Annotation of kernel/machdep/i386/longlong.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            24: 
        !            25: /*
        !            26:  * Routines to optimize some forms of long-long math.
        !            27:  *
        !            28:  * Copyright (c) 1992 NeXT, Inc.
        !            29:  *
        !            30:  * HISTORY
        !            31:  *
        !            32:  *  1Nov92 Brian Pinkerton at NeXT
        !            33:  *     Created.
        !            34:  */
        !            35: 
        !            36: static inline void
        !            37: llp_div_l(unsigned long long *ll, unsigned int divisor, unsigned int *remain)
        !            38: {
        !            39:     unsigned int *msw, *lsw;
        !            40:     unsigned int quo, rem1, rem2;
        !            41:     union foo {
        !            42:        unsigned long long ll;
        !            43:        unsigned int i[2];
        !            44:     } *llp;
        !            45: 
        !            46:     llp = (union foo *) ll;
        !            47:     lsw = &llp->i[0];
        !            48:     msw = &llp->i[1];
        !            49: 
        !            50:     asm("divl %2"
        !            51:        : "=a" (quo), "=d" (rem1)
        !            52:        : "rm" (divisor), "0" (*msw), "1" (0));
        !            53: 
        !            54:     *msw = quo;
        !            55: 
        !            56:     asm("divl %2"
        !            57:        : "=a" (quo), "=d" (*remain)
        !            58:        : "rm" (divisor), "0" (*lsw), "1" (rem1));
        !            59: 
        !            60:     *lsw = quo;
        !            61: }
        !            62: 
        !            63: 
        !            64: static inline unsigned int
        !            65: ll_div_l(unsigned long long ll, unsigned int divisor)
        !            66: {
        !            67:     unsigned int *msw, *lsw;
        !            68:     unsigned int quo, rem1;
        !            69:     union foo {
        !            70:        unsigned long long ll;
        !            71:        unsigned int i[2];
        !            72:     } *llp;
        !            73: 
        !            74:     llp = (union foo *) ≪
        !            75:     lsw = &llp->i[0];
        !            76:     msw = &llp->i[1];
        !            77: 
        !            78:     asm("divl %2"
        !            79:        : "=a" (quo), "=d" (rem1)
        !            80:        : "rm" (divisor), "0" (*msw), "1" (0));
        !            81: 
        !            82:     asm("divl %1"
        !            83:        : "=a" (quo)
        !            84:        : "rm" (divisor), "0" (*lsw), "d" (rem1));
        !            85: 
        !            86:     return quo;
        !            87: }

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