69 lines
952 B
NASM
69 lines
952 B
NASM
INCLUDE 'const.inc'
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INCLUDE 'multiboot.inc'
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ORG STAGE1_BASE
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USE32
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jmp _start
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ALIGN 4
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multiboot_header:
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mb_header MultibootHeader multiboot_header
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_start:
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cmp eax, MULTIBOOT_MAGIC
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je .multiboot
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USE16
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;; non multiboot process
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push cs
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pop ds
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mov si, msg_stage2
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call bios_print
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call a20_enable
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jc .error_a20
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; detect memory
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call memory_get_map
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jc .error_memory
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xchg bx, bx
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call video_setup
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.multiboot:
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jmp .hang
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.error_memory:
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mov si, msg_error_memory
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jmp .error
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.error_a20:
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mov si, msg_error_a20
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.error:
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call bios_print
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.hang:
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hlt
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jmp $
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INCLUDE 'a20.inc'
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INCLUDE 'utils.inc'
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INCLUDE 'memory.inc'
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INCLUDE 'video.inc'
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msg_stage2 db "StupidOS Bootloader (Stage 1)", CR, LF, 0
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msg_error_a20 db "ERROR: can't enable a20 line", CR, LF, 0
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msg_error_memory db "ERROR: can't detect available memory", CR, LF, 0
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;;
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bi_screen_width: dw 0
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bi_screen_height: dw 0
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_edata:
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; BSS
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rb 0x4000
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_end:
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