dos33fsprogs/music/chiptune_debug/chiptune_bare.s

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; VMW Chiptune Player
.include "zp.inc"
;=============================
; Setup
;=============================
;============================
; Init the Mockingboard
;============================
jsr mockingboard_init
jsr reset_ay_both
jsr clear_ay_both
;=========================
; Setup Interrupt Handler
;=========================
; Vector address goes to 0x3fe/0x3ff
lda #<interrupt_handler
sta $03fe
lda #>interrupt_handler
sta $03ff
;============================
; Enable 50Hz clock on 6522
;============================
sei ; disable interrupts just in case
lda #$40 ; Continuous interrupts, don't touch PB7
sta $C40B ; ACR register
lda #$7F ; clear all interrupt flags
sta $C40E ; IER register (interrupt enable)
lda #$C0
sta $C40D ; IFR: 1100, enable interrupt on timer one oflow
sta $C40E ; IER: 1100, enable timer one interrupt
lda #$E7
sta $C404 ; write into low-order latch
lda #$4f
sta $C405 ; write into high-order latch,
; load both values into counter
; clear interrupt and start counting
; 4fe7 / 1e6 = .020s, 50Hz
;==================
; load first song
;==================
;=========================
; Init Variables
;=========================
lda #$0
sta MB_CHUNK_OFFSET
lda #3
sta CHUNKSIZE
;===========================
; Load in KRW file
;===========================
lda #<UNPACK_BUFFER ; set input pointer
sta INL
lda #>UNPACK_BUFFER
sta INH
2018-06-11 20:59:56 +00:00
;============================
; Enable 6502 interrupts
;============================
cli ; clear interrupt mask
;============================
; Loop forever
;============================
main_loop:
jmp main_loop
;=========
;routines
;=========
2018-06-11 20:59:56 +00:00
; 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
;================================
;================================
; mockingboard interrupt handler
;================================
;================================
interrupt_handler:
pha ; save A ; 3
; Should we save X and Y too?
bit $C404 ; clear 6522 interrupt by reading T1C-L ; 4
mb_play_music:
;======================================
; Write frames to Mockingboard
;======================================
; actually plays frame loaded at end of
; last interrupt, so 20ms behind?
mb_write_frame:
ldx #0 ; set up reg count ; 2
;============
; 2
;==================================
; loop through the 14 registers
; reading the value, then write out
;==================================
; CHANNEL A LOW
mb_write_loop_0:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_0 ; 3/2nt
mb_write_0:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_0:
inx ; point to next register ; 2
; CHANNEL A HIGH
mb_write_loop_1:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_1 ; 3/2nt
mb_write_1:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_1:
inx ; point to next register ; 2
; CHANNEL B LOW
mb_write_loop_2:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_2 ; 3/2nt
mb_write_2:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_2:
inx ; point to next register ; 2
; CHANNEL B HIGH
mb_write_loop_3:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_3 ; 3/2nt
mb_write_3:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_3:
inx ; point to next register ; 2
; C CHANNEL LOW
mb_write_loop_4:
lda REGISTER_DUMP,X ; load register value ; 4
cmp REGISTER_OLD,X ; compare with old values ; 4
beq mb_no_write_4 ; 3/2nt
mb_write_4:
; address
stx MOCK_6522_ORA1 ; put address on PA1 ; 4
stx MOCK_6522_ORA2 ; put address on PA2 ; 4
lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
; value
lda REGISTER_DUMP,X ; load register value ; 4
sta MOCK_6522_ORA1 ; put value on PA1 ; 4
sta MOCK_6522_ORA2 ; put value on PA2 ; 4
lda #MOCK_AY_WRITE ; ; 2
sta MOCK_6522_ORB1 ; write on PB1 ; 4
sta MOCK_6522_ORB2 ; write on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_4:
inx ; point to next register ; 2
; C CHANNEL HIGH
mb_write_loop_5:
lda REGISTER_DUMP,X ; load register value ; 4
cmp REGISTER_OLD,X ; compare with old values ; 4
beq mb_no_write_5 ; 3/2nt
mb_write_5:
; address
stx MOCK_6522_ORA1 ; put address on PA1 ; 4
stx MOCK_6522_ORA2 ; put address on PA2 ; 4
lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
; value
lda REGISTER_DUMP,X ; load register value ; 4
sta MOCK_6522_ORA1 ; put value on PA1 ; 4
sta MOCK_6522_ORA2 ; put value on PA2 ; 4
lda #MOCK_AY_WRITE ; ; 2
sta MOCK_6522_ORB1 ; write on PB1 ; 4
sta MOCK_6522_ORB2 ; write on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_5:
inx ; point to next register ; 2
; NOISE PERIOD
mb_write_loop_6:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_6 ; 3/2nt
mb_write_6:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_6:
