diff options
Diffstat (limited to 'sysdeps/ieee754/flt-32/s_logbf.c')
| -rw-r--r-- | sysdeps/ieee754/flt-32/s_logbf.c | 32 |
1 files changed, 18 insertions, 14 deletions
diff --git a/sysdeps/ieee754/flt-32/s_logbf.c b/sysdeps/ieee754/flt-32/s_logbf.c index b6aa0f057d..025c70de7e 100644 --- a/sysdeps/ieee754/flt-32/s_logbf.c +++ b/sysdeps/ieee754/flt-32/s_logbf.c @@ -13,23 +13,27 @@ * ==================================================== */ -#if defined(LIBM_SCCS) && !defined(lint) -static char rcsid[] = "$NetBSD: s_logbf.c,v 1.4 1995/05/10 20:47:51 jtc Exp $"; -#endif - #include <math.h> #include <math_private.h> -float __logbf(float x) +float +__logbf (float x) { - int32_t ix; - GET_FLOAT_WORD(ix,x); - ix &= 0x7fffffff; /* high |x| */ - if(ix==0) return (float)-1.0/fabsf(x); - if(ix>=0x7f800000) return x*x; - if((ix>>=23)==0) /* IEEE 754 logb */ - return -126.0; - else - return (float) (ix-127); + int32_t ix, rix; + + GET_FLOAT_WORD (ix, x); + ix &= 0x7fffffff; /* high |x| */ + if (ix == 0) + return (float) -1.0 / fabsf (x); + if (ix >= 0x7f800000) + return x * x; + if (__builtin_expect ((rix = ix >> 23) == 0, 0)) + { + /* POSIX specifies that denormal number is treated as + though it were normalized. */ + int m = (ix == 0) ? 0 : __builtin_clz (ix); + return -126.0 + (float)(8 - m); + } + return (float) (rix - 127); } weak_alias (__logbf, logbf) |