glibc/sysdeps/ieee754/flt-32/s_ceilf.c
Joseph Myers ac2cc6f021 Do not raise "inexact" from generic ceil (bug 15479).
C99 and C11 allow but do not require ceil, floor, round and trunc to
raise the "inexact" exception for noninteger arguments.  TS 18661-1
requires that this exception not be raised by these functions.  This
aligns them with general IEEE semantics, where "inexact" is only
raised if the final step of rounding the infinite-precision result to
the result type is inexact; for these functions, the
infinite-precision integer result is always representable in the
result type, so "inexact" should never be raised.

The generic implementations of ceil, floor and round functions contain
code to force "inexact" to be raised.  This patch removes it for ceil
functions to align them with TS 18661-1 in this regard.  Note that
some architecture-specific versions may still raise "inexact", so the
tests are not updated and the bug is not yet fixed.

Tested for x86_64, x86 and mips64.

	[BZ #15479]
	* sysdeps/ieee754/dbl-64/s_ceil.c: Do not mention "inexact"
	exception in comment.
	(huge): Remove variable.
	(__ceil): Do not force "inexact" exception.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_ceil.c: Do not mention
	"inexact" exception in comment.
	(huge): Remove variable.
	(__ceil): Do not force "inexact" exception.
	* sysdeps/ieee754/flt-32/s_ceilf.c (huge): Remove variable.
	(__ceilf): Do not force "inexact" exception.
	* sysdeps/ieee754/ldbl-128/s_ceill.c: Do not mention "inexact"
	exception in comment.
	(huge): Remove variable.
	(__ceill): Do not force "inexact" exception.
2016-05-24 17:42:10 +00:00

49 lines
1.1 KiB
C

/* s_ceilf.c -- float version of s_ceil.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>
float
__ceilf(float x)
{
int32_t i0,j0;
u_int32_t i;
GET_FLOAT_WORD(i0,x);
j0 = ((i0>>23)&0xff)-0x7f;
if(j0<23) {
if(j0<0) {
/* return 0*sign(x) if |x|<1 */
if(i0<0) {i0=0x80000000;}
else if(i0!=0) { i0=0x3f800000;}
} else {
i = (0x007fffff)>>j0;
if((i0&i)==0) return x; /* x is integral */
if(i0>0) i0 += (0x00800000)>>j0;
i0 &= (~i);
}
} else {
if(__builtin_expect(j0==0x80, 0)) return x+x; /* inf or NaN */
else return x; /* x is integral */
}
SET_FLOAT_WORD(x,i0);
return x;
}
#ifndef __ceilf
weak_alias (__ceilf, ceilf)
#endif