dos33fsprogs/music/ssi-263/ssi263_speech.s
2021-09-14 00:33:45 -04:00

217 lines
3.4 KiB
ArmAsm

;========================
; ssi263_write_chip
;========================
ssi263_write_chip:
wc_smc1:
sta $C000,X
rts
;========================
; read_chip
;========================
ssi263_read_chip:
rc_smc1:
lda $C000,X
rts
;========================
; ssi263_speech_init
;========================
; A = slot number of mockingboard
ssi263_speech_init:
sei ; disable interrupts
and #$7
ora #$c0 ; turn slot number into address
sta wc_smc1+2 ; update the read/write routines
sta rc_smc1+2
lda #<ssi263_speech_irq ; point IRQ handler to our code
sta $3fe
lda #>ssi263_speech_irq
sta $3ff
cli ; enable interrupts
rts
;============================
; ssi263_speech_shutdown
;============================
ssi263_speech_shutdown:
sei
rts
;=========================
; ssi263_speak
;=========================
; pointer to data in SPEECH_PTRL/H
ssi263_speak:
sei ; disable interrupts
; Set the busy flag
lda #$FF
sta speech_busy
; Set peripheral control register to recognize the signal from the
; speech chip.
lda #(VIA6522_PCR2_CA2_LOW|VIA6522_PCR2_CA1_NEG)
ldx #VIA6522_PCR2
jsr ssi263_write_chip
; Se transitioned inflection by setting value while toggling CTL
lda #SSI263_CAA_CTL
ldx #SSI263_CAA
jsr ssi263_write_chip
; Set transitioned inflection mode in register 0
lda #SSI263_DRP_TRANSITIONED_INFLECTION
ldx #SSI263_DRP
jsr ssi263_write_chip
; Lower control bit
lda #$70 ; also T=7
ldx #SSI263_CAA
jsr ssi263_write_chip
; Enable 6522 interrupts
lda #(VIA6522_IER2_SET|VIA6522_IER2_CA1)
ldx #VIA6522_IER2
jsr ssi263_write_chip
cli ; re-enable interrupts
rts
;====================
; speech interrupt
;====================
ssi263_speech_irq:
php ; save flags
cld
pha ; save A
txa
pha ; save X
tya
pha ; save Y
inc $0404 ; irq indicator on screen
; be sure it was a 6522#2 interrupt
ldx #VIA6522_IFR2
jsr ssi263_read_chip
bmi have_interrupt
; wasn't us, return to caller
; this assumes we can handle multiple interrupt sources
jmp end_interrupt
have_interrupt:
; Clear the 6522#2 CA interrupt flag
lda #VIA6522_IFR2_CA1
ldx #VIA6522_IFR2
jsr ssi263_write_chip
; Check if done with speech
ldy #0
lda (SPEECH_PTRL),Y
cmp #$ff
beq speech_end
not_end:
; Set the speech playing flag
lda #$ff
sta speech_playing
; Init registers
ldy #$00
ldx #SSI263_F ; start at end
register_loop:
; Get the next data
lda (SPEECH_PTRL),Y
; Store in the speech chip
jsr ssi263_write_chip
; Next data (inc 16 bit)
inc SPEECH_PTRL
bne no_oflo
inc SPEECH_PTRH
no_oflo:
; Go to next register
dex
; If we are not done the last register, then loop back to register loop
cpx #SSI263_BASE-1
bne register_loop
; Finish the interrupt handler
jmp end_interrupt
speech_end:
; If at the end, turn everything off
; Toggle CTL while DR set to disable A/!R
lda #SSI263_CAA_CTL
ldx #SSI263_CAA
jsr ssi263_write_chip
lda #SSI263_DRP_DISABLE_AR
ldx #SSI263_DRP
jsr ssi263_write_chip
; Zero amplitude
lda #$70
ldx #SSI263_CAA
jsr ssi263_write_chip
; Clear busy and playing flags
lda #$00
sta speech_busy
sta speech_playing
; Re-enable interrupt in 6522
lda #VIA6522_IER2_CA1
ldx #VIA6522_IER2
jsr ssi263_write_chip
end_interrupt:
pla
tay ; restore Y
pla
tax ; restore X
pla ; restore A
interrupt_smc:
lda $45 ; restore A (II+/IIe)
plp ; restore flags
rti ; return from interrupt
speech_busy: .byte $00
speech_playing: .byte $00