expm1l.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 "expm1l.s"
#include "libm.h"
LIBM_ANSI_PRAGMA_WEAK(expm1l,function)
#include "libm_synonyms.h"
.data
.align 4
ln2_hi: .long 0xd1d00000, 0xb17217f7, 0x00003ffe
ln2_lo: .long 0x4c67fc0d, 0x8654361c, 0x0000bfce
ENTRY(expm1l)
movl 12(%esp),%ecx / cx <--sign&bexp(x)
movl %ecx,%eax / ax <--sign&bexp(x)
andl $0x00007fff,%ecx / ecx <-- zero_xtnd(bexp(x))
cmpl $0x00003ffe,%ecx / Is |x| < ln(2)?
jb .shortcut / If so, take a shortcut.
je .check_tail / |x| may be only slightly < ln(2)
cmpl $0x00007fff,%ecx / bexp(|x|) = bexp(INF)?
je .not_finite / if so, x is not finite
andl $0x0000ffff,%eax / eax <-- sign&bexp(x)
cmpl $0x0000c006,%eax / x <= -128?
jae 1f / if so, simply return -1
cmpl $0x0000400d,%ecx / |x| < 16384 = 2^14?
jb .finite_non_special / if so, proceed with argument reduction
fldt 4(%esp) / x >= 16384; x
fld1 / 1, x
fscale / +Inf, x
fstp %st(1) / +Inf
ret
.finite_non_special: / -128 < x < -ln(2) || ln(2) < x < 2^14
fldt 4(%esp) / x
fld %st(0) / x, x
fldl2e / log2(e), x, x
fmulp / z := x*log2(e), x
frndint / [z], x
fst %st(2) / [z], x, [z]
PIC_SETUP(1)
fldt PIC_L(ln2_hi) / ln2_hi, [z], x, [z]
fmulp / [z]*ln2_hi, x, [z]
fsubrp %st,%st(1) / x-[z]*ln2_hi, [z]
fldt PIC_L(ln2_lo) / ln2_lo, x-[z]*ln2_hi, [z]
PIC_WRAPUP
fmul %st(2),%st / [z]*ln2_lo, x-[z]*ln2_hi, [z]
fsubrp %st,%st(1) / r := x-[z]*ln(2), [z]
fldl2e / log2(e), r, [z]
fmulp / f := r*log2(e), [z]
f2xm1 / 2^f-1,[z]
fld1 / 1, 2^f-1, [z]
faddp %st,%st(1) / 2^f, [z]
fscale / e^x, [z]
fstp %st(1) / e^x
fld1 / 1, e^x
fsubrp %st,%st(1) / e^x-1
ret
.check_tail:
movl 8(%esp),%ecx / ecx <-- hi_32(sgnfcnd(x))
cmpl $0xb17217f7,%ecx / Is |x| < ln(2)?
ja .finite_non_special
jb .shortcut
movl 4(%esp),%edx / edx <-- lo_32(x)
cmpl $0xd1cf79ab,%edx / Is |x| slightly < ln(2)?
ja .finite_non_special / branch if |x| slightly > ln(2)
.shortcut:
/ Here, |x| < ln(2), so |z| = |x/ln(2)| < 1,
/ whence z is in f2xm1's domain.
fldt 4(%esp) / x
fldl2e / log2(e), x
fmulp / z := x*log2(e)
f2xm1 / 2^(x*log2(e))-1 = e^x-1
ret
.not_finite:
movl 8(%esp),%ecx / ecx <-- hi_32(sgnfcnd(x))
cmpl $0x80000000,%ecx / hi_32(|x|) = hi_32(INF)?
jne .NaN_or_pinf / if not, x is NaN
movl 4(%esp),%edx / edx <-- lo_32(x)
cmpl $0,%edx / lo_32(x) = 0?
jne .NaN_or_pinf / if not, x is NaN
movl 12(%esp),%eax / ax <-- sign&bexp((x))
andl $0x00008000,%eax / here, x is infinite, but +/-?
jz .NaN_or_pinf / branch if x = +INF
1:
fld1 / Here, x = -inf, so return -1
fchs
ret
.NaN_or_pinf:
/ Here, x = NaN or +inf, so load x and return immediately.
fldt 4(%esp)
ret
.align 4
SET_SIZE(expm1l)