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Annotation of objc/objc-moninit-m68k.c, 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 1.0 (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: #ifdef SHLIB
        !            25: #import "shlib.h"
        !            26: #undef moninitobjc
        !            27: #endif
        !            28: 
        !            29: #ifndef __m68k__
        !            30: #error "this is m68k machine dependent"
        !            31: #endif
        !            32: 
        !            33: #include <mach/mach.h>
        !            34: 
        !            35: /*
        !            36:  * objc_exitPoints is a private_extern defined in the objective-C messager
        !            37:  * which is a zero terminated table of a list of text lables to write
        !            38:  * instructions which will cause the objective-C messager to then call
        !            39:  * moncount for each message it dispatches.  The instruction at each of these
        !            40:  * text lables is a "jmp a0@" instruction.  The objective-C messager has
        !            41:  * allocated space after each of these instructions for moninitobjc to write
        !            42:  * the instructions to call moncount for each message it dispatches.
        !            43:  * 
        !            44:  * The instructions written over the "jmp a0@" and the allocated space after
        !            45:  * it are:
        !            46:  * exitPoint1: jmp     a0@
        !            47:  *             | replace with the following instructions
        !            48:  *             movel   a0,sp@-
        !            49:  *             movel   a1,sp@-
        !            50:  *             movel   a0,sp@-
        !            51:  *             movel   sp@(12),sp@-
        !            52:  *             jsr     moncount
        !            53:  *             addl    #8,sp
        !            54:  *             movel   sp@+,a1
        !            55:  *             movel   sp@+,a0
        !            56:  *             jmp     a0@
        !            57:  */
        !            58: extern unsigned long objc_exitPoints[];
        !            59: 
        !            60: /*
        !            61:  * objc_entryPoints is a private_extern defined in the objective-C messager
        !            62:  * which is a zero terminated table of a list of text lables that should not
        !            63:  * have a call inserted to moncount in their shared library branch table slot.
        !            64:  */
        !            65: extern unsigned long objc_entryPoints[];
        !            66: 
        !            67: /*
        !            68:  * moninitobjc() is a machine dependent routine that causes objective-C
        !            69:  * messager to call moncount() for each message it sends.
        !            70:  */
        !            71: unsigned long *
        !            72: moninitobjc(
        !            73: unsigned long moncount_addr)
        !            74: {
        !            75:     unsigned long i, min, max;
        !            76:     char *p;
        !            77:     kern_return_t r;
        !            78: 
        !            79:        if(objc_exitPoints[0] == 0)
        !            80:            return(objc_entryPoints);
        !            81: 
        !            82:        /*
        !            83:         * Determine the area to vm_protect() for writing the code.
        !            84:         */
        !            85:        min = 0xffffffff;
        !            86:        max = 0;
        !            87:        for(i = 0; objc_exitPoints[i] != 0; i++){
        !            88:            if(objc_exitPoints[i] < min)
        !            89:                min = objc_exitPoints[i];
        !            90:            if(objc_exitPoints[i] > max)
        !            91:                max = objc_exitPoints[i];
        !            92:        }
        !            93:        max += 24;
        !            94: 
        !            95:        if((r = vm_protect(task_self(), (vm_address_t)min, (vm_size_t)(max-min),
        !            96:                           FALSE, VM_PROT_READ | VM_PROT_WRITE |
        !            97:                           VM_PROT_EXECUTE)) != KERN_SUCCESS)
        !            98:            return(objc_entryPoints);
        !            99: 
        !           100:        /*
        !           101:         * Write in the code to call moncount.
        !           102:         */
        !           103:        for(i = 0; objc_exitPoints[i] != 0; i++){
        !           104:            p = (char *)(objc_exitPoints[i]);
        !           105:            /* movel a0,sp@- */
        !           106:            *p++ = 0x2f;
        !           107:            *p++ = 0x08;
        !           108:            /* movel a1,sp@- */
        !           109:            *p++ = 0x2f;
        !           110:            *p++ = 0x09;
        !           111:            /* movel a0,sp@- */
        !           112:            *p++ = 0x2f;
        !           113:            *p++ = 0x08;
        !           114:            /* movel sp@(12),sp@- */
        !           115:            *p++ = 0x2f;
        !           116:            *p++ = 0x2f;
        !           117:            *p++ = 0x00;
        !           118:            *p++ = 0x0c;
        !           119:            /* jsr      moncount */
        !           120:            *p++ = 0x4e;
        !           121:            *p++ = 0xb9;
        !           122:            *p++ = (moncount_addr >> 24) & 0xff;
        !           123:            *p++ = (moncount_addr >> 16) & 0xff;
        !           124:            *p++ = (moncount_addr >>  8) & 0xff;
        !           125:            *p++ = (moncount_addr) & 0xff;
        !           126:            /* addl #8,sp */
        !           127:            *p++ = 0x50;
        !           128:            *p++ = 0x8f;
        !           129:            /* movel sp@+,a1 */
        !           130:            *p++ = 0x22;
        !           131:            *p++ = 0x5f;
        !           132:            /* movel sp@+,a0 */
        !           133:            *p++ = 0x20;
        !           134:            *p++ = 0x5f;
        !           135:            /* jmp a0@ */
        !           136:            *p++ = 0x4e;
        !           137:            *p++ = 0xd0;
        !           138:        }
        !           139:        /*
        !           140:         * The text cache for the this code now needs to be flushed since
        !           141:         * it was just written on so that future calls will get the new
        !           142:         * instructions.
        !           143:        cache_flush(min, max-min);
        !           144:         */
        !           145:        asm("trap #2");
        !           146: 
        !           147:        return(objc_entryPoints);
        !           148: }

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