1 /* 2 * GRUB -- GRand Unified Bootloader 3 * Copyright (C) 2000, 2001 Free Software Foundation, Inc. 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 /* This is stolen from arch/i386/boot/setup.S in Linux 2.2.17 */ 21 /* 22 ! setup.S Copyright (C) 1991, 1992 Linus Torvalds 23 */ 24 25 ENTRY(get_apm_info) 26 pushl %ebp 27 pushl %ebx 28 pushl %edi 29 pushl %esi 30 31 call EXT_C(prot_to_real) 32 .code16 33 34 /* APM BIOS installation check */ 35 movw $0x5300, %ax 36 xorw %bx, %bx 37 int $0x15 38 /* error -> no APM BIOS */ 39 jc done_apm_bios 40 41 /* check for "PM" signature */ 42 cmpw $0x504d, %bx 43 /* no signature -> no APM BIOS */ 44 jne done_apm_bios 45 46 /* Is 32 bit supported? */ 47 andw $0x0002, %cx 48 /* no ... */ 49 je done_apm_bios 50 51 /* Disconnect first just in case */ 52 movw $0x5304, %ax 53 xorw %bx, %bx 54 /* ignore return code */ 55 int $0x15 56 57 /* 32 bit connect */ 58 movw $0x5303, %ax 59 xorl %ebx, %ebx 60 /* paranoia */ 61 xorw %cx, %cx 62 xorw %dx, %dx 63 xorl %esi, %esi 64 xorw %di, %di 65 int $0x15 66 /* error */ 67 jc no_32_apm_bios 68 69 /* BIOS code segment */ 70 movw %ax, ABS(EXT_C(apm_bios_info)) + 2 71 /* BIOS entry point offset */ 72 movl %ebx, ABS(EXT_C(apm_bios_info)) + 4 73 /* BIOS 16 bit code segment */ 74 movw %cx, ABS(EXT_C(apm_bios_info)) + 8 75 /* BIOS data segment */ 76 movw %dx, ABS(EXT_C(apm_bios_info)) + 10 77 /* BIOS code segment length */ 78 movl %esi, ABS(EXT_C(apm_bios_info)) + 14 79 /* BIOS data segment length */ 80 movw %di, ABS(EXT_C(apm_bios_info)) + 18 81 82 /* 83 * Redo the installation check as the 32 bit connect 84 * modifies the flags returned on some BIOSs 85 */ 86 87 /* APM BIOS installation check */ 88 movw $0x5300, %ax 89 xorw %bx, %bx 90 /* paranoia */ 91 xorw %cx, %cx 92 int $0x15 93 /* error -> should not happen, tidy up */ 94 jc done_apm_bios 95 96 /* check for "PM" signature */ 97 cmpw $0x504d, %bx 98 /* no signature -> should not happen, tidy up */ 99 jne done_apm_bios 100 101 /* record the APM BIOS version */ 102 movw %ax, ABS(EXT_C(apm_bios_info)) 103 /* and flags */ 104 movw %cx, ABS(EXT_C(apm_bios_info)) + 12 105 jmp done_apm_bios 106 107 no_32_apm_bios: 108 /* remove 32 bit support bit */ 109 andw $0xfffd, ABS(EXT_C(apm_bios_info)) + 12 110 111 done_apm_bios: 112 /* Some paranoia here: Always Disconnect from APM */ 113 movw $0x5304, %ax 114 xorw %bx, %bx 115 /* ignore return code */ 116 int $0x15 117 118 DATA32 call EXT_C(real_to_prot) 119 .code32 120 121 popl %esi 122 popl %edi 123 popl %ebx 124 popl %ebp 125 ret 126
