runtime/Auto.subproj/objc-auto-i386.s

   1 /*
   2  * Copyright (c) 2004, 2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <TargetConditionals.h>
  25
  26 #if __i386__  &&  !TARGET_OS_IPHONE  &&  !TARGET_OS_WIN32
  27
  28 /*
  29     This file defines the non-GC variants of objc_assign_* on a dedicated
  30     page in the (__DATA,__data) section. At load time under GC, each
  31     routine is overwritten with a jump to its GC variant. It is necessary
  32     for these routines to exist on a dedicated page for vm_protect to
  33     work properly in the GC case. The page exists in the data segment to
  34     reduce the kernel's page table overhead.
  35
  36     Note: To avoid wasting more space than necessary at runtime, this file
  37     must not contain anything other than the objc_assign_* routines.
  38 */
  39
  40 .section __IMPORT, __objctext, regular, pure_instructions + self_modifying_code
  41
  42 .align 12   // align to page boundary
  43
  44 // id objc_assign_ivar(id value, id dest, ptrdiff_t offset);
  45 .globl  _objc_assign_ivar
  46 _objc_assign_ivar:
  47     pushl   %ebp
  48     movl    %esp,%ebp
  49     movl    0x08(%ebp),%eax     // value
  50     movl    0x0c(%ebp),%ecx     // dest
  51     movl    0x10(%ebp),%edx     // offset
  52     movl    %eax,(%ecx,%edx)    // return (*(dest + offset) = value);
  53     leave
  54     ret
  55
  56 // id objc_assign_global(id value, id *dest);
  57 .globl  _objc_assign_global
  58 _objc_assign_global:
  59     pushl   %ebp
  60     movl    %esp,%ebp
  61     movl    0x08(%ebp),%eax     // value
  62     movl    0x0c(%ebp),%edx     // dest
  63     movl    %eax,(%edx)         // return (*dest = value);
  64     leave
  65     ret
  66
  67 // id objc_assign_threadlocal(id value, id *dest);
  68 .globl  _objc_assign_threadlocal
  69 _objc_assign_threadlocal:
  70     pushl   %ebp
  71     movl    %esp,%ebp
  72     movl    0x08(%ebp),%eax     // value
  73     movl    0x0c(%ebp),%edx     // dest
  74     movl    %eax,(%edx)         // return (*dest = value);
  75     leave
  76     ret
  77
  78 // As of OS X 10.5, objc_assign_strongCast_non_gc is identical to
  79 // objc_assign_global_non_gc.
  80
  81 // id objc_assign_strongCast(id value, id *dest);
  82 .globl  _objc_assign_strongCast
  83 _objc_assign_strongCast:
  84     pushl   %ebp
  85     movl    %esp,%ebp
  86     movl    0x08(%ebp),%eax     // value
  87     movl    0x0c(%ebp),%edx     // dest
  88     movl    %eax,(%edx)         // return (*dest = value);
  89     leave
  90     ret
  91
  92 // Claim the remainder of the page.
  93 .align 12, 0
  94
  95 #endif