/*
 * 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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

        .file   "ldivide.s"

/ Double long divide routine.

#include "SYS.h"

        .set    lop,16
        .set    rop,24
        .set    ans,0

        ENTRY(ldivide)
        popl    %eax
        xchgl   %eax,0(%esp)
        pushl   %eax

        pushl   %esi
        pushl   %edi

        movl    lop(%esp),%eax
        movl    lop+4(%esp),%edx

/ the following code is only for compatibility with original ldivide code
        orl     %edx,%edx       / force numerator positive
        jns     .ldiv1
        notl    %edx
        negl    %eax
        sbbl    $0xffffffff,%edx
.ldiv1:
        testl   $0x80000000,rop+4(%esp)
        jz      .ldiv2
        notl    rop+4(%esp)     / force denominator positive
        negl    rop(%esp)
        sbbl    $0xffffffff,rop+4(%esp)
.ldiv2:
/ end of compatibility code

        xorl    %esi,%esi       / initialize remainder to 0
        movl    %esi,%edi
        movl    $64,%ecx        / initialize counter for 64-bits
.div_mod_loop:
        shll    $1,%edi
        rcll    $1,%esi         / remainder * 2
        shll    $1,%eax
        rcll    $1,%edx         / numerator * 2 (also quotient)
        adcl    $0,%edi         / add in any carry from the shift
        subl    rop(%esp),%edi  / subtract denominator from remainder
        sbbl    rop+4(%esp),%esi
        incl    %eax            / turn on quotient bit for now
        jnc     .inc_remainder  / inc didn't affect carry flag
/ can't subtract the denominator from the remainder, add it back
        addl    rop(%esp),%edi
        adcl    rop+4(%esp),%esi
        decl    %eax            / turn quotient bit off
.inc_remainder:
        loop    .div_mod_loop

/ at this point, %edx:%eax has the quotient and %edi:%esi has the remainder
        popl    %edi
        popl    %esi
        movl    %eax,%ecx
        popl    %eax
        movl    %ecx,ans(%eax)
        movl    %edx,ans+4(%eax)
        ret
        SET_SIZE(ldivide)