the10thwiz/cc65
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Workaround for "phantom" key presses in the C128 "joystick" mouse driver.

Browse Source
This commit is contained in:
Christian Groessler
2014-04-22 15:48:49 +02:00
parent d4c9b25b2f
commit 608dbc2cec
2 changed files with 148 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

79
libsrc/c128/mou/c128-joy.s
View File

@@ -11,6 +11,8 @@
.macpack generic
IRQInd = $2FD
; ------------------------------------------------------------------------
; Header. Includes jump table
@@ -25,6 +27,7 @@ HEADER:
; Library reference
libref:
.addr $0000
; Jump table
@@ -70,6 +73,15 @@ SCREEN_WIDTH = 320
FIRE = $10
.endenum
;----------------------------------------------------------------------------
; data segment
.data
chainIRQ:
.byte $4c ; JMP opcode
.word 0 ; pointer to ROM IRQ handler (will be set at runtime)
;----------------------------------------------------------------------------
; Global variables. The bounding box values are sorted so that they can be
; written with the least effort in the SETBOX and GETBOX routines, so don't
@@ -92,6 +104,10 @@ INIT_save: .res 1
Temp: .res 1
; Keyboard buffer fill level at start of interrupt
old_key_count: .res 1
.rodata
; Default values for above variables
@@ -146,6 +162,35 @@ INSTALL:
jsr CMOVEY
cli
; Initialize our IRQ magic
lda IRQInd+1
sta chainIRQ+1
lda IRQInd+2
sta chainIRQ+2
lda libref
sta ptr3
lda libref+1
sta ptr3+1
ldy #2
lda (ptr3),y
sta IRQInd+1
iny
lda (ptr3),y
sta IRQInd+2
iny
lda #<(callback-1)
sta (ptr3),y
iny
lda #>(callback-1)
sta (ptr3),y
iny
lda #<(chainIRQ-1)
sta (ptr3),y
iny
lda #>(chainIRQ-1)
sta (ptr3),y
; Done, return zero (= MOUSE_ERR_OK)
ldx #$00
@@ -157,6 +202,12 @@ INSTALL:
; No return code required (the driver is removed from memory on return).
UNINSTALL:
lda chainIRQ+1
sta IRQInd+1
lda chainIRQ+2
sta IRQInd+2
jsr HIDE ; Hide cursor on exit
lda INIT_save
sta INIT_STATUS
@@ -320,6 +371,8 @@ IOCTL: lda #<MOUSE_ERR_INV_IOCTL ; We don't support ioclts for now
;
IRQ: jsr CPREP
lda KEY_COUNT
sta old_key_count
lda #$7F
sta CIA1_PRA
lda CIA1_PRB ; Read joystick #0
@@ -436,3 +489,29 @@ IRQ: jsr CPREP
@SkipY: jsr CDRAW
clc ; Interrupt not "handled"
rts
;----------------------------------------------------------------------------
; Called after ROM IRQ handler has been run.
; Check if there was joystick activity before and/or after the ROM handler.
; If there was activity, discard the key presses since they are most
; probably "phantom" key presses.
callback:
ldx old_key_count
cpx KEY_COUNT
beq @nokey
lda Temp ; keypress before?
bne @discard_key ; yes, discard key
lda #$7F
sta CIA1_PRA
lda CIA1_PRB ; Read joystick #0
and #$1F
eor #$1F ; keypress after
beq @nokey ; no, probably a real key press
@discard_key:
stx KEY_COUNT ; set old keyboard buffer fill level
@nokey: rts