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More untested Ensoniq audio code.

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Bobbi Webber-Manners 2022-09-29 13:48:49 -04:00
parent ad8693244a
commit 75e0df40ea
1 changed files with 53 additions and 14 deletions
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67
auxmem.audio.s
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@ -133,10 +133,45 @@ WORD08
* Called from Ensoniq interrupt handler - process audio queue
*
ENSQIRQ
* TODO: IMPLEMENT THIS!!!
RTS
* Called at 100Hz
ENSQIRQ INC COUNTER ; Increment centisecond timer
INC :CNT ; Find every 5th cycle
CMP #5
BNE :NOT20HZ
STZ :CNT
LDX #3 ; Process four audio queues
:L1 LDA OSCTIMES,X ; Time remaining on current note
BEQ :NONOTE ; No note playing
DEC OSCTIMES,X
BRA :NOTE
:NONOTE LDY #$00 ; Zero volume
LDA #$00 ; Zero freq
JSR ENSQNOTE ; Silence channel Y
:NOTE CLV ; Means remove from queue
JSR REMHND ; Remove byte from queue
BCS :EMPTY ; Nothing in queue
PHY ; Amplitude
JSR REMHND ; Remove byte from queue
PHY ; Frequency
JSR REMHND ; Remove byte from queue
TYA ; Duration
STA OSCTIMES,X
PLA ; Recover frequency
PLY ; Recover amplitude
JSR ENSQNOTE ; Start note playing
:EMPTY DEX
BNE :L1 ; Next audio queue
:NOT20HZ
* TODO: Envelope processing on all cycles (AT 100Hz)
:RTS RTS
:CNT DB $00 ; Used to determine 20Hz cycles
COUNTER DW $0000 ; Centisecond counter
* Time remaining for current note, in 1/20th of second
OSCTIMES DB $00
DB $00
DB $00
DB $00
* Initialize Ensoniq
@ -167,21 +202,25 @@ ENSQINIT LDA ENSQSNDCTL ; Get settings
LDX #$E1 ; DOC Osc Enable register $E1
LDY #8 ; Four oscillators enabled
JSR ENSQWRTDOC
LDX #$00 ; Amplitude
; Fall through
* Silence all channels
ENSQSILENT LDY #$00 ; Amplitude
LDA #$80 ; Frequency
LDY #$03
:L3 JSR ENSQOSCIL ; Initialize channel Y
DEY
BPL :L3
LDX #$03
:L1 JSR ENSQNOTE ; Initialize channel Y
STZ OSCTIMES,X ; No note playing
DEX
BPL :L1
RTS
* Configure Ensoniq oscillator
* On entry: Y - oscillator number 0-3 , A - frequency, X - amplitude
* On entry: X - oscillator number 0-3 , A - frequency, Y - amplitude
* Preserves all registers
* TODO: ALWAYS USES OSCILLATOR CHANNEL 0 FOR NOW
ENSQOSCIL PHA
PHY
ENSQNOTE PHA
PHX
PHY
LDX #$00 ; DOC register $00 (Freq Lo)
TAY ; Frequency value LS byte
JSR ENSQWRTDOC
@ -189,7 +228,7 @@ ENSQOSCIL PHA
LDY #$00 ; Frequency value MS byte
JSR ENSQWRTDOC
LDX #$40 ; DOC register $40 (Volume)
PLY ; Frequency value orig in X
PLY ; Amplitude value
PHY
JSR ENSQWRTDOC
LDX #$80 ; DOC register $80 (Wavetable)
@ -201,8 +240,8 @@ ENSQOSCIL PHA
LDX #$C0 ; DOC register $C0 (WT size)
LDY #$00 ; For 256 byte wavetable
JSR ENSQWRTDOC
PLX
PLY
PLX
PLA
RTS