| /* s_scalbnf.c -- float version of s_scalbn.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 <math.h> |
| #include <math_private.h> |
| |
| static const float |
| two25 = 3.355443200e+07, /* 0x4c000000 */ |
| twom25 = 2.9802322388e-08, /* 0x33000000 */ |
| huge = 1.0e+30, |
| tiny = 1.0e-30; |
| |
| float |
| __scalblnf (float x, long int n) |
| { |
| int32_t k,ix; |
| GET_FLOAT_WORD(ix,x); |
| k = (ix&0x7f800000)>>23; /* extract exponent */ |
| if (__builtin_expect(k==0, 0)) { /* 0 or subnormal x */ |
| if ((ix&0x7fffffff)==0) return x; /* +-0 */ |
| x *= two25; |
| GET_FLOAT_WORD(ix,x); |
| k = ((ix&0x7f800000)>>23) - 25; |
| } |
| if (__builtin_expect(k==0xff, 0)) return x+x; /* NaN or Inf */ |
| if (__builtin_expect(n< -50000, 0)) |
| return tiny*copysignf(tiny,x); /*underflow*/ |
| if (__builtin_expect(n> 50000 || k+n > 0xfe, 0)) |
| return huge*copysignf(huge,x); /* overflow */ |
| /* Now k and n are bounded we know that k = k+n does not |
| overflow. */ |
| k = k+n; |
| if (__builtin_expect(k > 0, 1)) /* normal result */ |
| {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;} |
| if (k <= -25) |
| return tiny*copysignf(tiny,x); /*underflow*/ |
| k += 25; /* subnormal result */ |
| SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); |
| return x*twom25; |
| } |
| weak_alias (__scalblnf, scalblnf) |
