first commit of the new libm!

[musl] / src / math / hypotf.c

diff --git a/src/math/hypotf.c b/src/math/hypotf.c
new file mode 100644 (file)
index 0000000..40acd91
--- /dev/null
+++ b/src/math/hypotf.c
@@ -0,0 +1,88 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_hypotf.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"
+
+float hypotf(float x, float y)
+{
+       float a,b,t1,t2,y1,y2,w;
+       int32_t j,k,ha,hb;
+
+       GET_FLOAT_WORD(ha,x);
+       ha &= 0x7fffffff;
+       GET_FLOAT_WORD(hb,y);
+       hb &= 0x7fffffff;
+       if (hb > ha) {
+               a = y;
+               b = x;
+               j=ha; ha=hb; hb=j;
+       } else {
+               a = x;
+               b = y;
+       }
+       a = fabsf(a);
+       b = fabsf(b);
+       if (ha - hb > 0xf000000)  /* x/y > 2**30 */
+               return a+b;
+       k = 0;
+       if (ha > 0x58800000) {    /* a > 2**50 */
+               if(ha >= 0x7f800000) {  /* Inf or NaN */
+                       /* Use original arg order iff result is NaN; quieten sNaNs. */
+                       w = fabsf(x+0.0F) - fabsf(y+0.0F);
+                       if (ha == 0x7f800000) w = a;
+                       if (hb == 0x7f800000) w = b;
+                       return w;
+               }
+               /* scale a and b by 2**-68 */
+               ha -= 0x22000000; hb -= 0x22000000; k += 68;
+               SET_FLOAT_WORD(a, ha);
+               SET_FLOAT_WORD(b, hb);
+       }
+       if (hb < 0x26800000) {    /* b < 2**-50 */
+               if (hb <= 0x007fffff) {  /* subnormal b or 0 */
+                       if (hb == 0)
+                               return a;
+                       SET_FLOAT_WORD(t1, 0x7e800000);  /* t1 = 2^126 */
+                       b *= t1;
+                       a *= t1;
+                       k -= 126;
+               } else {   /* scale a and b by 2^68 */
+                       ha += 0x22000000;  /* a *= 2^68 */
+                       hb += 0x22000000;  /* b *= 2^68 */
+                       k -= 68;
+                       SET_FLOAT_WORD(a, ha);
+                       SET_FLOAT_WORD(b, hb);
+               }
+       }
+       /* medium size a and b */
+       w = a - b;
+       if (w > b) {
+               SET_FLOAT_WORD(t1, ha&0xfffff000);
+               t2 = a - t1;
+               w  = sqrtf(t1*t1-(b*(-b)-t2*(a+t1)));
+       } else {
+               a  = a + a;
+               SET_FLOAT_WORD(y1, hb&0xfffff000);
+               y2 = b - y1;
+               SET_FLOAT_WORD(t1,(ha+0x00800000)&0xfffff000);
+               t2 = a - t1;
+               w  = sqrtf(t1*y1-(w*(-w)-(t1*y2+t2*b)));
+       }
+       if (k != 0) {
+               SET_FLOAT_WORD(t1, 0x3f800000+(k<<23));
+               return t1*w;
+       }
+       return w;
+}