mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-11-18 21:06:31 +00:00
110 lines
2.5 KiB
ArmAsm
110 lines
2.5 KiB
ArmAsm
|
|
|
|
pt3_irq_handler:
|
|
|
|
bit $C404 ; clear 6522 interrupt by reading T1C-L ; 4
|
|
|
|
lda DONE_PLAYING ; 3
|
|
beq pt3_play_music ; if song done, don't play music ; 3/2nt
|
|
jmp done_pt3_irq_handler ; 3
|
|
;============
|
|
; 13
|
|
|
|
pt3_play_music:
|
|
|
|
; decode a frame of music
|
|
|
|
jsr pt3_make_frame
|
|
|
|
; handle song over condition
|
|
lda DONE_SONG
|
|
beq mb_write_frame ; if not done, continue
|
|
|
|
lda LOOP ; see if looping
|
|
beq move_to_next
|
|
|
|
pt3_loop_smc:
|
|
lda #$d1 ; looping, move to loop location
|
|
; non-zero to avoid the temptation
|
|
; to merge with following lda #$0
|
|
sta current_pattern_smc+1
|
|
lda #$0
|
|
sta current_line_smc+1
|
|
sta current_subframe_smc+1
|
|
sta DONE_SONG ; undo the next song
|
|
|
|
beq done_pt3_irq_handler ; branch always
|
|
|
|
move_to_next:
|
|
; same as "press right"
|
|
ldx #$20
|
|
jmp quiet_exit
|
|
|
|
;======================================
|
|
; Write frames to Mockingboard
|
|
;======================================
|
|
; for speed could merge this into
|
|
; the decode code
|
|
|
|
mb_write_frame:
|
|
|
|
|
|
tax ; set up reg count ; 2
|
|
;============
|
|
; 2
|
|
|
|
;==================================
|
|
; loop through the 14 registers
|
|
; reading the value, then write out
|
|
;==================================
|
|
|
|
mb_write_loop:
|
|
lda AY_REGISTERS,X ; load register value ; 4
|
|
|
|
; special case R13. If it is 0xff, then don't update
|
|
; otherwise might spuriously reset the envelope settings
|
|
|
|
cpx #13 ; 2
|
|
bne mb_not_13 ; 3/2nt
|
|
cmp #$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
|
|
ldy #MOCK_AY_LATCH_ADDR ; latch_address for PB1 ; 2
|
|
sty MOCK_6522_ORB1 ; latch_address on PB1 ; 4
|
|
sty MOCK_6522_ORB2 ; latch_address on PB2 ; 4
|
|
ldy #MOCK_AY_INACTIVE ; go inactive ; 2
|
|
sty MOCK_6522_ORB1 ; 4
|
|
sty MOCK_6522_ORB2 ; 4
|
|
|
|
; value
|
|
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
|
|
sty MOCK_6522_ORB1 ; 4
|
|
sty MOCK_6522_ORB2 ; 4
|
|
;===========
|
|
; 56
|
|
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:
|
|
|
|
|
|
;=================================
|
|
; Finally done with this interrupt
|
|
;=================================
|
|
|
|
done_pt3_irq_handler:
|