math: finished cosh.c cleanup

[musl] / src / math / coshf.c

diff --git a/src/math/coshf.c b/src/math/coshf.c
index 2bed125..b09f2ee 100644 (file)
--- a/src/math/coshf.c
+++ b/src/math/coshf.c
@@ -1,54 +1,33 @@
-/* origin: FreeBSD /usr/src/lib/msun/src/e_coshf.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 coshf(float x)
 {
        union {float f; uint32_t i;} u = {.f = x};
-       uint32_t ix;
+       uint32_t w;
        float t;
 
        /* |x| */
        u.i &= 0x7fffffff;
        x = u.f;
-       ix = u.i;
+       w = u.i;
 
-       /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
-       if (ix < 0x3eb17218) {
-               t = expm1f(x);
-               if (ix < 0x39800000)
+       /* |x| < log(2) */
+       if (w < 0x3f317217) {
+               if (w < 0x3f800000 - (12<<23)) {
+                       FORCE_EVAL(x + 0x1p120f);
                        return 1;
+               }
+               t = expm1f(x);
                return 1 + t*t/(2*(1+t));
        }
 
-       /* |x| in [0.5*ln2,9], return (exp(|x|)+1/exp(|x|))/2; */
-       if (ix < 0x41100000) {
+       /* |x| < log(FLT_MAX) */
+       if (w < 0x42b17217) {
                t = expf(x);
-               return 0.5f*t + 0.5f/t;
+               return 0.5f*(t + 1/t);
        }
 
-       /* |x| in [9, log(maxfloat)] return 0.5f*exp(|x|) */
-       if (ix < 0x42b17217)
-               return 0.5f*expf(x);
-
-       /* |x| in [log(maxfloat), overflowthresold] */
-       if (ix <= 0x42b2d4fc)
-               return __expo2f(x);
-
-       /* |x| > overflowthresold or nan */
-       x *= 0x1p127f;
-       return x;
+       /* |x| > log(FLT_MAX) or nan */
+       t = __expo2f(x);
+       return t;
 }