1 /* boot.S - bootstrap the kernel */ 2 /* Copyright (C) 1999, 2001 Free Software Foundation, Inc. 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 2 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, write to the Free Software 16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ 17 18 #define ASM 1 19 #include <multiboot.h> 20 21 .text 22 23 .globl start, _start 24 start: 25 _start: 26 jmp multiboot_entry 27 28 /* Align 32 bits boundary. */ 29 .align 4 30 31 /* Multiboot header. */ 32 multiboot_header: 33 /* magic */ 34 .long MULTIBOOT_HEADER_MAGIC 35 /* flags */ 36 .long MULTIBOOT_HEADER_FLAGS 37 /* checksum */ 38 .long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS) 39 #ifndef __ELF__ 40 /* header_addr */ 41 .long multiboot_header 42 /* load_addr */ 43 .long _start 44 /* load_end_addr */ 45 .long _edata 46 /* bss_end_addr */ 47 .long _end 48 /* entry_addr */ 49 .long multiboot_entry 50 #endif /* ! __ELF__ */ 51 52 multiboot_entry: 53 /* Initialize the stack pointer. */ 54 movl $(stack + STACK_SIZE), %esp 55 56 /* Reset EFLAGS. */ 57 pushl $0 58 popf 59 60 /* Push the pointer to the Multiboot information structure. */ 61 pushl %ebx 62 /* Push the magic value. */ 63 pushl %eax 64 65 /* Now enter the C main function... */ 66 call EXT_C(cmain) 67 68 /* Halt. */ 69 pushl $halt_message 70 call EXT_C(printf) 71 72 loop: hlt 73 jmp loop 74 75 halt_message: 76 .asciz "Halted." 77 78 /* Our stack area. */ 79 .comm stack, STACK_SIZE 80
