diff options
Diffstat (limited to 'arch/x86_64/boot/bootsect.S')
| -rw-r--r-- | arch/x86_64/boot/bootsect.S | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/arch/x86_64/boot/bootsect.S b/arch/x86_64/boot/bootsect.S new file mode 100644 index 00000000000..bb15d406ee9 --- /dev/null +++ b/arch/x86_64/boot/bootsect.S @@ -0,0 +1,98 @@ +/* + * bootsect.S Copyright (C) 1991, 1992 Linus Torvalds + * + * modified by Drew Eckhardt + * modified by Bruce Evans (bde) + * modified by Chris Noe (May 1999) (as86 -> gas) + * gutted by H. Peter Anvin (Jan 2003) + * + * BIG FAT NOTE: We're in real mode using 64k segments. Therefore segment + * addresses must be multiplied by 16 to obtain their respective linear + * addresses. To avoid confusion, linear addresses are written using leading + * hex while segment addresses are written as segment:offset. + * + */ + +#include <asm/boot.h> + +SETUPSECTS = 4 /* default nr of setup-sectors */ +BOOTSEG = 0x07C0 /* original address of boot-sector */ +INITSEG = DEF_INITSEG /* we move boot here - out of the way */ +SETUPSEG = DEF_SETUPSEG /* setup starts here */ +SYSSEG = DEF_SYSSEG /* system loaded at 0x10000 (65536) */ +SYSSIZE = DEF_SYSSIZE /* system size: # of 16-byte clicks */ + /* to be loaded */ +ROOT_DEV = 0 /* ROOT_DEV is now written by "build" */ +SWAP_DEV = 0 /* SWAP_DEV is now written by "build" */ + +#ifndef SVGA_MODE +#define SVGA_MODE ASK_VGA +#endif + +#ifndef RAMDISK +#define RAMDISK 0 +#endif + +#ifndef ROOT_RDONLY +#define ROOT_RDONLY 1 +#endif + +.code16 +.text + +.global _start +_start: + + # Normalize the start address + jmpl $BOOTSEG, $start2 + +start2: + movw %cs, %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %ss + movw $0x7c00, %sp + sti + cld + + movw $bugger_off_msg, %si + +msg_loop: + lodsb + andb %al, %al + jz die + movb $0xe, %ah + movw $7, %bx + int $0x10 + jmp msg_loop + +die: + # Allow the user to press a key, then reboot + xorw %ax, %ax + int $0x16 + int $0x19 + + # int 0x19 should never return. In case it does anyway, + # invoke the BIOS reset code... + ljmp $0xf000,$0xfff0 + + +bugger_off_msg: + .ascii "Direct booting from floppy is no longer supported.\r\n" + .ascii "Please use a boot loader program instead.\r\n" + .ascii "\n" + .ascii "Remove disk and press any key to reboot . . .\r\n" + .byte 0 + + + # Kernel attributes; used by setup + + .org 497 +setup_sects: .byte SETUPSECTS +root_flags: .word ROOT_RDONLY +syssize: .word SYSSIZE +swap_dev: .word SWAP_DEV +ram_size: .word RAMDISK +vid_mode: .word SVGA_MODE +root_dev: .word ROOT_DEV +boot_flag: .word 0xAA55 |