boot/freeldr/freeldr/arch/amd64/int386.S

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2002  Brian Palmer  <brianp@sginet.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License along
  16  *  with this program; if not, write to the Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <asm.inc>
  21 #include <arch/pc/x86common.h>
  22 #include <arch/pc/pcbios.h>
  23 .code64
  24
  25 EXTERN CallRealMode:PROC
  26
  27 /* int Int386(int ivec<ecx>, REGS* in<rdx>, REGS* out<r8>); */
  28 PUBLIC Int386
  29 Int386:
  30
  31     /* Save home registers */
  32     mov r11, rsp
  33     mov qword ptr [r11 + 8], rcx
  34     mov qword ptr [r11 + 16], rdx
  35     mov qword ptr [r11 + 24], r8
  36
  37     /* Save non-volatile registers */
  38     push rbx
  39     push rbp
  40     push rsi
  41     push rdi
  42
  43     /* Alloc stack space for home registers */
  44     sub rsp, 40
  45     //.ENDPROLOG
  46
  47 int386_2:
  48     /* Copy the int vector to shared memory */
  49     mov dword ptr [BSS_IntVector], ecx
  50
  51     /* Copy input registers */
  52     mov rsi, rdx
  53     mov rdi, BSS_RegisterSet
  54     mov rcx, REGS_SIZE / 4
  55     rep movsd
  56
  57     xor rax, rax
  58     xor rbx, rbx
  59     xor rcx, rcx
  60     xor rdx, rdx
  61     xor rbp, rbp
  62     xor rsi, rsi
  63     xor rdi, rdi
  64
  65     /* Set the function ID and call real mode */
  66     mov bx, FNID_Int386
  67     call CallRealMode
  68
  69     /* Copy output registers */
  70     mov rsi, BSS_RegisterSet
  71     mov rdi, [r11 + 24]
  72     mov rcx, REGS_SIZE / 4
  73     rep movsd
  74
  75     /* cleanup and return */
  76     add rsp, 40
  77     pop rdi
  78     pop rsi
  79     pop rbp
  80     pop rbx
  81     ret
  82
  83 END