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Diffstat (limited to 'newlib/libm/common/sf_logb.c')
| -rw-r--r-- | newlib/libm/common/sf_logb.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/newlib/libm/common/sf_logb.c b/newlib/libm/common/sf_logb.c new file mode 100644 index 00000000000..6e67637fe92 --- /dev/null +++ b/newlib/libm/common/sf_logb.c @@ -0,0 +1,48 @@ +/* sf_logb.c -- float version of s_logb.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 "fdlibm.h" + +#ifdef __STDC__ + float logbf(float x) +#else + float logbf(x) + float x; +#endif +{ + __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); +} + +#ifdef _DOUBLE_IS_32BITS + +#ifdef __STDC__ + double logb(double x) +#else + double logb(x) + double x; +#endif +{ + return (double) logbf((float) x); +} + +#endif /* defined(_DOUBLE_IS_32BITS) */ |