minix/lib/libm/arch/vax/n_scalbn.S

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/*-
* Copyright (c) 2011 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <machine/asm.h>
#include <sys/errno.h>
RCSID("$NetBSD: n_scalbn.S,v 1.4 2013/05/24 12:45:40 martin Exp $")
WEAK_ALIAS(scalbn,_scalbn)
WEAK_ALIAS(ldexp,_scalbn)
WEAK_ALIAS(ldexpf,_scalbnf)
WEAK_ALIAS(ldexpl,_scalbnl)
ENTRY(_scalbnf, 0)
cvtfd 4(%ap), %r0
movl 8(%ap), %r2
jr 1f
ALTENTRY(_scalbnl)
ENTRY(_scalbn, 0)
movd 4(%ap), %r0
movl 12(%ap), %r2
/*
* First see if the result will be within bounds
*/
1: cmpl %r2,$(256+55)
jgeq overflow
cmpl %r2,$-(256+55)
jleq underflow
extzv $7, $9, %r0, %r3 /* extract exponent */
jneq 5f /* 0 * N is still 0 */
cmpw %r3, $-256 /* is this a NAN? */
jgtr 2f /* nope */
ret
2: movzbl %r3, %r3 /* clear sign bit */
addl2 %r2, %r3 /* add to exponent */
jleq underflow /* <= 0? */
3: jbs $8, %r3, overflow /* did exponent overflow? */
insv $7, $8, %r3, %r0 /* replace exponent */
ret
underflow:
clrq %r0 /* return 0.0 */
jr copysign /* or mabye -0.0 */
overflow:
pushl $ERANGE /* overflow */
calls $1, _C_LABEL(infnan) /* possibly signal */
copysign:
jbc $15, 4(%ap), 5f /* if clear, don't set sign-bit */
bisw2 $0x8000, %r0 /* preserve sign-bit */
5:
ret