mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-08-18 23:29:26 +00:00
165 lines
3.9 KiB
ArmAsm
165 lines
3.9 KiB
ArmAsm
;================================
|
|
;================================
|
|
; mockingboard interrupt handler
|
|
;================================
|
|
;================================
|
|
|
|
interrupt_handler:
|
|
pha ; save A ; 3
|
|
; Should we save X and Y too?
|
|
|
|
.ifdef NOIRQ
|
|
.else
|
|
bit $C404 ; clear 6522 interrupt by reading T1C-L ; 4
|
|
.endif
|
|
|
|
mb_play_music:
|
|
|
|
|
|
;======================================
|
|
; Write frames to Mockingboard
|
|
;======================================
|
|
; actually plays frame loaded at end of
|
|
; last interrupt, so 20ms behind?
|
|
|
|
mb_write_frame:
|
|
|
|
|
|
ldx #0 ; set up reg count ; 2
|
|
;============
|
|
; 2
|
|
|
|
;==================================
|
|
; loop through the 14 registers
|
|
; reading the value, then write out
|
|
;==================================
|
|
; inlined "write_ay_both" to save up to 156 (12*13) cycles
|
|
; unrolled
|
|
|
|
mb_write_loop:
|
|
lda REGISTER_DUMP,X ; load register value ; 4
|
|
cmp REGISTER_OLD,X ; compare with old values ; 4
|
|
beq mb_no_write ; 3/2nt
|
|
;=============
|
|
; typ 11
|
|
|
|
; special case R13. If it is 0xff, then don't update
|
|
; otherwise might spuriously reset the envelope settings
|
|
|
|
cpx #13 ; 2
|
|
bne mb_not_13 ; 3/2nt
|
|
cmp #$ff ; 2
|
|
beq mb_skip_13 ; 3/2nt
|
|
;============
|
|
; typ 5
|
|
mb_not_13:
|
|
|
|
|
|
; 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:
|
|
inx ; point to next register ; 2
|
|
cpx #14 ; if 14 we're done ; 2
|
|
bmi mb_write_loop ; otherwise, loop ; 3/2nt
|
|
;============
|
|
; 7
|
|
mb_skip_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
|
|
.ifdef NOIRQ
|
|
rts
|
|
.else
|
|
rti ; return from interrupt ; 6
|
|
.endif
|
|
|
|
REGISTER_OLD:
|
|
.byte 0,0,0,0,0,0,0,0,0,0,0,0,0,0
|