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 #ifdef __i386__
  25
  26 /*
  27     This file defines the non-GC variants of objc_assign_* on a dedicated
  28     page in the (__DATA,__data) section. At load time under GC, each
  29     routine is overwritten with a jump to its GC variant. It is necessary
  30     for these routines to exist on a dedicated page for vm_protect to
  31     work properly in the GC case. The page exists in the data segment to
  32     reduce the kernel's page table overhead.
  33
  34     Note: To avoid wasting more space than necessary at runtime, this file
  35     must not contain anything other than the objc_assign_* routines.
  36 */
  37
  38 .section __IMPORT, __objctext, regular, pure_instructions + self_modifying_code
  39
  40 .align 12   // align to page boundary
  41
  42 LNonGCAssigns$Begin:
  43
  44 // id objc_assign_ivar(id value, id dest, ptrdiff_t offset);
  45 .globl  _objc_assign_ivar
  46 _objc_assign_ivar:
  47     pushl   %ebp
  48     movl    %esp,%ebp
  49     movl    0x08(%ebp),%eax     // value
  50     movl    0x0c(%ebp),%ecx     // dest
  51     movl    0x10(%ebp),%edx     // offset
  52     movl    %eax,(%ecx,%edx)    // return (*(dest + offset) = value);
  53     leave
  54     ret
  55
  56 // id objc_assign_global(id value, id *dest);
  57 .globl  _objc_assign_global
  58 _objc_assign_global:
  59     pushl   %ebp
  60     movl    %esp,%ebp
  61     movl    0x08(%ebp),%eax     // value
  62     movl    0x0c(%ebp),%edx     // dest
  63     movl    %eax,(%edx)         // return (*dest = value);
  64     leave
  65     ret
  66
  67 // As of OS X 10.5, objc_assign_strongCast_non_gc is identical to
  68 // objc_assign_global_non_gc.
  69
  70 // id objc_assign_strongCast(id value, id *dest);
  71 .globl  _objc_assign_strongCast
  72 _objc_assign_strongCast:
  73     pushl   %ebp
  74     movl    %esp,%ebp
  75     movl    0x08(%ebp),%eax     // value
  76     movl    0x0c(%ebp),%edx     // dest
  77     movl    %eax,(%edx)         // return (*dest = value);
  78     leave
  79     ret
  80
  81 LNonGCAssigns$End:
  82
  83 // Claim the remainder of the page.
  84 .set    L$set$assignsSize,LNonGCAssigns$End-LNonGCAssigns$Begin
  85 .space  4096-L$set$assignsSize
  86
  87 #endif