mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-11-01 01:06:33 +00:00
145 lines
3.6 KiB
ArmAsm
145 lines
3.6 KiB
ArmAsm
; left speaker
|
|
MOCK_6522_ORB1 EQU $C400 ; 6522 #1 port b data
|
|
MOCK_6522_ORA1 EQU $C401 ; 6522 #1 port a data
|
|
MOCK_6522_DDRB1 EQU $C402 ; 6522 #1 data direction port B
|
|
MOCK_6522_DDRA1 EQU $C403 ; 6522 #1 data direction port A
|
|
|
|
; right speaker
|
|
MOCK_6522_ORB2 EQU $C480 ; 6522 #2 port b data
|
|
MOCK_6522_ORA2 EQU $C481 ; 6522 #2 port a data
|
|
MOCK_6522_DDRB2 EQU $C482 ; 6522 #2 data direction port B
|
|
MOCK_6522_DDRA2 EQU $C483 ; 6522 #2 data direction port A
|
|
|
|
; AY-3-8910 commands on port B
|
|
; RESET BDIR BC1
|
|
MOCK_AY_RESET EQU $0 ; 0 0 0
|
|
MOCK_AY_INACTIVE EQU $4 ; 1 0 0
|
|
MOCK_AY_READ EQU $5 ; 1 0 1
|
|
MOCK_AY_WRITE EQU $6 ; 1 1 0
|
|
MOCK_AY_LATCH_ADDR EQU $7 ; 1 1 1
|
|
|
|
|
|
;========================
|
|
; Mockingboard Init
|
|
;========================
|
|
; Initialize the 6522s
|
|
; set the data direction for all pins of PortA/PortB to be output
|
|
|
|
mockingboard_init:
|
|
lda #$ff ; all output (1)
|
|
sta MOCK_6522_DDRB1
|
|
sta MOCK_6522_DDRA1
|
|
sta MOCK_6522_DDRB2
|
|
sta MOCK_6522_DDRA2
|
|
rts
|
|
|
|
;======================
|
|
; Reset Left AY-3-8910
|
|
;======================
|
|
reset_ay_both:
|
|
lda #MOCK_AY_RESET
|
|
sta MOCK_6522_ORB1
|
|
lda #MOCK_AY_INACTIVE
|
|
sta MOCK_6522_ORB1
|
|
|
|
;======================
|
|
; Reset Right AY-3-8910
|
|
;======================
|
|
;reset_ay_right:
|
|
lda #MOCK_AY_RESET
|
|
sta MOCK_6522_ORB2
|
|
lda #MOCK_AY_INACTIVE
|
|
sta MOCK_6522_ORB2
|
|
rts
|
|
|
|
|
|
; Write sequence
|
|
; Inactive -> Latch Address -> Inactive -> Write Data -> Inactive
|
|
|
|
;=========================================
|
|
; Write Right/Left to save value AY-3-8910
|
|
;=========================================
|
|
; register in X
|
|
; value in MB_VALUE
|
|
|
|
write_ay_both:
|
|
; address
|
|
stx MOCK_6522_ORA1 ; put address on PA1 ; 3
|
|
stx MOCK_6522_ORA2 ; put address on PA2 ; 3
|
|
lda #MOCK_AY_LATCH_ADDR ; latch_address on PB1 ; 2
|
|
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 3
|
|
sta MOCK_6522_ORB2 ; latch_address on PB2 ; 3
|
|
lda #MOCK_AY_INACTIVE ; go inactive ; 2
|
|
sta MOCK_6522_ORB1 ; 3
|
|
sta MOCK_6522_ORB2 ; 3
|
|
|
|
; value
|
|
lda MB_VALUE ; 3
|
|
sta MOCK_6522_ORA1 ; put value on PA1 ; 3
|
|
sta MOCK_6522_ORA2 ; put value on PA2 ; 3
|
|
lda #MOCK_AY_WRITE ; ; 2
|
|
sta MOCK_6522_ORB1 ; write on PB1 ; 3
|
|
sta MOCK_6522_ORB2 ; write on PB2 ; 3
|
|
lda #MOCK_AY_INACTIVE ; go inactive ; 2
|
|
sta MOCK_6522_ORB1 ; 3
|
|
sta MOCK_6522_ORB2 ; 3
|
|
|
|
rts ; 6
|
|
;===========
|
|
; 53
|
|
;=======================================
|
|
; clear ay -- clear all 14 AY registers
|
|
; should silence the card
|
|
;=======================================
|
|
clear_ay_both:
|
|
ldx #14
|
|
lda #0
|
|
sta MB_VALUE
|
|
clear_ay_left_loop:
|
|
jsr write_ay_both
|
|
dex
|
|
bpl clear_ay_left_loop
|
|
rts
|
|
|
|
|
|
|
|
;=======================================
|
|
; Detect a Mockingboard card in Slot4
|
|
;=======================================
|
|
; Based on code from the French Touch "Pure Noise" Demo
|
|
; Attempts to time an instruction sequence with a 6522
|
|
;
|
|
; MB_ADDRL:MB_ADDRH has address of Mockingboard
|
|
; returns X=0 if not found, X=1 if found
|
|
|
|
mockingboard_detect_slot4:
|
|
lda #0
|
|
sta MB_ADDRL
|
|
|
|
mb4_detect_loop: ; self-modifying
|
|
lda #$04 ; we're only looking in Slot 4
|
|
ora #$C0 ; make it start with C
|
|
sta MB_ADDRH
|
|
ldy #04 ; $CX04
|
|
ldx #02 ; 2 tries?
|
|
mb4_check_cycle_loop:
|
|
lda (MB_ADDRL),Y ; timer 6522 (Low Order Counter)
|
|
; count down
|
|
sta TEMP ; 3 cycles
|
|
lda (MB_ADDRL),Y ; + 5 cycles = 8 cycles
|
|
; between the two accesses to the timer
|
|
sec
|
|
sbc TEMP ; subtract to see if we had 8 cycles
|
|
cmp #$f8 ; -8
|
|
bne mb4_not_in_this_slot
|
|
dex ; decrement, try one more time
|
|
bne mb4_check_cycle_loop ; loop detection
|
|
inx ; Mockingboard found (X=1)
|
|
done_mb4_detect:
|
|
rts ; return
|
|
|
|
mb4_not_in_this_slot:
|
|
ldx #00
|
|
beq done_mb4_detect
|
|
|