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/* * 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 |