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cc65/libsrc/nes/joy/nes-stdjoy.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

114 lines
2.9 KiB
ArmAsm

;
; Standard joypad driver for the NES. May be used multiple times when
; linked to the statically application.
;
; Ullrich von Bassewitz, 2003-05-02
; Stefan Haubenthal, 2004-10-05
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "nes.inc"
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _nes_stdjoy_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 $10 ; JOY_UP
.byte $20 ; JOY_DOWN
.byte $40 ; JOY_LEFT
.byte $80 ; JOY_RIGHT
.byte $01 ; JOY_FIRE (A)
.byte $02 ; JOY_FIRE2 (B)
.byte $04 ; (Select)
.byte $08 ; (Start)
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READJOY
.addr 0 ; IRQ entry unused
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 2 ; Number of joysticks we support
.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 #0
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READJOY:
and #$01 ; Fix joystick number
tay ; Joystick number (0,1) into Y
lda #1
sta APU_PAD1,y
lda #0
sta APU_PAD1,y
; Read joystick
ldx #8
@Loop: lda APU_PAD1,y
ror a
ror tmp1
dex
bne @Loop
lda tmp1
; ldx #$00 ; X implicitly fixed
rts