Input - Revision history

Trixter: /* Reading the Mouse */

2016-08-14T20:16:23Z

‎Reading the Mouse

Trixter: /* Reading the Mouse */

2016-08-14T20:16:09Z

‎Reading the Mouse

HellMood: adding mouse interaction and "point" snippet

2016-08-14T14:33:44Z

adding mouse interaction and "point" snippet

HellMood: DOS alternative, Int 16/AH=01h

2016-08-14T14:21:44Z

DOS alternative, Int 16/AH=01h

HellMood: /* Checking for ESCAPE */

2016-08-14T14:14:45Z

‎Checking for ESCAPE

Trixter at 06:57, 7 August 2016

2016-08-07T06:57:39Z

Trixter: Created page with "== Checking for ESCAPE == This is fairly easy: Monitor the keyboard scancode port for ESC which is #1, then deal with it: in al,60h..."

2016-08-07T06:26:57Z

Created page with "== Checking for ESCAPE == This is fairly easy: Monitor the keyboard scancode port for ESC which is #1, then deal with it: <syntaxhighlight lang=nasm> in al,60h..."

New page

== Checking for ESCAPE ==

This is fairly easy: Monitor the keyboard scancode port for ESC which is #1, then deal with it:

<syntaxhighlight lang=nasm>
in al,60h ;read whatever is at keyboard port; looking for ESC which is #1
dec ax ;if ESC, AX now 0
jnz mainloop ;fall through if 0, do jump somewhere else if otherwise
</syntaxhighlight>

← Older revision		Revision as of 20:16, 14 August 2016
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	* [http://www.ctyme.com/intr/int-33.htm general overview]		* [http://www.ctyme.com/intr/int-33.htm general overview]

−	For a case study, [[Paint16b\|a little "Paint" implementation]] is possible in 16 bytes.	+	For a case study in putting this together in a tinyprog, [[Paint16b\|a little "Paint" implementation]] is possible in 16 bytes.

← Older revision		Revision as of 20:16, 14 August 2016
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	* [http://www.ctyme.com/intr/int-33.htm general overview]		* [http://www.ctyme.com/intr/int-33.htm general overview]

−	~~It appears that~~ a little "Paint" implementation is ~~[http://www.pouet.net/prod.php?which=63826~~ possible in 16 bytes]	+	For a case study, [[Paint16b\|a little "Paint" implementation]] is possible in 16 bytes.
−	~~<syntaxhighlight lang=nasm>~~
−	~~org 100h ; code starts at 0x100~~
−	~~mov al,0x12 ; assume ah = 0 ; set graphics mode to 640*480~~
−	~~inc bx ; assume bx = 0 ; set to 1 (show cursor)~~
−	~~mloop:~~
−	~~int 0x10 ; first loop, switch to graphic mode~~
−	~~; further loops, set pixel~~
−	~~xchg bx,ax ; first loop, set AX to 1 (show cursor)~~
−	~~; further loops, restore old calling mode~~
−	~~xor al,0x02 ; switch modes : show cursor <-> get mouse state~~
−	~~; updating XY every second loop plus drawing~~
−	~~; one pixel left results in thicker lines~~
−	~~int 0x33 ; call the mouse interrupt~~
−	~~xchg bx,ax ; store the button state in AL for drawing~~
−	~~; remember the current calling mode~~
−	~~; for switching it later (in BX)~~
−	~~mov ah,0x0C ; set mode to "set pixel"~~
−	~~loop mloop ; dec CX -> draw one pixel left from cursor~~
−	~~; basically enables drawing pixels~~
−	~~; while the cursor is active~~
−	~~; allows exit if the mouse is leftmost~~
−	~~ret ; assume [[FFEE]] = [0] = CD20 = int 20~~
−	~~</syntaxhighlight>~~

