reactos/boot/freeldr/freeldr/arch/i386/i386pnp.S

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 2003  Eric Kohl  <ekohl@rz-online.de>
   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
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20         .text
  21         .code16
  22
  23 #define ASM
  24
  25 #include <arch.h>
  26
  27
  28 /*
  29  * U32 PnpBiosSupported(VOID);
  30  *
  31  * RETURNS:
  32  */
  33 _pnp_bios_entry_point:
  34         .long   0
  35 _pnp_bios_data_segment:
  36         .word   0
  37
  38 EXTERN(_PnpBiosSupported)
  39         .code32
  40
  41         pushl   %edi
  42         pushl   %esi
  43         pushl   %ecx
  44         pushl   %edx
  45
  46         xorl    %edi,%edi
  47
  48         /* init esi */
  49         movl    $0xF0000,%esi
  50
  51 pnp_again:
  52         movl    (%esi),%eax
  53         cmp             $0x506E5024,%eax                        /* "$PnP" */
  54         je              pnp_found
  55
  56         cmp             $0xFFFF0,%esi
  57         je              pnp_not_found
  58
  59 pnp_add:
  60         addl    $0x10,%esi
  61         jmp             pnp_again
  62
  63 pnp_found:
  64         /* first calculate the checksum */
  65         pushl   %esi
  66
  67         pushl   $0x21
  68         popl    %ecx
  69         xorl    %edx, %edx
  70
  71 pnp_loop:
  72         lodsb
  73         addb    %al,%dl
  74         loopl   pnp_loop
  75
  76         testb   %dl, %dl
  77         popl    %esi
  78         jnz             pnp_add
  79
  80         movl    %esi,%edi
  81
  82         /* Calculate the bios entry point (far pointer) */
  83         xorl    %eax,%eax
  84         movw    0x0F(%esi),%ax
  85         shll    $16,%eax
  86         movw    0x0D(%esi),%ax
  87         movl    %eax,_pnp_bios_entry_point
  88
  89         /* Store bios data segment */
  90         movw    0x1B(%esi),%ax
  91         movw    %ax,_pnp_bios_data_segment
  92
  93 pnp_not_found:
  94         movl    %edi,%eax
  95
  96         popl    %edx
  97         popl    %ecx
  98         popl    %esi
  99         popl    %edi
 100
 101         ret
 102
 103
 104 /*
 105  * U32 PnpBiosGetDeviceNodeCount(U32 *NodeSize, U32 *NodeCount);
 106  *
 107  * RETURNS:
 108  */
 109 _pnp_result:
 110         .long   0
 111 _pnp_node_size:
 112         .word   0
 113 _pnp_node_count:
 114         .word   0
 115
 116 EXTERN(_PnpBiosGetDeviceNodeCount)
 117         .code32
 118
 119         pushl   %ebp
 120         movl    %esp,%ebp
 121
 122         pushal
 123         push    %es
 124
 125         call    switch_to_real
 126         .code16
 127
 128         movw    _pnp_bios_data_segment,%ax
 129         pushw   %ax
 130
 131         pushw   %cs
 132         movw    $(_pnp_node_size),%ax
 133         pushw   %ax
 134
 135         pushw   %cs
 136         movw    $(_pnp_node_count),%ax
 137         pushw   %ax
 138
 139         pushw   $0
 140
 141         lcall   *_pnp_bios_entry_point
 142         addw    $12,%sp
 143
 144         movzwl  %ax,%ecx
 145         movl    %ecx,_pnp_result
 146
 147
 148         call    switch_to_prot
 149         .code32
 150
 151         movl    0x08(%ebp),%esi
 152         movw    _pnp_node_size,%ax
 153         movzwl  %ax,%ecx
 154         movl    %ecx, (%esi)
 155
 156         movl    0x0C(%ebp),%esi
 157         movw    _pnp_node_count,%ax
 158         movzwl  %ax,%ecx
 159         movl    %eax, (%esi)
 160
 161         pop             %es
 162         popal
 163
 164         movl    %ebp,%esp
 165         popl    %ebp
 166
 167         movl    _pnp_result,%eax
 168
 169         ret
 170
 171
 172 /*
 173  * U32 PnpBiosGetDeviceNode(U8 *NodeId, U8 *NodeBuffer);
 174  *
 175  * RETURNS:
 176  */
 177 _pnp_buffer_segment:
 178         .word   0
 179 _pnp_buffer_offset:
 180         .word   0
 181
 182 _pnp_node_number:
 183         .byte   0
 184
 185 EXTERN(_PnpBiosGetDeviceNode)
 186         .code32
 187
 188         pushl   %ebp
 189         movl    %esp,%ebp
 190
 191         pushal
 192         push    %es
 193
 194         /* get current node number */
 195         movl    0x08(%ebp),%esi
 196         movb    (%esi),%al
 197         movb    %al,_pnp_node_number
 198
 199         /* convert pointer to node buffer to segment/offset */
 200         movl    0x0C(%ebp),%eax
 201         shrl    $4,%eax
 202         andl    $0xf000,%eax
 203         movw    %ax,_pnp_buffer_segment
 204         movl    0x0C(%ebp),%eax
 205         andl    $0xffff,%eax
 206         movw    %ax,_pnp_buffer_offset
 207
 208         call    switch_to_real
 209         .code16
 210
 211         /* push bios segment */
 212         movw    _pnp_bios_data_segment,%ax
 213         pushw   %ax
 214
 215         /* push control flag */
 216         pushw   $0x0001
 217
 218         /* push pointer to node buffer (segment/offset) */
 219         movw    _pnp_buffer_segment,%ax
 220         pushw   %ax
 221         movw    _pnp_buffer_offset,%ax
 222         pushw   %ax
 223
 224         /* push pointer to node number (segment/offset) */
 225         pushw   %cs
 226         movw    $(_pnp_node_number),%ax
 227         pushw   %ax
 228
 229         /* push function number */
 230         pushw   $1
 231
 232         /* call entry point */
 233         lcall   *_pnp_bios_entry_point
 234         addw    $14,%sp
 235
 236         movzwl  %ax,%ecx
 237         movl    %ecx,_pnp_result
 238
 239         call    switch_to_prot
 240         .code32
 241
 242         /* update node number */
 243         movl    0x08(%ebp),%esi
 244         movb    _pnp_node_number,%al
 245         movb    %al,(%esi)
 246
 247         pop             %es
 248         popal
 249
 250         movl    %ebp,%esp
 251         popl    %ebp
 252
 253         movl    _pnp_result,%eax
 254
 255         ret
 256
 257 /* EOF */