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cc65/libsrc/atari/joy/atrstd.s
Oliver Schmidt 7f52a770d9 Removed joy_masks array.
So far the joy_masks array allowed several joystick drivers for a single target to each have different joy_read return values. However this meant that every call to joy_read implied an additional joy_masks lookup to post-process the return value.

Given that almost all targets only come with a single joystick driver this seems an inappropriate overhead. Therefore now the target header files contain constants matching the return value of the joy_read of the joystick driver(s) on that target.

If there indeed are several joystick drivers for a single target they must agree on a common return value for joy_read. In some cases this was alredy the case as there's a "natural" return value for joy_read. However a few joystick drivers need to be adjusted. This may cause some overhead inside the driver. But that is for sure smaller than the overhead introduced by the joy_masks lookup before.

!!! ToDo !!!

The following three joystick drivers become broken with this commit and need to be adjusted:
- atrmj8.s
- c64-numpad.s
- vic20-stdjoy.s
2017-08-19 19:11:28 +02:00

111 lines
2.7 KiB
ArmAsm

;
; Standard joystick driver for the Atari. May be used multiple times when linked
; to the statically application.
;
; Ullrich von Bassewitz, 2002-12-21
; Using the readjoy code from Christian Groessler
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "atari.inc"
.macpack generic
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
.ifdef __ATARIXL__
module_header _atrxstd_joy
.else
module_header _atrstd_joy
.endif
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Library reference
.addr $0000
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READJOY
.addr 0 ; IRQ entry not used
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 4 ; Number of joysticks we support
; ------------------------------------------------------------------------
; Data.
.code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present and determine the amount of
; memory available.
; Must return an JOY_ERR_xx code in a/x.
;
INSTALL:
lda #JOY_ERR_OK
ldx #0
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; Can do cleanup or whatever. Must not return anything.
;
UNINSTALL:
rts
; ------------------------------------------------------------------------
; COUNT: Return the total number of available joysticks in a/x.
;
COUNT:
lda #JOY_COUNT
ldx $fcd8
cpx #$a2
beq _400800
lsr a ; XL and newer machines only have 2 ports
_400800:
ldx #0
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READJOY:
and #3 ; fix joystick number
tax ; Joystick number (0-3) into X
; Read joystick
lda STRIG0,x ; get button
asl a
asl a
asl a
asl a
ora STICK0,x ; add position information
eor #$1F
ldx #0 ; fix X
rts