138 lines
2.1 KiB
NASM
138 lines
2.1 KiB
NASM
; Print AL
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space: mov al, ' '
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putc: push bx
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xor bx, bx
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mov ah, 0x0e
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int 0x10
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pop bx
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ret
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; Print code string CS:SI
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putcs: push ds
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push cs
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pop ds
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call putds
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pop ds
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ret
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; Print data string DS:SI
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putds: lodsb
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test al, al
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jz .ret
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call putc
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jmp putds
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.ret: ret
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crlf: mov al, 0x0A
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call putc
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mov al, 0x0D
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jmp putc
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print16:
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mov cl, 4
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; this double-call is essentially a 4 times repeating loop
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call .c1
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.c1: call .c2
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.c2: ; grab highest nibble from dx
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mov al, dh
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; remove highest nibble from dx
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shl dx, cl
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; shift away second-highest nibble that we accidentally copied
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shr al, cl
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; map 0-9 to ascii codes for '0' to '9'
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add al, 0x30
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; if result is larger than '9', ...
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cmp al, 0x3a
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jl putc
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; ... add 7 so we continue at 'A'
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add al, 7
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jmp putc
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; Read character
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getc: xor ax, ax
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int 0x16
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test al, al
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jz getc
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test al, 0x80
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jnz getc
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ret
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; Read uppercased character
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getcu: call getc
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cmp al, 'a'
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jc .ret
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cmp al, 'z'
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ja .ret
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and al, 0xDF
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.ret: ret
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; Read hexadecimal character
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getch: call getcu
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; everything above F is invalid
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cmp al, 'F'
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ja getch
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; everything above or equal A is ok
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cmp al, 'A'
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jae .ret
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; everything above 9 is invalid
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cmp al, '9'
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ja getc
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; everything above or equal 0 is valid
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cmp al, '0'
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jae .ret
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; everything above or equal ' ' is invalid
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cmp al, ' '
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jae getch
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.ret: ret
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; Read string into inbuf
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; IN ingetc ptr to getc function
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; inlen max number of chars
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gets: push bx
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mov di, inbuf
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; calculate max pointer for writing
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mov dx, [inmin]
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.loop: call [ingetc]
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; test for Ctrl+C, Enter and Backspace
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cmp al, 0x03
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je .can
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cmp al, 0x0D
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je .enter
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cmp al, 0x08
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je .bs
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; ignore other ctl chars
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cmp al, 0x20
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jc .loop
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; check if we are full
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mov bx, di
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sub bx, inbuf
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; bl is now number of characters we have
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cmp bl, dh
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jnc .loop
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stosb
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call putc
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jmp .loop
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; backspace: print, print space, print backspace again
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.bs: cmp di, inbuf
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jbe .loop
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push ax
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call putc
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call space
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pop ax
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call putc
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dec di
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jmp .loop
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; ctrl+c: return with carry set
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.can: stc
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pop bx
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ret
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; enter: if enough chars, return
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.enter: mov bx, di
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sub bx, inbuf
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cmp bl, dl
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jc .loop
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xor al, al
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stosb
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pop bx
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ret
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