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cc65/libsrc/c64/mou/c64-joy.s
Oliver Schmidt 2c975d3642 Create static drivers directly from source files.
Up to now static drivers were created via co65 from dynamic drivers. However there was an issue with that approach:

The dynamic drivers are "o65 simple files" which obligates that they start with the 'code' segment. However dynamic drivers need to start with the module header - which is written to. For dynamic drivers this isn't more than a conceptual issue because they are always contain a 'data' segment and may therefore only be loaded into writable memory.

However when dynamic drivers are converted to static drivers using co65 then that issue becomes a real problem as then the 'code' segment may end up in non-writable memory - and thus writing to the module header fails.

Instead of changing the way dynamic drivers work I opted to rather make static driver creation totally independent from dynamic drivers. This allows to place the module header in the 'data' segment (see 'module.mac').
2014-06-04 23:50:18 +02:00

451 lines
13 KiB
ArmAsm

;
; Driver for a "joystick mouse".
;
; Ullrich von Bassewitz, 2004-03-29, 2009-09-26
; 2014-03-17, Greg King
;
; The driver prevents the keyboard from interfering by changing the
; keyboard's output port into an input port while the driver reads its
; controller device. That disables a wire that is left active by the
; Kernal. That wire is used by the STOP-key to break out of BASIC
; programs -- CC65 programs don't use that feature. The wire is shared
; by these keys: STOP, "Q", Commodore, Space, "2", CTRL, Left-Arrow, and
; "1". I listed them, in order, from bit 7 over to bit 0. The
; rightmost five keys can look like joystick switches.
;
; The driver prevents the mouse/joystick from interfering by "blinding"
; the keyboard scanner while any button/switch is active. It changes
; the input port into an output port, then stores all zero-bits in that
; port's latch. Reading from an output port sees the bitwise-AND of the
; latch and the input signals. Therefore, the scanner thinks that eight
; keys are being pushed at the same time. It doesn't know what to do
; about that condition; so, it does nothing. The driver lets the
; scanner see normally, again, when no buttons/switches are active.
;
.include "zeropage.inc"
.include "mouse-kernel.inc"
.include "c64.inc"
.macpack generic
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _c64_joy_mou
HEADER:
; Driver signature
.byte $6d, $6f, $75 ; "mou"
.byte MOUSE_API_VERSION ; Mouse driver API version number
; Library reference
.addr $0000
; Jump table
.addr INSTALL
.addr UNINSTALL
.addr HIDE
.addr SHOW
.addr SETBOX
.addr GETBOX
.addr MOVE
.addr BUTTONS
.addr POS
.addr INFO
.addr IOCTL
.addr IRQ
; Mouse driver flags
.byte MOUSE_FLAG_LATE_IRQ
; Callback table, set by the kernel before INSTALL is called
CHIDE: jmp $0000 ; Hide the cursor
CSHOW: jmp $0000 ; Show the cursor
CPREP: jmp $0000 ; Prepare to move the cursor
CDRAW: jmp $0000 ; Draw the cursor
CMOVEX: jmp $0000 ; Move the cursor to X coord
CMOVEY: jmp $0000 ; Move the cursor to Y coord
;----------------------------------------------------------------------------
; Constants
SCREEN_HEIGHT = 200
SCREEN_WIDTH = 320
.enum JOY
UP = $01
DOWN = $02
LEFT = $04
RIGHT = $08
FIRE = $10
.endenum
;----------------------------------------------------------------------------
; 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
; reorder them.
.bss
Vars:
YPos: .res 2 ; Current mouse position, Y
XPos: .res 2 ; Current mouse position, X
XMin: .res 2 ; X1 value of bounding box
YMin: .res 2 ; Y1 value of bounding box
XMax: .res 2 ; X2 value of bounding box
