math: initial checkin of math functions for external apps
Bug: 29003259
Change-Id: Ie8405bce04df2493ae740b6efa3745eb02bebfcb
diff --git a/lib/libm/ef_atan2.c b/lib/libm/ef_atan2.c
new file mode 100644
index 0000000..d57480b
--- /dev/null
+++ b/lib/libm/ef_atan2.c
@@ -0,0 +1,101 @@
+/* ef_atan2.c -- float version of e_atan2.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, [email protected].
+ */
+
+/*
+ * ====================================================
+ * 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 "fdlibm.h"
+
+#ifdef __STDC__
+static const float
+#else
+static float
+#endif
+tiny = 1.0e-30,
+zero = 0.0,
+pi_o_4 = 7.8539818525e-01, /* 0x3f490fdb */
+pi_o_2 = 1.5707963705e+00, /* 0x3fc90fdb */
+pi = 3.1415927410e+00, /* 0x40490fdb */
+pi_lo = -8.7422776573e-08; /* 0xb3bbbd2e */
+
+#ifdef __STDC__
+ float __ieee754_atan2f(float y, float x)
+#else
+ float __ieee754_atan2f(y,x)
+ float y,x;
+#endif
+{
+ float z;
+ __int32_t k,m,hx,hy,ix,iy;
+
+ GET_FLOAT_WORD(hx,x);
+ ix = hx&0x7fffffff;
+ GET_FLOAT_WORD(hy,y);
+ iy = hy&0x7fffffff;
+ if(FLT_UWORD_IS_NAN(ix)||
+ FLT_UWORD_IS_NAN(iy)) /* x or y is NaN */
+ return x+y;
+ if(hx==0x3f800000) return atanf(y); /* x=1.0 */
+ m = ((hy>>31)&1)|((hx>>30)&2); /* 2*sign(x)+sign(y) */
+
+ /* when y = 0 */
+ if(FLT_UWORD_IS_ZERO(iy)) {
+ switch(m) {
+ case 0:
+ case 1: return y; /* atan(+-0,+anything)=+-0 */
+ case 2: return pi+tiny;/* atan(+0,-anything) = pi */
+ case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */
+ }
+ }
+ /* when x = 0 */
+ if(FLT_UWORD_IS_ZERO(ix)) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
+
+ /* when x is INF */
+ if(FLT_UWORD_IS_INFINITE(ix)) {
+ if(FLT_UWORD_IS_INFINITE(iy)) {
+ switch(m) {
+ case 0: return pi_o_4+tiny;/* atan(+INF,+INF) */
+ case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */
+ case 2: return (float)3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/
+ case 3: return (float)-3.0*pi_o_4-tiny;/*atan(-INF,-INF)*/
+ }
+ } else {
+ switch(m) {
+ case 0: return zero ; /* atan(+...,+INF) */
+ case 1: return -zero ; /* atan(-...,+INF) */
+ case 2: return pi+tiny ; /* atan(+...,-INF) */
+ case 3: return -pi-tiny ; /* atan(-...,-INF) */
+ }
+ }
+ }
+ /* when y is INF */
+ if(FLT_UWORD_IS_INFINITE(iy)) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
+
+ /* compute y/x */
+ k = (iy-ix)>>23;
+ if(k > 60) z=pi_o_2+(float)0.5*pi_lo; /* |y/x| > 2**60 */
+ else if(hx<0&&k<-60) z=0.0; /* |y|/x < -2**60 */
+ else z=atanf(fabsf(y/x)); /* safe to do y/x */
+ switch (m) {
+ case 0: return z ; /* atan(+,+) */
+ case 1: {
+ __uint32_t zh;
+ GET_FLOAT_WORD(zh,z);
+ SET_FLOAT_WORD(z,zh ^ 0x80000000);
+ }
+ return z ; /* atan(-,+) */
+ case 2: return pi-(z-pi_lo);/* atan(+,-) */
+ default: /* case 3 */
+ return (z-pi_lo)-pi;/* atan(-,-) */
+ }
+}
