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Ensoniq noise improvements.

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Bobbi Webber-Manners 2022-11-25 21:34:08 -05:00
parent b2da3c705c
commit 002c0b79df
2 changed files with 16 additions and 12 deletions
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applecorn.po
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28
mainmem.ensq.s
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@ -44,12 +44,12 @@ ENSQINIT LDX #3
* Starts at $0100 in DOC RAM
LDA #210 ; High value of square wave
LDX #$00
:L3 STA ENSQSNDDAT ; 128 cycles of high value
:L3 STA ENSQSNDDAT ; 8 cycles of high value
INX
CPX #128
CPX #8
BNE :L3
LDA #40 ; Low value of square wave
:L4 STA ENSQSNDDAT ; 128 cycles of low value
:L4 STA ENSQSNDDAT ; 255-8 cycles of low value
INX
CPX #0
BNE :L4
@ -195,20 +195,20 @@ ENSQNOTE PHA
PLA ; Restore P
AND #$03 ; Keep least significant 2 bits
TAX
LDA #$40
:L1 CPX #$00
BEQ :S3
LSR
DEX
BRA :L1
TAY
LDA :NOISENOTE,Y ; BBC Micro note value
:S3 TAY ; Computed frequency value
:S3 PHA ; Gonna need it again
TAY ; Computed note
LDA EFREQHIGH,Y
TAY ; Frequency value LS byte
LDX #$20 ; Freq Hi Register
JSR ENSQWRTDOC
PLY ; Get computed note back
LDA EFREQLOW,Y
TAY ; Frequency value LS byte
LDX #$00 ; Freq Lo Register
LDY #$00 ; Value
JSR ENSQWRTDOC
LDX #$40 ; Amplitude Register
@ -218,6 +218,7 @@ ENSQNOTE PHA
LDX #$C0 ; Wavetable size Register
LDY #$04 ; Size 256, resolution 4
* LDY #$00 ; Size 256, resolution 1
JSR ENSQWRTDOC
LDX #$A0 ; Wavetable size Register
@ -228,6 +229,9 @@ ENSQNOTE PHA
PLX
PLA
RTS
:NOISENOTE DB 149 ; BBC Micro note P=0 or 4
DB 101 ; BBC Micro note P=1 or 5
DB 53 ; BBC Micro note P=2 or 6
* Adjust frequency of note already playing