YMax: .res 2 ; Y2 value of bounding box
Buttons: .res 1 ; Button mask
; Temporary value used in the int handler
Temp: .res 1
.rodata
; Default values for above variables
; (We use ".proc" because we want to define both a label and a scope.)
.proc DefVars
.word SCREEN_HEIGHT/2 ; YPos
.word SCREEN_WIDTH/2 ; XPos
.word 0 ; XMin
.word 0 ; YMin
.word SCREEN_WIDTH - 1 ; XMax
.word SCREEN_HEIGHT - 1 ; YMax
.byte 0 ; Buttons
.endproc
.code
;----------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present.
; Must return an MOUSE_ERR_xx code in a/x.
INSTALL:
; Initialize variables. Just copy the default stuff over
ldx #.sizeof(DefVars)-1
@L1: lda DefVars,x
sta Vars,x
dex
bpl @L1
; Be sure the mouse cursor is invisible and at the default location. We
; need to do that here, because our mouse interrupt handler doesn't set the
; mouse position if it hasn't changed.
sei
jsr CHIDE
lda XPos
ldx XPos+1
jsr CMOVEX
lda YPos
ldx YPos+1
jsr CMOVEY
cli
; Done, return zero (= MOUSE_ERR_OK)
ldx #$00
txa
rts
;----------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; No return code required (the driver is removed from memory on return).
UNINSTALL = HIDE ; Hide cursor on exit
;----------------------------------------------------------------------------
; HIDE routine. Is called to hide the mouse pointer. The mouse kernel manages
; a counter for calls to show/hide, and the driver entry point is only called
; if the mouse is currently visible and should get hidden. For most drivers,
; no special action is required besides hiding the mouse cursor.
; No return code required.
HIDE: sei
jsr CHIDE
cli
rts
;----------------------------------------------------------------------------
; SHOW routine. Is called to show the mouse pointer. The mouse kernel manages
; a counter for calls to show/hide, and the driver entry point is only called
; if the mouse is currently hidden and should become visible. For most drivers,
; no special action is required besides enabling the mouse cursor.
; No return code required.
SHOW: sei
jsr CSHOW
cli
rts
;----------------------------------------------------------------------------
; SETBOX: Set the mouse bounding box. The parameters are passed as they come
; from the C program, that is, a pointer to a mouse_box struct in a/x.
; No checks are done if the mouse is currently inside the box, this is the job
; of the caller. It is not necessary to validate the parameters, trust the
; caller and save some code here. No return code required.
SETBOX: sta ptr1
stx ptr1+1 ; Save data pointer
ldy #.sizeof (MOUSE_BOX)-1
sei
@L1: lda (ptr1),y
sta XMin,y
dey
bpl @L1
cli
rts
;----------------------------------------------------------------------------
; GETBOX: Return the mouse bounding box. The parameters are passed as they
; come from the C program, that is, a pointer to a mouse_box struct in a/x.
GETBOX: sta ptr1
stx ptr1+1 ; Save data pointer
ldy #.sizeof (MOUSE_BOX)-1
@L1: lda XMin,y
sta (ptr1),y
dey
bpl @L1
rts
;----------------------------------------------------------------------------
; MOVE: Move the mouse to a new position. The position is passed as it comes
; from the C program, that is: X on the stack and Y in a/x. The C wrapper will
; remove the parameter from the stack on return.
; No checks are done if the new position is valid (within the bounding box or
; the screen). No return code required.
;
MOVE: sei ; No interrupts
sta YPos
stx YPos+1 ; New Y position
jsr CMOVEY ; Set it
ldy #$01
lda (sp),y
sta XPos+1
tax
dey
lda (sp),y
sta XPos ; New X position
jsr CMOVEX ; Move the cursor
cli ; Allow interrupts
rts
;----------------------------------------------------------------------------
; BUTTONS: Return the button mask in a/x.
