libsyscall/custom/__fork.s

   1 /*
   2  * Copyright (c) 1999-2010 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_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. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1992 NeXT Computer, Inc.  All rights reserved.
  29  *
  30  *      File:   libc/ppc/sys/fork.s
  31  *
  32  * HISTORY
  33  * 18-Nov-92  Ben Fathi (benf@next.com)
  34  *      Created from M88K sources
  35  *
  36  * 11-Jan-92  Peter King (king@next.com)
  37  *      Created from M68K sources
  38  */
  39
  40 /*
  41  * All of the asm stubs in this file have been adjusted so the pre/post
  42  * fork handlers and dyld fixup are done in C inside Libc. As such, Libc
  43  * expects the __fork asm to fix up the return code to be -1, 0 or pid
  44  * and errno if needed.
  45  */
  46
  47 #include "SYS.h"
  48
  49 #if defined(__i386__)
  50
  51 LEAF(___fork, 0)
  52         subl  $28, %esp   // Align the stack, with 16 bytes of extra padding that we'll need
  53
  54         movl    $ SYS_fork,%eax;        // code for fork -> eax
  55         UNIX_SYSCALL_TRAP               // do the system call
  56         jnc     L1                      // jump if CF==0
  57
  58         CALL_EXTERN(tramp_cerror)
  59         movl    $-1,%eax
  60         addl    $28, %esp   // restore the stack
  61         ret
  62
  63 L1:
  64         orl     %edx,%edx       // CF=OF=0,  ZF set if zero result
  65         jz      L2              // parent, since r1 == 0 in parent, 1 in child
  66
  67         //child here...
  68         xorl    %eax,%eax       // zero eax
  69         REG_TO_EXTERN(%eax, __current_pid);
  70 L2:
  71         addl    $28, %esp   // restore the stack
  72         // parent ends up here skipping child portion
  73         ret
  74
  75 #elif defined(__x86_64__)
  76
  77 LEAF(___fork, 0)
  78         subq  $24, %rsp   // Align the stack, plus room for local storage
  79
  80         movl    $ SYSCALL_CONSTRUCT_UNIX(SYS_fork),%eax; // code for fork -> rax
  81         UNIX_SYSCALL_TRAP               // do the system call
  82         jnc     L1                      // jump if CF==0
  83
  84         movq    %rax, %rdi
  85         CALL_EXTERN(_cerror)
  86         movq    $-1, %rax
  87         addq    $24, %rsp   // restore the stack
  88         ret
  89
  90 L1:
  91         orl     %edx,%edx       // CF=OF=0,  ZF set if zero result
  92         jz      L2              // parent, since r1 == 0 in parent, 1 in child
  93
  94         //child here...
  95         xorq    %rax, %rax
  96         PICIFY(__current_pid)
  97         movl    %eax,(%r11)
  98 L2:
  99         // parent ends up here skipping child portion
 100         addq    $24, %rsp   // restore the stack
 101         ret
 102
 103 #else
 104 #error Unsupported architecture
 105 #endif