102 lines
1.3 KiB
NASM
102 lines
1.3 KiB
NASM
cpu 8086
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org 0x3000
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;Load a file and print it
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;Set the stack
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cli
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mov sp, stack + 0x100
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sti
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;Check for an empty tail
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;Check
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cmp byte [si], 0x0
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jne extract
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;Print an error message and abort if the tail is empty
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mov si, errormsg
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mov ah, 0x2
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int 0x21
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je done
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;Find the end of the filename and add a null if needed
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;Set DI at the tail
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extract:
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mov di, si
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findend:
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;Check for the string end
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cmp byte [di], 0x0
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je load
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;Check for a space
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cmp byte [di], 0x20
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je addnull
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inc di
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jmp findend
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;Add a null
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addnull:
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mov al, 0x0
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stosb
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;Load the file
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;Load
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load:
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mov bx, stack + 0x100
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mov ah, 0x2
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int 0x22
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;Check for errors
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cmp al, 0x0
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jne done
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;Print the file
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;Setup
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mov bh, 0x0
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mov bl, 0x18
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mov dl, 0x50
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mov si, stack + 0x100
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;Decrease the character counter
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print:
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dec dl
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;Load the current character
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lodsb
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;Print the character
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mov ah, 0xe
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int 0x10
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;Check for a hard line end
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cmp al, 0xa
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je linecount
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;Check for a soft line end
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cmp dl, 0x0
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je linecount
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;Check paging
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contprint:
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cmp bl, 0x0
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jz page
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;Repeat for the next character
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loop print
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jmp done
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;Decrease the line counter and reset the character one
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linecount:
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dec bl
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mov dl, 0x50
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jmp contprint
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;Page
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page:
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push ax
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mov ah, 0x0
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int 0x16
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cmp al, 0x1b
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je done
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pop ax
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mov bl, 0x18
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mov dl, 0x50
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loop print
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;Return to the system
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done:
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int 0x20
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;Data
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errormsg db "File not found", 0x0
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;Stack
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stack:
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