mockingboard: got ksp theme playing

This commit is contained in:
Vince Weaver 2018-02-03 23:45:38 -05:00
parent 54690d0f94
commit 4d54f1f1a7
2 changed files with 85 additions and 10 deletions

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@ -9,7 +9,7 @@
.include "zp.inc"
;=============================
; set low-res graphics, page 0
; Print message
;=============================
jsr HOME
jsr TEXT
@ -31,6 +31,9 @@
jsr mockingboard_init
jsr reset_ay_left
jsr reset_ay_right
jsr clear_ay_left
jsr clear_ay_right
;===========================
; load pointer to the music
@ -39,9 +42,48 @@
lda #<ksptheme
sta INL
lda #>ksptheme
sta OUTL
sta INH
ldx #0
frame_loop:
ldy #0
play_loop:
lda (INL),Y
tax
jsr write_ay_left ; assume 3 channel (not six)
jsr write_ay_right ; so write same to both left/write
iny
cpy #13
bne play_loop
; special case, if reg 13 = ff don't write it
lda (INL),Y
cmp #$ff
beq was_ff
jsr write_ay_left ; assume 3 channel (not six)
jsr write_ay_right ; so write same to both left/write
was_ff:
; see if at end
iny
iny
lda (INL),Y
cmp #$ff
beq done_play
; increment INL:INH by 13
clc
lda INL
adc #14
sta INL
lda INH
adc #0
sta INH
delay_a_bit:
@ -52,7 +94,14 @@ delay_a_bit:
; 40000 = 26+27A+5A^2
; 5a^2+27a-39974 = 0
; A = 86.75
jmp frame_loop
done_play:
jsr clear_ay_left
jsr clear_ay_right
lda #0
sta CH
lda #2
@ -139,19 +188,19 @@ reset_ay_right:
;=======================
; Write Right AY-3-8910
;=======================
; register in X
; value in Y
; register in Y
; value in X
write_right_ay:
write_ay_right:
; address
stx MOCK_6522_ORA1 ; put address on PA
sty MOCK_6522_ORA1 ; put address on PA
lda #MOCK_AY_LATCH_ADDR ; latch_address on PB
sta MOCK_6522_ORB1
lda #MOCK_AY_INACTIVE ; go inactive
sta MOCK_6522_ORB1
; value
sty MOCK_6522_ORA1 ; put value on PA
stx MOCK_6522_ORA1 ; put value on PA
lda #MOCK_AY_WRITE ; write on PB
sta MOCK_6522_ORB1
lda #MOCK_AY_INACTIVE ; go inactive
@ -165,16 +214,16 @@ write_right_ay:
; register in X
; value in Y
write_left_ay:
write_ay_left:
; address
stx MOCK_6522_ORA2 ; put address on PA
sty MOCK_6522_ORA2 ; put address on PA
lda #MOCK_AY_LATCH_ADDR ; latch_address on PB
sta MOCK_6522_ORB2
lda #MOCK_AY_INACTIVE ; go inactive
sta MOCK_6522_ORB2
; value
sty MOCK_6522_ORA2 ; put value on PA
stx MOCK_6522_ORA2 ; put value on PA
lda #MOCK_AY_WRITE ; write on PB
sta MOCK_6522_ORB2
lda #MOCK_AY_INACTIVE ; go inactive
@ -182,6 +231,32 @@ write_left_ay:
rts
;=======================================
; clear ay -- clear all 14 AY registers
; should silence the card
;=======================================
clear_ay_left:
ldy #14
ldx #0
clear_ay_left_loop:
jsr write_ay_left
dey
bpl clear_ay_left_loop
rts
;=======================================
; clear ay -- clear all 14 AY registers
; should silence the card
;=======================================
clear_ay_right:
ldy #14
ldx #0
clear_ay_right_loop:
jsr write_ay_right
dey
bpl clear_ay_right_loop
rts
;routines
.include "../asm_routines/gr_offsets.s"