lib/setjmp/setjmp.asm

   1 ;  ZeX/OS
   2 ;  Copyright (C) 2007  Tomas 'ZeXx86' Jedrzejek (zexx86@gmail.com)
   3 ;
   4 ;  This program is free software: you can redistribute it and/or modify
   5 ;  it under the terms of the GNU General Public License as published by
   6 ;  the Free Software Foundation, either version 3 of the License, or
   7 ;  (at your option) any later version.
   8 ;
   9 ;  This program is distributed in the hope that it will be useful,
  10 ;  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 ;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 ;  GNU General Public License for more details.
  13 ;
  14 ;  You should have received a copy of the GNU General Public License
  15 ;  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 %macro  IMP 1
  19 %ifdef UNDERBARS
  20         EXTERN _%1
  21         %define %1 _%1
  22 %else
  23         EXTERN %1
  24 %endif
  25 %endmacro
  26
  27 %macro  EXP     1
  28         GLOBAL $_%1
  29         $_%1:
  30         GLOBAL $%1
  31         $%1:
  32 %endmacro
  33
  34 SECTION .text
  35
  36 EXP setjmp
  37         push ebx
  38                 mov ebx,[8 + esp]
  39
  40                 mov [0 + ebx],edi       ; buf->edi == 0(ebx) == EDI
  41                 mov [4 + ebx],esi       ; buf->esi == 4(ebx) == ESI
  42                 mov [8 + ebx],ebp       ; buf->ebp == 8(ebx) == EBP
  43
  44                 mov [20 + ebx],edx      ; buf->edx == 20(ebx) == EDX
  45                 mov [24 + ebx],ecx      ; buf->ecx == 24(ebx) == ECX
  46                 mov [28 + ebx],eax      ; buf->eax == 28(ebx) == EAX
  47
  48 ; use EBX value saved on stack; not the current value
  49                 mov eax,[esp]
  50                 mov [16 + ebx],eax      ; buf->ebx == 16(ebx) == EBX
  51
  52 ; use ESP value after RET; not the current value
  53                 lea eax,[8 + esp]
  54                 mov [12 + ebx],eax      ; buf->esp == 32(ebx) == ESP
  55
  56 ; use return address of this routine (EIP value saved on stack);
  57 ; not the current value
  58                 mov eax,[4 + esp]
  59                 mov [32 + ebx],eax      ; buf->eip == 36(ebx) == EIP
  60
  61 ; none of the PUSH or MOV instructions changed EFLAGS!
  62                 pushf
  63                 pop dword [36 + ebx]    ; buf->eflags == 40(ebx) == EFLAGS
  64         pop ebx
  65         xor eax,eax
  66         ret