Code Snippets

LICENSE

Get input and output permission to a port

Open a File with read/write access

Get max priority for shedule in fifo (first in first out) mode

Change shedule mode to fifo

Get the terminal attributes

Set the terminal attributes

Read 1 byte from the standart input (keyboard)

;-- Get input and output permission to a port. --
; You must have root permission for execution

	mov	eax,101	;ioperm
	mov	ebx,$37A	;start port / parallelport
	mov	ecx,1	;1port long
	mov	edx,1	;allow
	int	$80
	cmp	eax,0
	jz	continue
	call	error	;your error procedure
	jmp	end
.continue:

;-- Open a File with read/write access --

	mov	eax,5	;open File
	mov	ebx,datname	;-> file name
	mov	ecx,2	;read/write
	int	$80
	cmp	eax,0
	jge	.continue
	call	error	;your error procedure
	jmp	end
.continue:

;-- Get max priority for shedule in fifo (first in first out) mode. --
;Useful with the next one.

	mov	eax,159	;SCHED_GET_PRIORITY_MAX
	mov	ebx,1	;policy FIFO
	int	$80
	cmp	eax,0	;priority
	jg	.continue
	call	error	;your error procedure
	jmp	end
.continue:

;-- Change shedule mode to fifo. --
;That's the only way under Linux to get ful realtime control of (port) outputs.
;Disatvantage: You can't use the Xterminal any more and such programms they use it,
;because all other tasks are stoped until you switch back to shed other mode f.e.
;So no mouse pointer is moveing and no key that's pressed is written to the display.
;So it is absolutly necessary to give the user a possibility to exit your program. See next.

	mov	eax,156	;SCHED_SETSCHEDULAR
	mov	ebx,0	;pid = root
	mov	ecx,1	;policy = SCHED_FIFO
	mov	edx,priority	;-> priority
	int	$80
	cmp	eax,0
	jz	.continue
	call	error	;your error procedure
	jmp	end
.continue:

;-- Get the terminal attributes. --
;Necessary to restore them later.

	mov	eax,54
	mov	ebx,0
	mov	ecx,0x5401	;get terminal attributes
	mov	edx,.buf1	; -> .buf1 resb 28
	int	$80h
	cmp	eax,0
	jz	.continue
	call	error	;your error procedure
	jmp	end
.continue:

;-- Set the terminal attributes. --
;Set and clear the right bits before:
;To make the terminal return after 1 key is pressed (noncanonical) do this like:
;Don't forget to restore the terminal attributes with this funktion.

			;buf2 is a copy of buf1.
	and	dword[.buf2+12],11111111111111111111111111110101b
	or	dword[.buf2+12],00000000000000000100000000000000b
	and	byte[.buf2+17],11011111b
	mov	eax,54
	mov	ebx,0
	mov	ecx,0x5402	;set terminal attributes
	mov	edx,.buf2	; -> .buf2   resb   28
	int	80h
	cmp	eax,0
	jz	.continue
	call	error	;your error procedure
	jmp	end
.continue:

;-- Read 1 byte from the standart input (keyboard). --

	mov	eax,3	;Syscall read
	mov	ebx,0	;file number
	mov	ecx,buf+1	;-> buf db
	mov	edx,1	;count bytes
	int	80h	;read 1 byte
	cmp	eax,1	;count bytes
	je	.continue
	call	error	;your error procedure
	jmp	end
.continue: