Playing 128k Spectrum (AY-3-8912) music on SAM (SAA1099)

From Dan Dooré

Cookies Hot Butter demo used 128K music - source is here: http://home.earthlink.net/~simoncooke/samcoupe/infobase/source/htbtter.txt and there’s a section called “Convert 128k Spectrum (AY-3-8912) music to SAM (SAA1099)” but given the only thing I know about Z80 is how to spell it I couldn’t say much more

From Stefan Drissen

The Cookie AY player is one routine that usually resides in the lower 16k bank. The largest chuck is a lookup table for converting AY frequencies to SAA frequencies (attached).

This routine or modifications (I disassembled it) has been used in all Speccy 128k demo conversions on the SAM.

ORG 0
DUMP 3,$

LD C,255 ;soundchip on
LD B,1
LD A,onoff
OUT (C),A
DEC B
LD A,1
OUT (C),A

DEFS $/256+1*256-$

;the outputs to the AY-3-8912’s registers are intercepted and
;are used as memory mapped i/o

memoryio:

ayfine1: DEFB 0
aycoarse1: DEFB 0
ayfine2: DEFB 0
aycoarse2: DEFB 0
ayfine3: DEFB 0
aycoarse3: DEFB 0
aynoisepitch: DEFB 0
aymixer: DEFB 0
ayvol1: DEFB 0
ayvol2: DEFB 0
ayvol3: DEFB 0
ayenvlength:
ayenvlen: DEFB 0
ayenvlen2: DEFB 0
ayenvshape: DEFB 0

saaouts:
DEFB tone2
saatone2: DEFB 0
DEFB amp2
saaamp2: DEFB 0
DEFB tone3
saatone3: DEFB 0
DEFB amp3
saaamp3: DEFB 0
DEFB oct32
saaoct32: DEFB 0
DEFB tone5
saatone5: DEFB 0
DEFB amp5
saaamp5: DEFB 0
DEFB oct54
saaoct54: DEFB 0
DEFB noisefreq
saanoisefreq: DEFB 0
DEFB freqen
saafreqen: DEFB 0
DEFB noiseen
saanoiseen: DEFB 0
DEFB onoff
DEFB 1

play.it:
LD HL,ayfine1
LD E,(HL) ;ayfine1
INC L
LD A,(HL) ;aycoarse1

AND 15
LD D,A

EX DE,HL
ADD HL,HL
LD DE,pitchconvert
ADD HL,DE

LD A,(HL)
LD (saatone2),A
INC L
LD A,(HL)
LD (stoctave1+1),A

LD HL,ayfine2
LD E,(HL) ;ayfine2
INC HL
LD A,(HL) ;aycoarse2
AND 15
LD D,A

EX DE,HL
ADD HL,HL
LD DE,pitchconvert
ADD HL,DE

LD A,(HL)
LD (saatone3),A
INC L
LD A,(HL)
RLCA
RLCA
RLCA
RLCA
stoctave1: OR 0
LD (saaoct32),A

LD HL,ayfine3
LD E,(HL) ;ayfine3
INC L
LD A,(HL) ;aycoarse3
AND 15
LD D,A

EX DE,HL
ADD HL,HL
LD DE,pitchconvert
ADD HL,DE

LD A,(HL)
LD (saatone5),A
INC L
LD A,(HL)
RLCA
RLCA
RLCA
RLCA
LD (saaoct54),A

LD A,(aynoisepitch)
LD HL,noiseconvert
ADD L
LD L,A
LD A,(HL)
LD (saanoisefreq),A

LD A,(aymixer)
LD DE,0
BIT 0,A
JR NZ,c2nsound
SET 2,D
c2nsound: BIT 3,A
JR NZ,c2nnoise
SET 2,E
c2nnoise: BIT 1,A
JR NZ,c3nsound
SET 3,D
c3nsound: BIT 4,A
JR NZ,c3nnoise
SET 3,E
c3nnoise: BIT 2,A
JR NZ,c5nsound
SET 5,D
c5nsound: BIT 5,A
JR NZ,c5nnoise
SET 5,E
c5nnoise:
LD A,D
LD (saafreqen),A
LD A,E
LD (saanoiseen),A

LD HL,ayvol1
LD A,(HL)
RLCA
RLCA
RLCA
RLCA
OR (HL)
LD (saaamp2),A

INC HL
LD A,(HL) ;chan2vol
RLCA
RLCA
RLCA
RLCA
OR (HL)
LD (saaamp3),A

INC HL ;chan3vol
LD A,(HL)
RLCA
RLCA
RLCA
RLCA
OR (HL)
LD (saaamp5),A

LD BC,&00FF
LD HL,saaouts
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
OUTI
RET

amp0: EQU 0
amp1: EQU 1
amp2: EQU 2
amp3: EQU 3
amp4: EQU 4
amp5: EQU 5

tone0: EQU 8
tone1: EQU 9
tone2: EQU 10
tone3: EQU 11
tone4: EQU 12
tone5: EQU 13

oct10: EQU 16
oct32: EQU 17
oct54: EQU 18

freqen: EQU 20
noiseen: EQU 21
noisefreq: EQU 22

env0: EQU 24
env1: EQU 25

onoff: EQU 28

noiseconvert: DEFB 0,0,0,0,0,0,17,17,17,17,17,17,17,17,17,17,34
DEFB 34,34,34,34,34,34,34,34,34,34,34,34,34,34,34

envconvert: DEFB 132,132,132,132,140,140,140,140
DEFB 134,132,138,130,142,130,138,140

pitchconvert: MDAT “AYtable.bin”

The attached aytable.bin is an 8k file containing the conversions.