arch/i386/lib/bios.h

   1 /*
   2  * (C) Copyright 2002
   3  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  */
  23
  24 #ifndef _BIOS_H_
  25 #define _BIOS_H_
  26
  27 #define OFFS_ES      0     /* 16bit */
  28 #define OFFS_GS      2     /* 16bit */
  29 #define OFFS_DS      4     /* 16bit */
  30 #define OFFS_EDI     6     /* 32bit */
  31 #define OFFS_DI      6     /* low 16 bits of EDI */
  32 #define OFFS_ESI     10    /* 32bit */
  33 #define OFFS_SI      10    /* low 16 bits of ESI */
  34 #define OFFS_EBP     14    /* 32bit */
  35 #define OFFS_BP      14    /* low 16 bits of EBP */
  36 #define OFFS_ESP     18    /* 32bit */
  37 #define OFFS_SP      18    /* low 16 bits of ESP */
  38 #define OFFS_EBX     22    /* 32bit */
  39 #define OFFS_BX      22    /* low 16 bits of EBX */
  40 #define OFFS_BL      22    /* low  8 bits of BX */
  41 #define OFFS_BH      23    /* high 8 bits of BX */
  42 #define OFFS_EDX     26    /* 32bit */
  43 #define OFFS_DX      26    /* low 16 bits of EBX */
  44 #define OFFS_DL      26    /* low  8 bits of BX */
  45 #define OFFS_DH      27    /* high 8 bits of BX */
  46 #define OFFS_ECX     30    /* 32bit */
  47 #define OFFS_CX      30    /* low 16 bits of EBX */
  48 #define OFFS_CL      30    /* low  8 bits of BX */
  49 #define OFFS_CH      31    /* high 8 bits of BX */
  50 #define OFFS_EAX     34    /* 32bit */
  51 #define OFFS_AX      34    /* low 16 bits of EBX */
  52 #define OFFS_AL      34    /* low  8 bits of BX */
  53 #define OFFS_AH      35    /* high 8 bits of BX */
  54 #define OFFS_VECTOR  38    /* 16bit */
  55 #define OFFS_IP      40    /* 16bit */
  56 #define OFFS_CS      42    /* 16bit */
  57 #define OFFS_FLAGS   44    /* 16bit */
  58
  59 #define SEGMENT      0x40
  60 #define STACK        0x800      /* stack at 0x40:0x800 -> 0x800 */
  61
  62 /* save general registers */
  63 /* save some segments     */
  64 /* save callers stack segment .. */
  65 /* ... in gs */
  66         /* setup my segments */
  67         /* setup BIOS stackpointer */
  68
  69 #define MAKE_BIOS_STACK \
  70         pushal; \
  71         pushw   %ds; \
  72         pushw   %gs; \
  73         pushw   %es; \
  74         pushw   %ss; \
  75         popw    %gs; \
  76         movw    $SEGMENT, %ax; \
  77         movw    %ax, %ds; \
  78         movw    %ax, %es; \
  79         movw    %ax, %ss; \
  80         movw    %sp, %bp; \
  81         movw    $STACK, %sp
  82
  83 #define RESTORE_CALLERS_STACK \
  84         pushw   %gs;            /* restore callers stack segment */ \
  85         popw    %ss; \
  86         movw    %bp, %sp;       /* restore stackpointer */ \
  87         popw    %es;            /* restore segment selectors */ \
  88         popw    %gs; \
  89         popw    %ds; \
  90         popal                   /* restore GP registers */
  91
  92 #endif