106 lines
2.4 KiB
ArmAsm
106 lines
2.4 KiB
ArmAsm
BITS 16
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;; Steps for building
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;; nasm -o stage1_disk_copier stage1_disk_copier.s
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;;
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;; Steps for testing
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;; qemu -fda stage0
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;; manually toggle in program hex
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;; or
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;; qemu -fda stage1_loader -fdb output
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;; then change floppy0 to the compiled version of this file
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start:
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mov sp, 256 ; Allocate 256B for stack
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mov ax, 7e00h ; Which is much more than we need
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mov ss, ax ; And stopping before this code
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;; Prompt user to press any key after loading desire source into A:
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mov ax, MSG0
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call print_string
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;; Wait until the user presses a key
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call read_key
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;; Inform the user that we are starting to read
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mov ax, MSG1
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call print_string
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;; Read A: into memory
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call read_floppy
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;; Inform the user that we completed reading A: and are starting to write B:
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mov ax, MSG2
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call print_string
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;; Start writing memory into B:
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call write_floppy2
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;; Inform the user that we completed writing to B:
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mov ax, MSG3
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call print_string
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jmp start
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;; Our glourious strings
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MSG0 db 'Load source into A: and hit any key',10,13,0
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MSG1 db 'Starting to read A:',10,13,0
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MSG2 db 'Read Complete, Starting to write B:',10,13,0
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MSG3 db 'Write Complete',10,13, 0
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;; Deal with the problem of printing the above strings
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print_string:
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push bx
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mov bx, ax
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.L0:
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mov al, [cs:bx]
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cmp al, 0
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je .L99
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call print_char
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add bx, 1
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jmp .L0
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.L99:
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pop bx
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ret
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print_char:
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; Routine: output char in al to screen
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mov ah, 0Eh ; int 10h 'print char' function
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int 10h ; print it
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ret
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read_floppy:
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;; Read bytes from floppy
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push 02000h ; Use The read space
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pop es ; ES is needed to be set for bios call
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mov al, 128 ; Read 2^15 Bytes from diskette
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mov ah, 02h ; Read Sectors to Memory
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mov ch, 0 ; Cylinder Number
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mov cl, 1 ; Starting sector number
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mov dh, 0 ; Drive head number
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mov dl, 00h ; Drive number [first floppy]
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mov bx, 0h ; Starting address
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int 13h ; Make the function call
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jc read_floppy
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ret
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read_key:
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;; Routine: read a char into al
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mov ah, 00h
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int 16h
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ret
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write_floppy2:
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;; Write bytes onto floppy2
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push 02000h ; Use the read space
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pop es ; ES is needed to be set for bios all
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mov al, 128 ; Write 2^15 Bytes to diskette
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mov ah, 03h ; Write Sectors from Memory
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mov ch, 0 ; Cylinder Number
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mov cl, 1 ; Starting sector number
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mov dh, 0 ; Drive head number
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mov dl, 01h ; Drive number [second floppy]
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mov bx, 0h ; Starting address
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int 13h ; Make the function call
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jc write_floppy2
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ret
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