67 lines
832 B
NASM
67 lines
832 B
NASM
SECTION .text
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USE16
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; provide function for printing in x86 real mode
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; a newline
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newline: db 0xD, 0xA, 0
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; print a string and a newline
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; IN
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; si: points at zero-terminated String
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; CLOBBER
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; ax
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print_line:
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mov si, newline
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call print
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ret
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; print a string
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; IN
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; si: points at zero-terminated String
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; CLOBBER
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; ax
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print:
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lodsb
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test al, al
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jz .done
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call print_char
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jmp print
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.done:
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ret
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; print a character
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; IN
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; al: character to print
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; CLOBBER
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; ah
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print_char:
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mov ah, 0x0e
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int 0x10
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ret
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; print a number in hex
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; IN
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; bx: the number
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; CLOBBER
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; cx, ax
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print_num:
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mov cx, 4
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.lp:
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mov al, bh
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shr al, 4
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cmp al, 0xA
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jb .below_0xA
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add al, 'A' - 0xA - '0'
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.below_0xA:
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add al, '0'
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call print_char
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shl bx, 4
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loop .lp
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ret
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