Rex (Side A): Routine at D5E7

D5E7: Configure sound channel and mixer register

Used by the routines at 969B, 981F, 9AC5, 9C3B, 9D1F, 9D47, 9F5F, B506, B562, B64E, D215, D46C and D494.

Input
DE	Sound data address

D5E7

PUSH IY

Save IY, IX and BC

D5E9

PUSH IX

D5EB

PUSH BC

D5EC

PUSH DE

Copy DE into IY

D5ED

POP IY

D5EF

CALL $D5F8

Configure sound channel and mixer register

D5F2

POP BC

Restore IY, IX and BC

D5F3

POP IX

D5F5

POP IY

D5F7

RET

Configure sound channel and mixer register

D5F8

LD A,(IY+$00)

Set IX to the base address for the channel to configure

D5FB

DEC A

D5FC

SLA A

D5FE

SLA A

D600

SLA A

D602

LD C,A

D603

LD B,$00

D605

LD IX,$D832

D609

ADD IX,BC

D60B

LD A,(IY+$02)

Set number of tones

D60E

LD (IX+$00),A

D611

LD A,(IY+$06)

Set variation counter

D614

LD (IX+$01),A

D617

PUSH IY

Set address for sound data

D619

POP HL

D61A

LD BC,$0006

D61D

ADD HL,BC

D61E

LD (IX+$02),L

D621

LD (IX+$03),H

D624

LD A,(IY+$04)

Set base fine and coarse pitch

D627

LD (IX+$04),A

D62A

LD A,(IY+$05)

D62D

LD (IX+$05),A

D630

LD A,(IY+$03)

Set channel volume

D633

LD (IX+$07),A

D636

LD A,(IY+$01)

Set A to the data mixer

D639

CP $00

Jump forward if not zero

D63B

JP NZ,$D651

D63E

LD B,(IY+$00)

Disable noise for selected channel

D641

LD C,$04

D643

SLA C

D645

DJNZ $D643

D647

LD A,($D855)

Disable noise for the selected channel into the current data mixer

D64A

OR C

D64B

LD ($D855),A

D64E

JP $D682

Send this data to the mixer register

D651

LD A,($D855)

Set B the current data mixer

D654

LD B,A

D655

LD A,(IY+$00)

if channel 1 then disable tone in channel 1 and enable noise in channel 1

D658

CP $01

D65A

JP NZ,$D664

D65D

RES 3,B

D65F

SET 0,B

D661

JP $D674

Jump to update data mixer

D664

CP $02

if channel 2 then disable tone in channel 2 and enable noise in channel 2

D666

JP NZ,$D670

D669

RES 4,B

D66B

SET 1,B

D66D

JP $D674

Jump to update data mixer

D670

RES 5,B

if channel 3 then disable tone in channel 3 and enable noise in channel 3

D672

SET 2,B

D674

LD A,B

Update data mixer

D675

LD ($D855),A

D678

CALL $D682

Send this data to the mixer register

D67B

LD A,(IY+$01)

Copy noise/tone enable/disable

D67E

LD (IX+$06),A

D681

RET