ilogbl.s revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
.file "ilogbl.s"
#include "libm.h"
LIBM_ANSI_PRAGMA_WEAK(ilogbl,function)
#include "libm_synonyms.h"
#include "xpg6.h"
.data
.align 8
two63: .long 0x0,0x43d00000 / 2**63
ENTRY(ilogbl)
movl 12(%esp),%eax / eax <-- sign and bexp of x
andl $0x00007fff,%eax / eax <-- bexp(x)
jz .bexp_0 / jump iff x is 0 or subnormal
/ here, biased exponent is non-zero
testl $0x80000000,8(%esp) / test msb of hi_32(sgnfcnd(x))
jz .ilogbl_not_finite / jump if unsupported format
cmpl $0x00007fff,%eax
je .ilogbl_not_finite
subl $16383,%eax / unbias exponent by 16383 = 0x3fff
ret
.ilogbl_not_finite:
movl $0x7fffffff,%eax / x is NaN/inf/unsup
jmp 0f
.bexp_0:
movl 8(%esp),%eax / eax <-- hi_32(sgnfcnd(x))
orl 4(%esp),%eax / test whether x is 0
jnz .ilogbl_subnorm / jump iff x is subnormal
movl $0x80000001,%eax / x is +/-0, so return 0x80000001
0:
PIC_SETUP(0)
PIC_G_LOAD(movzwl,__xpg6,ecx)
PIC_WRAPUP
andl $_C99SUSv3_ilogb_0InfNaN_raises_invalid,%ecx
cmpl $0,%ecx
je 1f
fldz
fdivp %st,%st(0) / raise invalid as per SUSv3
1:
ret
.ilogbl_subnorm: / subnormal or pseudo-denormal input
fldt 4(%esp) / push x, setting D-flag
PIC_SETUP(1)
fmull PIC_L(two63) / x*2**63
PIC_WRAPUP
subl $12,%esp
fstpt (%esp)
movl $0x00007fff,%eax
andl 8(%esp),%eax / eax <-- sign and bexp of x*2**63
subl $16445,%eax / unbias it by (16,383 + 63)
addl $12,%esp
ret
.align 4
SET_SIZE(ilogbl)