173 lines
2.2 KiB
PHP
173 lines
2.2 KiB
PHP
;Reads a string of at most al characters to di until a return and prints a newline.
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readln:
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;Store the length
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mov [.length], al
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;Initialise the destination with spaces
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mov cx, [.length]
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mov al, 0x20
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rep stosb
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sub di, [.length]
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;Initialise the cursor pointer
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mov bl, 0x1
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;Initialise the last input line pointer
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mov ah, 0x3
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int 0x10
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mov byte [.lastln], dh
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.loop:
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;Read a keypress
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mov ah, 0x0
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int 0x16
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;Check for null
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cmp al, 0x0
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je .loop
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;Check for return
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cmp al, 0xd
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je .return
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;Check for backspace
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cmp al, 0x8
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je .backspace
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;Check for input end
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cmp bl, [.length]
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je .loop
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;Check for space
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cmp al, 0x20
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je .space
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;Check for erase
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cmp al, 0x9
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je .erase
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;Check for non-printing characters
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cmp al, 0x1f
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jle .loop
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cmp al, 0x7f
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je .loop
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.char:
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;Store the character
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stosb
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;Print the character
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mov ah, 0xe
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int 0x10
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;Move the cursor pointer
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inc bl
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.checkln:
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;Get the cursor position
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mov ah, 0x3
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int 0x10
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;Check if the current line is the last one of the input
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cmp dh, [.lastln]
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jle .loop
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;If it is mark it as so
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mov byte [.lastln], dh
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jmp .loop
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.erase:
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;Replace the cursor position with a space
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mov al, 0x20
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jmp .char
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.space:
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;Get the cursor position
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mov ah, 0x3
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int 0x10
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;More from the end of a line to the beginning of the next one
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cmp dl, [cpl]
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je .nextln
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;Move forward within a line
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inc dl
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mov ah, 0x2
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int 0x10
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inc di
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inc bl
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jmp .loop
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.nextln:
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mov ah, 0x2
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inc dh
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mov dl, 0x1
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int 0x10
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inc di
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inc bl
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;Go to the last input line check
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jmp .checkln
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.backspace:
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;Check for the input beginning
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cmp bl, 0x0
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je .loop
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;Get the cursor position
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mov ah, 0x3
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int 0x10
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;More from the beginning of a line to the end of the previous one
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cmp dl, 0x1
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je .prevln
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;Move backward within a line
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dec dl
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mov ah, 0x2
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int 0x10
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dec di
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dec bl
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jmp .loop
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.prevln:
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mov ah, 0x2
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dec dh
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mov dl, [cpl]
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int 0x10
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dec di
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dec bl
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jmp .loop
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.return:
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;Go to the end of the input
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mov bh, 0x0
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sub di, bx
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add di, [.length]
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.findtrailing:
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;Check for a trailing space
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cmp byte [di], 0x20
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je .deltrailing
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jmp .done
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.deltrailing:
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;Delete a trailing space
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mov al, 0x0
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stosb
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sub di, 0x2
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jmp .findtrailing
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.done:
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;Move the cursor to the last line of input
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mov ah, 0x2
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mov dh, [.lastln]
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int 0x10
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;Print a newline
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call newline
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ret
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.length:
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db 0x0
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.cursor:
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db 0x0
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.lastln:
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db 0x0
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