inx ; point to next register ; 2
; ENABLE
mb_write_loop_7:
lda REGISTER_DUMP,X ; load register value ; 4
cmp REGISTER_OLD,X ; compare with old values ; 4
beq mb_no_write_7 ; 3/2nt
mb_write_7:
; address
stx MOCK_6522_ORA1 ; put address on PA1 ; 4
stx MOCK_6522_ORA2 ; put address on PA2 ; 4
lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
; value
lda REGISTER_DUMP,X ; load register value ; 4
sta MOCK_6522_ORA1 ; put value on PA1 ; 4
sta MOCK_6522_ORA2 ; put value on PA2 ; 4
lda #MOCK_AY_WRITE ; ; 2
sta MOCK_6522_ORB1 ; write on PB1 ; 4
sta MOCK_6522_ORB2 ; write on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_7:
inx ; point to next register ; 2
; A amplitude
mb_write_loop_8:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_8 ; 3/2nt
mb_write_8:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_8:
inx ; point to next register ; 2
; B Amplitude
mb_write_loop_9:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_9 ; 3/2nt
mb_write_9:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; ;===========
; 62
mb_no_write_9:
inx ; point to next register ; 2
; C Amplitude
mb_write_loop_10:
lda REGISTER_DUMP,X ; load register value ; 4
cmp REGISTER_OLD,X ; compare with old values ; 4
beq mb_no_write_10 ; 3/2nt
mb_write_10:
; address
stx MOCK_6522_ORA1 ; put address on PA1 ; 4
stx MOCK_6522_ORA2 ; put address on PA2 ; 4
lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
; value
lda REGISTER_DUMP,X ; load register value ; 4
sta MOCK_6522_ORA1 ; put value on PA1 ; 4
sta MOCK_6522_ORA2 ; put value on PA2 ; 4
lda #MOCK_AY_WRITE ; ; 2
sta MOCK_6522_ORB1 ; write on PB1 ; 4
sta MOCK_6522_ORB2 ; write on PB2 ; 4
lda #MOCK_AY_INACTIVE ; go inactive ; 2
sta MOCK_6522_ORB1 ; 4
sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_10:
inx ; point to next register ; 2
mb_write_loop_11:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_11 ; 3/2nt
mb_write_11:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_11:
inx ; point to next register ; 2
mb_write_loop_12:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_12 ; 3/2nt
mb_write_12:
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_12:
inx ; point to next register ; 2
;mb_write_loop_13:
; lda REGISTER_DUMP,X ; load register value ; 4
; cmp REGISTER_OLD,X ; compare with old values ; 4
; beq mb_no_write_13 ; 3/2nt
;mb_write_13:
; special case R13. If it is 0xff, then don't update
; otherwise might spuriously reset the envelope settings
; cmp #$ff ; 2
; beq mb_no_write_13 ; 3/2nt
; address
; stx MOCK_6522_ORA1 ; put address on PA1 ; 4
; stx MOCK_6522_ORA2 ; put address on PA2 ; 4
; lda #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
; sta MOCK_6522_ORB1 ; latch_address on PB1 ; 4
; sta MOCK_6522_ORB2 ; latch_address on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
; value
; lda REGISTER_DUMP,X ; load register value ; 4
; sta MOCK_6522_ORA1 ; put value on PA1 ; 4
; sta MOCK_6522_ORA2 ; put value on PA2 ; 4
; lda #MOCK_AY_WRITE ; ; 2
; sta MOCK_6522_ORB1 ; write on PB1 ; 4
; sta MOCK_6522_ORB2 ; write on PB2 ; 4
; lda #MOCK_AY_INACTIVE ; go inactive ; 2
; sta MOCK_6522_ORB1 ; 4
; sta MOCK_6522_ORB2 ; 4
;===========
; 62
mb_no_write_13:
;=====================================
; Copy registers to old
;=====================================
ldx #13 ; 2
mb_reg_copy:
lda REGISTER_DUMP,X ; load register value ; 4
sta REGISTER_OLD,X ; compare with old values ; 4
dex ; 2
bpl mb_reg_copy ; 2nt/3
;=============
; 171
;===================================
; Load all 14 registers in advance
;===================================
; note, assuming not cross page boundary, not any slower
; then loading from zero page?
mb_load_values:
ldx #0 ; set up reg count ; 2
ldy MB_CHUNK_OFFSET ; get chunk offset ; 3
;=============
; 5
mb_load_loop:
lda (INL),y ; load register value ; 5
sta REGISTER_DUMP,X ; 4
;============
; 9
;====================
; point to next page
;====================
clc ; point to next interleaved ; 2
lda INH ; page by adding CHUNKSIZE (3/1); 3
adc CHUNKSIZE ; 3
sta INH ; 3
inx ; point to next register ; 2
cpx #14 ; if 14 we're done ; 2
bmi mb_load_loop ; otherwise, loop ; 3/2nt
;============
; 18
;==============================================
; incremement offset. If 0 move to next chunk
;==============================================
increment_offset:
inc MB_CHUNK_OFFSET ; increment offset ; 5
lda #0 ; 2
clc ; 2
adc #>UNPACK_BUFFER ; in proper chunk 1 or 2 ; 2
sta INH ; update r0 pointer ; 3
;=================================
; Finally done with this interrupt
;=================================
done_interrupt:
pla ; restore a ; 4
rti ; return from interrupt ; 6
2018-06-11 20:59:56 +00:00
REGISTER_OLD:
.byte 0,0,0,0,0,0,0,0,0,0,0,0,0,0
.align 256
UNPACK_BUFFER:
.incbin "sdemo.raw"