+pi_lo = -8.7422776573e-08; /* 0xb3bbbd2e */ |
+ |
+float atan2f(float y, float x) |
+{ |
+ float z; |
+ uint32_t m,ix,iy; |
+ |
+ if (isnan(x) || isnan(y)) |
+ return x+y; |
+ GET_FLOAT_WORD(ix, x); |
+ GET_FLOAT_WORD(iy, y); |
+ if (ix == 0x3f800000) /* x=1.0 */ |
+ return atanf(y); |
+ m = ((iy>>31)&1) | ((ix>>30)&2); /* 2*sign(x)+sign(y) */ |
+ ix &= 0x7fffffff; |
+ iy &= 0x7fffffff; |
+ |
+ /* when y = 0 */ |
+ if (iy == 0) { |
+ switch (m) { |
+ case 0: |
+ case 1: return y; /* atan(+-0,+anything)=+-0 */ |
+ case 2: return pi; /* atan(+0,-anything) = pi */ |
+ case 3: return -pi; /* atan(-0,-anything) =-pi */ |
+ } |
+ } |
+ /* when x = 0 */ |
+ if (ix == 0) |
+ return m&1 ? -pi/2 : pi/2; |
+ /* when x is INF */ |
+ if (ix == 0x7f800000) { |
+ if (iy == 0x7f800000) { |
+ switch (m) { |
+ case 0: return pi/4; /* atan(+INF,+INF) */ |
+ case 1: return -pi/4; /* atan(-INF,+INF) */ |
+ case 2: return 3*pi/4; /*atan(+INF,-INF)*/ |
+ case 3: return -3*pi/4; /*atan(-INF,-INF)*/ |
+ } |
+ } else { |
+ switch (m) { |
+ case 0: return 0.0f; /* atan(+...,+INF) */ |
+ case 1: return -0.0f; /* atan(-...,+INF) */ |
+ case 2: return pi; /* atan(+...,-INF) */ |
+ case 3: return -pi; /* atan(-...,-INF) */ |
+ } |
+ } |
+ } |
+ /* |y/x| > 0x1p26 */ |
+ if (ix+(26<<23) < iy || iy == 0x7f800000) |
+ return m&1 ? -pi/2 : pi/2; |
+ |
+ /* z = atan(|y/x|) with correct underflow */ |
+ if ((m&2) && iy+(26<<23) < ix) /*|y/x| < 0x1p-26, x < 0 */ |
+ z = 0.0; |
+ else |
+ z = atanf(fabsf(y/x)); |
+ switch (m) { |
+ case 0: return z; /* atan(+,+) */ |
+ case 1: return -z; /* atan(-,+) */ |
+ case 2: return pi - (z-pi_lo); /* atan(+,-) */ |
+ default: /* case 3 */ |
+ return (z-pi_lo) - pi; /* atan(-,-) */ |
+ } |
+} |