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/* $OpenBSD: ldexp.S,v 1.9 2013/03/28 18:09:38 martynas Exp $ */
/*
* Copyright (c) 1983, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* double ldexp (value, exp)
* double value;
* int exp;
*
* Ldexp returns value*2**exp, if that result is in range.
* If underflow occurs, it returns zero. If overflow occurs,
* it returns a value of appropriate sign and largest
* possible magnitude. In case of either overflow or underflow,
* errno is set to ERANGE. Note that errno is not modified if
* no error occurs.
*/
#include "DEFS.h"
/*
* don't include errno.h, ANSI C says it defines errno.
*
* #include <errno.h>
*/
#define ERANGE 34
.globl _C_LABEL(errno)
STRONG_ALIAS(ldexpl,ldexp)
ENTRY(ldexp, R2)
movd 4(ap),r0 /* fetch "value" */
extzv $7,$8,r0,r2 /* r2 := biased exponent */
jeql 1f /* if zero, done */
addl2 12(ap),r2 /* r2 := new biased exponent */
jleq 2f /* if <= 0, underflow */
cmpl r2,$256 /* otherwise check if too big */
jgeq 3f /* jump if overflow */
insv r2,$7,$8,r0 /* put exponent back in result */
1:
ret
2:
clrd r0
jbr 1f
3:
movd huge,r0 /* largest possible floating magnitude */
jbc $15,4(ap),1f /* jump if argument was positive */
mnegd r0,r0 /* if arg < 0, make result negative */
1:
movl $ ERANGE,_C_LABEL(errno)
ret
.data
huge: .word 0x7fff /* the largest number that can */
.word 0xffff /* be represented in a long floating */
.word 0xffff /* number. This is given in hex in order */
.word 0xffff /* to avoid floating conversions */
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