a2bejwld/a2bejwld/vbl.s

;
;  vbl.s
;  a2bejwld
;
;  Created by Jeremy Rand on 2016-07-22.
;  Copyright © 2016 Jeremy Rand. All rights reserved.
;


    .export _vblWait, _vblWait2c, _vblInit2gs
    .export _vblIRQCallback


    .include "apple2.inc"


RDVBLBAR      :=  $C019


.proc _vblInit2gs
    lda #$fe
    sta compType
.endproc


.proc _vblWait
    lda   compType
@L1:
    cmp   RDVBLBAR
    bpl   @L1
@L2:
    cmp   RDVBLBAR
    bmi   @L2

    rts
.endproc


.proc _vblIRQCallback
    pha
    lda #0
    sta vbl2cByte
    pla
    rts
.endproc


.proc _vblWait2c
    lda #$ff
    sta vbl2cByte

@L1:
    lda vbl2cByte
    bne @L1

    rts
.endproc


.data

compType:
    .BYTE   $7e

vbl2cByte:
    .BYTE   $00
Add star animations. 2016-07-22 15:43:18 +00:00			`;`
			`; vbl.s`
			`; a2bejwld`
			`;`
			`; Created by Jeremy Rand on 2016-07-22.`
			`; Copyright © 2016 Jeremy Rand. All rights reserved.`
			`;`



			`.export _vblWait, _vblWait2c, _vblInit2gs`
Disable interrupts while reading from the joystick. By doing this, we can have the mouse and joystick drivers both enabled at the same time. Do not disable the mouse driver when mouse input is disabled. Register a "show" callback with the mouse driver and use that as a way to be notified of a VBL interval on the //c. 2016-09-07 02:55:05 +00:00			`.export _vblIRQCallback`
Add star animations. 2016-07-22 15:43:18 +00:00

			`.include "apple2.inc"`


			`RDVBLBAR := $C019`


			`.proc _vblInit2gs`
			`lda #$fe`
			`sta compType`
			`.endproc`


			`.proc _vblWait`
			`lda compType`
			`@L1:`
			`cmp RDVBLBAR`
			`bpl @L1`
			`@L2:`
			`cmp RDVBLBAR`
			`bmi @L2`

			`rts`
			`.endproc`


Disable interrupts while reading from the joystick. By doing this, we can have the mouse and joystick drivers both enabled at the same time. Do not disable the mouse driver when mouse input is disabled. Register a "show" callback with the mouse driver and use that as a way to be notified of a VBL interval on the //c. 2016-09-07 02:55:05 +00:00			`.proc _vblIRQCallback`
Make the project clean of 65c02 instructions. This should let this run on an unenhanced //e. 2020-01-23 04:31:42 +00:00			`pha`
			`lda #0`
			`sta vbl2cByte`
			`pla`
Disable interrupts while reading from the joystick. By doing this, we can have the mouse and joystick drivers both enabled at the same time. Do not disable the mouse driver when mouse input is disabled. Register a "show" callback with the mouse driver and use that as a way to be notified of a VBL interval on the //c. 2016-09-07 02:55:05 +00:00			`rts`
			`.endproc`


Add star animations. 2016-07-22 15:43:18 +00:00			`.proc _vblWait2c`
Disable interrupts while reading from the joystick. By doing this, we can have the mouse and joystick drivers both enabled at the same time. Do not disable the mouse driver when mouse input is disabled. Register a "show" callback with the mouse driver and use that as a way to be notified of a VBL interval on the //c. 2016-09-07 02:55:05 +00:00			`lda #$ff`
			`sta vbl2cByte`

			`@L1:`
			`lda vbl2cByte`
			`bne @L1`

Add star animations. 2016-07-22 15:43:18 +00:00			`rts`
			`.endproc`


			`.data`

			`compType:`
Disable interrupts while reading from the joystick. By doing this, we can have the mouse and joystick drivers both enabled at the same time. Do not disable the mouse driver when mouse input is disabled. Register a "show" callback with the mouse driver and use that as a way to be notified of a VBL interval on the //c. 2016-09-07 02:55:05 +00:00			`.BYTE $7e`

			`vbl2cByte:`
Make the project clean of 65c02 instructions. This should let this run on an unenhanced //e. 2020-01-23 04:31:42 +00:00			`.BYTE $00`