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cc65/libsrc/c64/joy/c64-numpad.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

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3.3 KiB
ArmAsm

;
; Joystick driver using C128 number pad in 64 mode.
; May be used multiple times when linked to the statically application.
;
; Stefan Haubenthal, 2004-01-26
; Based on Ullrich von Bassewitz, 2002-12-20
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "c64.inc"
.macpack generic
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _c64_numpad_joy
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Library reference
.addr $0000
; Button state masks (8 values)
.byte $02 ; JOY_UP "8"
.byte $10 ; JOY_DOWN "2"
.byte $20 ; JOY_LEFT "4"
.byte $08 ; JOY_RIGHT "6"
.byte $04 ; JOY_FIRE "5" ENTER
.byte $00 ; JOY_FIRE2 unavailable
.byte $00 ; Future expansion
.byte $00 ; Future expansion
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READ
.addr 0 ; IRQ entry unused
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 1 ; Number of joysticks we support
; ------------------------------------------------------------------------
; Data.
.code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present and determine the amount of
; memory available.
; Must return an JOY_ERR_xx code in a/x.
;
INSTALL:
lda #JOY_ERR_OK ; Assume we have a joystick
ldx VIC_CLK_128 ; Test for a C128
cpx #$FF
bne @C128 ; Jump if we have one
lda #JOY_ERR_NO_DEVICE ; No C128 -> no numpad
@C128: ldx #0 ; Set high byte
; 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 #0
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READ: tax ; Clear high byte
lda #$FD
ldy #$FE
sei
sta VIC_KBD_128
lda CIA1_PRB
and #%00110000
eor #%00110000
lsr
lsr
sty VIC_KBD_128
eor CIA1_PRB
iny
sty VIC_KBD_128 ; Reset to $FF
cli
and #%11111110
eor #%11111110
rts