BUTTONS:
lda Buttons
ldx #$00
rts
;----------------------------------------------------------------------------
; POS: Return the mouse position in the MOUSE_POS struct pointed to by ptr1.
; No return code required.
POS: ldy #MOUSE_POS::XCOORD ; Structure offset
sei ; Disable interrupts
lda XPos ; Transfer the position
sta (ptr1),y
lda XPos+1
iny
sta (ptr1),y
lda YPos
iny
sta (ptr1),y
lda YPos+1
cli ; Enable interrupts
iny
sta (ptr1),y ; Store last byte
rts ; Done
;----------------------------------------------------------------------------
; INFO: Returns mouse position and current button mask in the MOUSE_INFO
; struct pointed to by ptr1. No return code required.
;
; We're cheating here to keep the code smaller: The first fields of the
; mouse_info struct are identical to the mouse_pos struct, so we will just
; call _mouse_pos to initialize the struct pointer and fill the position
; fields.
INFO: jsr POS
; Fill in the button state
lda Buttons
ldy #MOUSE_INFO::BUTTONS
sta (ptr1),y
rts
;----------------------------------------------------------------------------
; IOCTL: Driver defined entry point. The wrapper will pass a pointer to ioctl
; specific data in ptr1, and the ioctl code in A.
; Must return an error code in a/x.
;
IOCTL: lda #<MOUSE_ERR_INV_IOCTL ; We don't support ioclts for now
ldx #>MOUSE_ERR_INV_IOCTL
rts
;----------------------------------------------------------------------------
; IRQ: Irq handler entry point. Called as a subroutine but in IRQ context
; (so be careful). The routine MUST return carry set if the interrupt has been
; 'handled' - which means that the interrupt source is gone. Otherwise it
; MUST return carry clear.
;
IRQ: jsr CPREP
; Avoid crosstalk between the keyboard and a joystick.
ldy #%00000000 ; Set ports A and B to input
sty CIA1_DDRB
sty CIA1_DDRA ; Keyboard won't look like joystick
lda CIA1_PRB ; Read Control-Port 1
dec CIA1_DDRA ; Set port A back to output
eor #%11111111 ; Bit goes up when switch goes down
beq @Save ;(bze)
dec CIA1_DDRB ; Joystick won't look like keyboard
sty CIA1_PRB ; Set "all keys pushed"
@Save: sta Temp
; Check for a pressed button and place the result into Buttons
ldx #$00 ; Assume no button pressed
and #JOY::FIRE ; Check fire button
beq @L0 ; Jump if not pressed
ldx #MOUSE_BTN_LEFT ; Left (only) button is pressed
@L0: stx Buttons
; Check left/right
lda Temp ; Read joystick #0
and #(JOY::LEFT | JOY::RIGHT)
beq @SkipX ;
; We will cheat here and rely on the fact that either the left, OR the right
; bit can be active
and #JOY::RIGHT ; Check RIGHT bit
bne @Right
lda #$FF
tax
bne @AddX ; Branch always
@Right: lda #$01
ldx #$00
; Calculate the new X coordinate (--> a/y)
@AddX: add XPos
tay ; Remember low byte
txa
adc XPos+1
tax
; Limit the X coordinate to the bounding box
cpy XMin
sbc XMin+1
bpl @L1
ldy XMin
ldx XMin+1
jmp @L2
@L1: txa
cpy XMax
sbc XMax+1
bmi @L2
ldy XMax
ldx XMax+1
@L2: sty XPos
stx XPos+1
; Move the mouse pointer to the new X pos
tya
jsr CMOVEX
; Calculate the Y movement vector
@SkipX: lda Temp ; Read joystick #0
and #(JOY::UP | JOY::DOWN) ; Check up/down
beq @SkipY ;
; We will cheat here and rely on the fact that either the up, OR the down
; bit can be active
lsr a ; Check UP bit
bcc @Down
lda #$FF
tax
bne @AddY
@Down: lda #$01
ldx #$00
; Calculate the new Y coordinate (--> a/y)
@AddY: add YPos
tay ; Remember low byte
txa
adc YPos+1
tax
; Limit the Y coordinate to the bounding box
cpy YMin
sbc YMin+1
bpl @L3
ldy YMin
ldx YMin+1
jmp @L4
@L3: txa
cpy YMax
sbc YMax+1
bmi @L4
ldy YMax
ldx YMax+1
@L4: sty YPos
stx YPos+1
; Move the mouse pointer to the new X pos
tya
jsr CMOVEY
; Done
@SkipY: jsr CDRAW
clc ; Interrupt not "handled"
rts