diff options
Diffstat (limited to 'libm/src/s_cbrtf.c')
-rw-r--r-- | libm/src/s_cbrtf.c | 79 |
1 files changed, 0 insertions, 79 deletions
diff --git a/libm/src/s_cbrtf.c b/libm/src/s_cbrtf.c deleted file mode 100644 index 75569a2..0000000 --- a/libm/src/s_cbrtf.c +++ /dev/null @@ -1,79 +0,0 @@ -/* s_cbrtf.c -- float version of s_cbrt.c. - * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. - * Debugged and optimized by Bruce D. Evans. - */ - -/* - * ==================================================== - * 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. - * ==================================================== - */ - -#ifndef lint -static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_cbrtf.c,v 1.12 2005/12/13 20:17:23 bde Exp $"; -#endif - -#include "math.h" -#include "math_private.h" - -/* cbrtf(x) - * Return cube root of x - */ -static const unsigned - B1 = 709958130, /* B1 = (127-127.0/3-0.03306235651)*2**23 */ - B2 = 642849266; /* B2 = (127-127.0/3-24/3-0.03306235651)*2**23 */ - -static const float -C = 5.4285717010e-01, /* 19/35 = 0x3f0af8b0 */ -D = -7.0530611277e-01, /* -864/1225 = 0xbf348ef1 */ -E = 1.4142856598e+00, /* 99/70 = 0x3fb50750 */ -F = 1.6071428061e+00, /* 45/28 = 0x3fcdb6db */ -G = 3.5714286566e-01; /* 5/14 = 0x3eb6db6e */ - -float -cbrtf(float x) -{ - float r,s,t,w; - int32_t hx; - u_int32_t sign; - u_int32_t high; - - GET_FLOAT_WORD(hx,x); - sign=hx&0x80000000; /* sign= sign(x) */ - hx ^=sign; - if(hx>=0x7f800000) return(x+x); /* cbrt(NaN,INF) is itself */ - if(hx==0) - return(x); /* cbrt(0) is itself */ - - /* rough cbrt to 5 bits */ - if(hx<0x00800000) { /* subnormal number */ - SET_FLOAT_WORD(t,0x4b800000); /* set t= 2**24 */ - t*=x; - GET_FLOAT_WORD(high,t); - SET_FLOAT_WORD(t,sign|((high&0x7fffffff)/3+B2)); - } else - SET_FLOAT_WORD(t,sign|(hx/3+B1)); - - /* new cbrt to 23 bits */ - r=t*t/x; - s=C+r*t; - t*=G+F/(s+E+D/s); - - /* chop t to 12 bits and make it larger in magnitude than cbrt(x) */ - GET_FLOAT_WORD(high,t); - SET_FLOAT_WORD(t,(high&0xfffff000)+0x00001000); - - /* one step Newton iteration to 24 bits with error less than 0.667 ulps */ - s=t*t; /* t*t is exact */ - r=x/s; - w=t+t; - r=(r-t)/(w+r); /* r-t is exact */ - t=t+t*r; - - return(t); -} |