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/*
* 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 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
.ident "@(#)exp2l.s 1.3 06/01/23 SMI"
.file "exp2l.s"
#include "libm.h"
LIBM_ANSI_PRAGMA_WEAK(exp2l,function)
#include "libm_synonyms.h"
ENTRY(exp2l)
movl 16(%rsp),%ecx / cx <--sign&bexp(x)
andl $0x7fff,%ecx / ecx <-- zero_xtnd(bexp(x))
cmpl $0x3fff,%ecx / Is |x| <= 1?
jb .shortcut / If so, take a shortcut.
je .check_tail / |x| may be slightly > 1
.general_case: / Here, |x| > 1 or x is NaN
cmpl $0x7fff,%ecx / bexp(|x|) = bexp(INF)?
je .not_finite / if so, x is not finite
.finite_non_special: / Here, 1 < |x| < INF
fldt 8(%rsp) / push arg
fld %st(0) / duplicate stack top
frndint / [x],x
fucomi %st(1),%st / x integral?
je .x_integral / branch if x integral
fxch / x, [x]
fsub %st(1),%st / x-[x], [x]
f2xm1 / 2**(x-[x])-1, [x]
fld1 / 1,2**(x-[x])-1, [x]
faddp %st,%st(1) / 2**(x-[x]), [x]
fscale / 2**x = 2**(arg), [x]
fstp %st(1)
ret
.x_integral:
fstp %st(0) / ,x
fld1 / 1 = 2**0, x
fscale / 2**(0 + x) = 2**x, x
fstp %st(1) / 2**x
ret
.check_tail:
movl 12(%rsp),%ecx / ecx <-- hi_32(sgnfcnd(x))
cmpl $0x80000000,%ecx / Is |x| <= 1?
ja .finite_non_special
movl 8(%rsp),%edx / edx <-- lo_32(sgnfcnd(x))
cmpl $0x0,%edx / Is |x| slightly > 1?
ja .finite_non_special / branch if |x| slightly > 1
.shortcut:
/ Here, |x| < 1,
/ whence x is in f2xm1's domain.
fldt 8(%rsp) / push x
f2xm1 / 2**x - 1
fld1 / 1,2**x - 1
faddp %st,%st(1) / 2**x
ret
.not_finite:
movl 12(%rsp),%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 8(%rsp),%edx / edx <-- lo_32(x)
cmpl $0,%edx / lo_32(x) = 0?
jne .NaN_or_pinf / if not, x is NaN
movl 16(%rsp),%eax / ax <-- sign&bexp((x))
andl $0x8000,%eax / here, x is infinite, but +/-?
jz .NaN_or_pinf / branch if x = +INF
fldz / Here, x = -inf, so return 0
ret
.NaN_or_pinf:
/ Here, x = NaN or +inf, so load x and return immediately.
fldt 8(%rsp)
ret
.align 16
SET_SIZE(exp2l)
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