diff options
Diffstat (limited to 'libm/powerpc/classic/s_logb.c')
| -rw-r--r-- | libm/powerpc/classic/s_logb.c | 107 |
1 files changed, 0 insertions, 107 deletions
diff --git a/libm/powerpc/classic/s_logb.c b/libm/powerpc/classic/s_logb.c deleted file mode 100644 index 81daa412e..000000000 --- a/libm/powerpc/classic/s_logb.c +++ /dev/null @@ -1,107 +0,0 @@ -/******************************************************************************* -* * -* File logb.c, * -* Functions logb. * -* Implementation of logb for the PowerPC. * -* * -* Copyright © 1991 Apple Computer, Inc. All rights reserved. * -* * -* Written by Ali Sazegari, started on June 1991, * -* * -* August 26 1991: removed CFront Version 1.1d17 warnings. * -* August 27 1991: no errors reported by the test suite. * -* November 11 1991: changed CLASSEXTENDED to the macro CLASSIFY and * -* + or - infinity to constants. * -* November 18 1991: changed the macro CLASSIFY to CLASSEXTENDEDint to * -* improve performance. * -* February 07 1992: changed bit operations to macros ( object size is * -* unchanged ). * -* September24 1992: took the "#include support.h" out. * -* December 03 1992: first rs/6000 port. * -* August 30 1992: set the divide by zero for the zero argument case. * -* October 05 1993: corrected the environment. * -* October 17 1994: replaced all environmental functions with __setflm. * -* May 28 1997: made speed improvements. * -* April 30 2001: forst mac os x port using gcc. * -* * -******************************************************************************** -* The C math library offers a similar function called "frexp". It is * -* different in details from logb, but similar in spirit. This current * -* implementation of logb follows the recommendation in IEEE Standard 854 * -* which is different in its handling of denormalized numbers from the IEEE * -* Standard 754. * -*******************************************************************************/ - -#include <math.h> -#include <endian.h> - -typedef union - { - struct { -#if (__BYTE_ORDER == __BIG_ENDIAN) - unsigned long int hi; - unsigned long int lo; -#else - unsigned long int lo; - unsigned long int hi; -#endif - } words; - double dbl; - } DblInHex; - -static const double twoTo52 = 4.50359962737049600e15; // 0x1p52 -static const double klTod = 4503601774854144.0; // 0x1.000008p52 -static const unsigned long int signMask = 0x80000000ul; -static const DblInHex minusInf = {{ 0xFFF00000, 0x00000000 }}; - - -/******************************************************************************* -******************************************************************************** -* L O G B * -******************************************************************************** -*******************************************************************************/ - -libm_hidden_proto(logb) -double logb ( double x ) - { - DblInHex xInHex; - long int shiftedExp; - - xInHex.dbl = x; - shiftedExp = ( xInHex.words.hi & 0x7ff00000UL ) >> 20; - - if ( shiftedExp == 2047 ) - { // NaN or INF - if ( ( ( xInHex.words.hi & signMask ) == 0 ) || ( x != x ) ) - return x; // NaN or +INF return x - else - return -x; // -INF returns +INF - } - - if ( shiftedExp != 0 ) // normal number - shiftedExp -= 1023; // unbias exponent - - else if ( x == 0.0 ) - { // zero - xInHex.words.hi = 0x0UL; // return -infinity - return ( minusInf.dbl ); - } - - else - { // subnormal number - xInHex.dbl *= twoTo52; // scale up - shiftedExp = ( xInHex.words.hi & 0x7ff00000UL ) >> 20; - shiftedExp -= 1075; // unbias exponent - } - - if ( shiftedExp == 0 ) // zero result - return ( 0.0 ); - - else - { // nonzero result - xInHex.dbl = klTod; - xInHex.words.lo += shiftedExp; - return ( xInHex.dbl - klTod ); - } - } -libm_hidden_def(logb) |