/*-
 * 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 1.8 2024/05/07 15:15:31 riastradh Exp $")

WEAK_ALIAS(scalbn,_scalbn)
WEAK_ALIAS(scalbnl,_scalbnl)
WEAK_ALIAS(scalbnf,_scalbnf)
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
END(_scalbnf)

STRONG_ALIAS(_scalbnl, _scalbn)
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 maybe -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
END(_scalbn)