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2010-02-11 Craig Howland <howland@LGSInnovations.com> 

* libm/common/s_ilogb.c:  Adjust documentation to reflect new returns
        (see next items) and that ilogb() and ilogbf() are C99/POSIX.
        * libm/common/s_ilogb.c (ilogb):  Use C99/POSIX FP_ILOGB0 and
        FP_ILOGBNAN returns for 0 and NAN arguments, respectively, instead of
        the prior -INT_MAX and INT_MAX.  The FP_ILOGBx defines in math.h
        presently match the prior hard-codes, so no functional change is
        actually introduced.  (Not at this time, nor planned, but the values
        are permitted to be different, so subsequent edits of math.h could
        possibly cause a functional change.)
        * libm/common/sf_ilogb.c (ilogbf):  Ditto.
This commit is contained in:
Jeff Johnston 2010-02-11 21:00:33 +00:00
parent 9bb1d645b3
commit 451a8eb09a
3 changed files with 40 additions and 10 deletions
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13
newlib/ChangeLog
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@ -1,3 +1,16 @@
2010-02-11 Craig Howland <howland@LGSInnovations.com>
* libm/common/s_ilogb.c: Adjust documentation to reflect new returns
(see next items) and that ilogb() and ilogbf() are C99/POSIX.
* libm/common/s_ilogb.c (ilogb): Use C99/POSIX FP_ILOGB0 and
FP_ILOGBNAN returns for 0 and NAN arguments, respectively, instead of
the prior -INT_MAX and INT_MAX. The FP_ILOGBx defines in math.h
presently match the prior hard-codes, so no functional change is
actually introduced. (Not at this time, nor planned, but the values
are permitted to be different, so subsequent edits of math.h could
possibly cause a functional change.)
* libm/common/sf_ilogb.c (ilogbf): Ditto.
2010-02-09 Daniel Gutson <dgutson@codesourcery.com>
* libc/machine/arm/arm_asm.h (_ISA_THUMB_2): __ARM_ARCH_7EM__

30
newlib/libm/common/s_ilogb.c
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@ -44,13 +44,24 @@ DESCRIPTION
RETURNS
<<ilogb>> and <<ilogbf>> return the power of two used to form the
floating-point argument. If <[val]> is <<0>>, they return <<-
INT_MAX>> (<<INT_MAX>> is defined in limits.h). If <[val]> is
infinite, or NaN, they return <<INT_MAX>>.
floating-point argument.
If <[val]> is <<0>>, they return <<FP_ILOGB0>>.
If <[val]> is infinite, they return <<INT_MAX>>.
If <[val]> is NaN, they return <<FP_ILOGBNAN>>.
(<<FP_ILOGB0>> and <<FP_ILOGBNAN>> are defined in math.h, but in turn are
defined as INT_MIN or INT_MAX from limits.h. The value of FP_ILOGB0 may be
either INT_MIN or -INT_MAX. The value of FP_ILOGBNAN may be either INT_MAX or
INT_MIN.)
@comment The bugs might not be worth noting, given the mass non-C99/POSIX
@comment behavior of much of the Newlib math library.
@commentBUGS
@commentOn errors, errno is not set per C99 and POSIX requirements even if
@comment(math_errhandling & MATH_ERRNO) is non-zero.
PORTABILITY
Neither <<ilogb>> nor <<ilogbf>> is required by ANSI C or by
the System V Interface Definition (Issue 2). */
C99, POSIX
*/
/* ilogb(double x)
* return the binary exponent of non-zero x
@ -58,8 +69,8 @@ PORTABILITY
* ilogb(inf/NaN) = 0x7fffffff (no signal is raised)
*/
#include "fdlibm.h"
#include <limits.h>
#include "fdlibm.h"
#ifndef _DOUBLE_IS_32BITS
@ -76,7 +87,7 @@ PORTABILITY
hx &= 0x7fffffff;
if(hx<0x00100000) {
if((hx|lx)==0)
return - INT_MAX; /* ilogb(0) = 0x80000001 */
return FP_ILOGB0; /* ilogb(0) = special case error */
else /* subnormal x */
if(hx==0) {
for (ix = -1043; lx>0; lx<<=1) ix -=1;
@ -86,7 +97,10 @@ PORTABILITY
return ix;
}
else if (hx<0x7ff00000) return (hx>>20)-1023;
else return INT_MAX;
#if FP_ILOGBNAN != INT_MAX
else if (hx>0x7ff00000) return FP_ILOGBNAN; /* NAN */
#endif
else return INT_MAX; /* infinite (or, possibly, NAN) */
}
#endif /* _DOUBLE_IS_32BITS */

7
newlib/libm/common/sf_ilogb.c
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@ -13,8 +13,8 @@
* ====================================================
*/
#include "fdlibm.h"
#include <limits.h>
#include "fdlibm.h"
#ifdef __STDC__
int ilogbf(float x)
@ -28,11 +28,14 @@
GET_FLOAT_WORD(hx,x);
hx &= 0x7fffffff;
if(FLT_UWORD_IS_ZERO(hx))
return - INT_MAX; /* ilogb(0) = 0x80000001 */
return FP_ILOGB0; /* ilogb(0) = special case error */
if(FLT_UWORD_IS_SUBNORMAL(hx)) {
for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
return ix;
}
#if FP_ILOGBNAN != INT_MAX
else if (FLT_UWORD_IS_NAN(hx)) return FP_ILOGBNAN; /* NAN */
#endif
else if (!FLT_UWORD_IS_FINITE(hx)) return INT_MAX;
else return (hx>>23)-127;
}