← Older revision		Revision as of 14:33, 14 August 2016
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	See also : [http://www.ctyme.com/intr/rb-1755.htm Ralf Browns Interrupt List : Int 16/AH=01h]		See also : [http://www.ctyme.com/intr/rb-1755.htm Ralf Browns Interrupt List : Int 16/AH=01h]
		+
		+	== Reading the Mouse ==
		+
		+	For more sophisticated interaction with the mouse, there is <code>int 33h</code>. The most important interactions :
		+
		+	* [http://www.ctyme.com/intr/rb-5957.htm show mouse cursor - Int 33/AX=0001h]
		+	* [http://www.ctyme.com/intr/rb-5959.htm return position and button status - Int 33/AX=0003h]
		+	* [http://www.ctyme.com/intr/int-33.htm general overview]
		+
		+	It appears that a little "Paint" implementation is [http://www.pouet.net/prod.php?which=63826 possible in 16 bytes]
		+	<syntaxhighlight lang=nasm>
		+	org 100h ; code starts at 0x100
		+	mov al,0x12 ; assume ah = 0 ; set graphics mode to 640*480
		+	inc bx ; assume bx = 0 ; set to 1 (show cursor)
		+	mloop:
		+	int 0x10 ; first loop, switch to graphic mode
		+	; further loops, set pixel
		+	xchg bx,ax ; first loop, set AX to 1 (show cursor)
		+	; further loops, restore old calling mode
		+	xor al,0x02 ; switch modes : show cursor <-> get mouse state
		+	; updating XY every second loop plus drawing
		+	; one pixel left results in thicker lines
		+	int 0x33 ; call the mouse interrupt
		+	xchg bx,ax ; store the button state in AL for drawing
		+	; remember the current calling mode
		+	; for switching it later (in BX)
		+	mov ah,0x0C ; set mode to "set pixel"
		+	loop mloop ; dec CX -> draw one pixel left from cursor
		+	; basically enables drawing pixels
		+	; while the cursor is active
		+	; allows exit if the mouse is leftmost
		+	ret ; assume [[FFEE]] = [0] = CD20 = int 20
		+	</syntaxhighlight>

← Older revision		Revision as of 14:21, 14 August 2016
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	The above are somewhat flaky due to different hardware, VMs, and emulators not honoring flags correctly.		The above are somewhat flaky due to different hardware, VMs, and emulators not honoring flags correctly.
		+
		+	== The DOS alternative ==
		+
		+	In very small productions, it's sometimes impossible to use one of the above, since <code>AL</code> contains intermediate results or pixel values all the time. Luckily there is <code>int 16h</code> which checks for any key with the following code :
		+
		+	<syntaxhighlight lang=nasm>
		+	mov ah,1 ; subfunction AH = 1, check for key
		+	int 16h
		+	jz mainloop ; ZF set if no keystroke available
		+	</syntaxhighlight>
		+
		+	See also : [http://www.ctyme.com/intr/rb-1755.htm Ralf Browns Interrupt List : Int 16/AH=01h]

← Older revision		Revision as of 06:57, 7 August 2016
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	jnz mainloop ;fall through if 0, do jump somewhere else if otherwise		jnz mainloop ;fall through if 0, do jump somewhere else if otherwise
	</syntaxhighlight>		</syntaxhighlight>
		+
		+	== Checking for '''any''' keypress ==
		+
		+	If you need to shave a byte, it might be possible in some environments to check for any keypress instead of just escape using less code:
		+
		+	<syntaxhighlight lang=nasm>
		+	in al,60h ;read whatever is at keyboard port
		+	das ;If non-zero, parity will be set
		+	jp mainloop ;Jump if parity
		+	</syntaxhighlight>
		+
		+	An alternative if not running DOSBox:
		+
		+	<syntaxhighlight lang=nasm>
		+	in al,60h ;read whatever is at keyboard port
		+	aaa
		+	jz mainloop ;Jump if zero
		+	</syntaxhighlight>
		+
		+	The above are somewhat flaky due to different hardware, VMs, and emulators not honoring flags correctly.

@@ Line 8: / Line 8: @@
          jnz     mainloop        ;fall through if 0, do jump somewhere else if otherwise
 </syntaxhighlight>
 == Checking for '''any''' keypress ==