Created
September 30, 2018 10:16
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GNU assembly bootloader
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| .code16 | |
| .global _start | |
| _start: | |
| cli | |
| xor %ax, %ax | |
| mov %ax, %ds | |
| mov $msg, %si | |
| cld | |
| loop: | |
| lodsb | |
| or %al, %al | |
| jz hang | |
| mov $0x0E, %ah | |
| mov $0x00, %bh | |
| int $0x10 | |
| jmp loop | |
| hang: | |
| jmp hang | |
| msg: | |
| .string "BOOTLOADER" | |
| .byte 0x0D, 0x0A, 0x00 | |
| .org 510 | |
| .byte 0x55 | |
| .byte 0xAA |
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| #!/bin/bash | |
| set -ex | |
| rm -f boot.o boot.elf boot.bin | |
| i686-elf-as -o boot.o boot.S | |
| i686-elf-ld -Ttext 0x7C00 -o boot.elf boot.o | |
| objcopy -O binary boot.elf boot.bin |
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we do cli, should we be enabling interrupts later using sti