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Code optimizations (by Stefan Haubenthal and me).

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git-svn-id: svn://svn.cc65.org/cc65/trunk@3906 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-01-06 17:49:29 +00:00
parent 368e881288
commit 8c8e0b131f
1 changed files with 44 additions and 49 deletions
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93
libsrc/nes/nes-stdjoy.s
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@ -6,46 +6,46 @@
; Stefan Haubenthal, 2004-10-05
;
.include "zeropage.inc"
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "nes.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "nes.inc"
; ------------------------------------------------------------------------
; Header. Includes jump table
.segment "JUMPTABLE"
.segment "JUMPTABLE"
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Button state masks (8 values)
.byte $08 ; JOY_UP
.byte $04 ; JOY_DOWN
.byte $02 ; JOY_LEFT
.byte $01 ; JOY_RIGHT
.byte $80 ; JOY_FIRE (A)
.byte $40 ; JOY_FIRE2 (B)
.byte $20 ; JOY_FIRE3 (Select)
.byte $10 ; JOY_FIRE4 (Start)
.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
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READJOY
.addr 0 ; IRQ entry unused
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 2 ; Number of joysticks we support
JOY_COUNT = 2 ; Number of joysticks we support
.code
@ -58,9 +58,9 @@ JOY_COUNT = 2 ; Number of joysticks we support
;
INSTALL:
lda #JOY_ERR_OK
ldx #0
; rts ; Run into UNINSTALL instead
lda #JOY_ERR_OK
ldx #0
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
@ -68,7 +68,7 @@ INSTALL:
;
UNINSTALL:
rts
rts
; ------------------------------------------------------------------------
@ -76,37 +76,32 @@ UNINSTALL:
;
COUNT:
lda #JOY_COUNT
ldx #0
rts
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
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
lda #1
sta APU_PAD1,y
lda #0
sta APU_PAD1,y
sta tmp1
ldx #8
@Loop: lda APU_PAD1,y
ror a
ror tmp1
dex
bne @Loop
ldx #8
@L1: asl tmp1
lda APU_PAD1,y
and #$01
beq @L2
lda tmp1
ora #$01
sta tmp1
@L2: dex
bne @L1
lda tmp1
; ldx #$00 ; fix X
rts
lda tmp1
; ldx #$00 ; X implicitly fixed
rts