; 4 channels sample player Z80 driver ; it can mix up to 4 samples (8 bit signed) at a fixed 16 Khz rate ; with volume support (16 levels du to memory limitation) ; address and size of samples have to be 256 bytes boundary ; the driver does support "cutoff" when mixing so you can use true 8 bits samples :) ; Stéphane Dallongeville @2011 ; ; we have to do 223 cycles per sample output which consist of : ; - read 4 samples from the rom and mix them in output buffer (~177 cycles) ; - output the obtained sample to the DAC (26 cycles) ; - handle loop (18 cycles) ; ; register usage : ; SP = sample source (in ROM) ; HL = mix buffer ; BC = $7F00 (used for mix overflow stuff) ; HL' = YMPORT0 ; BC' = read buffer ; ########################### define ############################## INCLUDE "z80_def.i80" ; basic definitions ; ########################### var ############################## WAVADR EQU PARAMS+$00 ; WAV address (bit 8 --> bit 23) WAVLEN EQU PARAMS+$02 ; WAV lenght (bit 8 --> bit 23) IWAVADR EQU PARAMS+$10 ; internal WAV address (bit 8 --> bit 23) IWAVLEN EQU PARAMS+$12 ; internal WAV lenght (bit 8 --> bit 23) WAVVOL EQU PARAMS+$20 ; WAV volume (0 = min --> 15 = max) NULLWAVADR EQU PARAMS+$24 ; silent WAV adr NULLWAVLEN EQU PARAMS+$26 ; silent WAV len WRITEBUF EQU PARAMS+$28 READBUF EQU PARAMS+$2A WAVBUFFER0 EQU $0E00 ; WAV buffer 0 WAVBUFFER1 EQU $0F00 ; WAV buffer 1 VOLUMETAB EQU $1000 ; volume table (256 * 16) ; ########################### macro ############################## INCLUDE "z80_mac.i80" ; basic macros ; copyChannelParams ; ----------------- ; copy channel parameters to internal structure ; = 64 cycles macro copyChannelParams ch LD HL, (WAVADR+(ch*4)) ; ' 16 LD (IWAVADR+(ch*4)), HL ; ' 16 LD HL, (WAVLEN+(ch*4)) ; ' 16 LD (IWAVLEN+(ch*4)), HL ; ' 16 endm ; ' 64 ; stopChannel ; ----------- ; set null sample play for channel 'ch' ; = 114 cycles macro stopChannel ch LD HL, (NULLWAVADR) ; ' 16 LD (IWAVADR+(ch*4)), HL ; ' 16 LD HL, (NULLWAVLEN) ; ' 16 LD (IWAVLEN+(ch*4)), HL ; ' 16 clearPlayStatus ch ; clear play status ' 25 clearLoopStatus ch ; clear loop status ' 25 endm ; ' 114 ; handlePlayCommand ; ----------------- ; HL <- ? ; DE <- ? ; ; handle play command for channel 'ch' ; = 146 cycles macro handlePlayCommand ch getPlayCommand ch ; play command ? ' 22 JP NZ, .do_command ; ' 10 (32) wait104 ; ' 104 (136) JP .end ; ' 10 (146) .do_command clearPlayCommand ch ; clear play command ' 25 (57) copyChannelParams ch ; copy params ' 64 setPlayStatus ch ; set play status ' 25 .end endm ; ' 146 ; prepareVolume ; ------------- ; HL <- ? ; A <- ? ; B <- point to volume LUT (high part) ; ; prepare B for volume ajustement ; = 28 cycles macro prepareVolume ch LD HL, WAVVOL+ch ; point to volume info ' 10 LD A, (HL) ; A = volume ' 7 OR $10 ; ajusted for LUT ' 7 LD B, A ; save to B ' 4 endm ; ' 28 ; prepareChannel ; -------------- ; SP <- point to the sample source ; HL <- point to write buffer ; A <- ? ; E <- ? ; ; set bank and prepare registers to play channel 'ch' ; = 182 cycles macro prepareChannel ch LD HL, IWAVADR+(ch*4) ; point to sample adr ' 10 LD A, (HL) ; A = bit 8-15 ' 7 LD E, A ; save to E ' 4 INC L ; ' 4 RLA ; C flag = bit 15 ' 4 LD A, (HL) ; A = bit 16-23 ' 7 RLA ; A = bit 15-22 ' 4 (40) setBankFast ; set bank ' 97 (137) LD A, E ; A = bit 8-15 ' 4 OR $80 ; A = $80 | bit 8-14 ' 7 LD H, A ; ' 4 XOR A ; ' 4 LD L, A ; L = $00 ' 4 LD SP, HL ; SP = sample src ' 6 LD HL, (WRITEBUF) ; ' 16 (182) endm ; ' 182 ; updateChannelData ; ----------------- ; HL <- ? ; ; update sample address and sample lenght ; = 76 cycles macro updateChannelData ch LD HL, (IWAVADR+(ch*4)) ; increment address ' 16 INC HL ; ' 6 LD (IWAVADR+(ch*4)), HL ; ' 16 (38) LD HL, (IWAVLEN+(ch*4)) ; decrement lenght ' 16 DEC HL ; ' 6 LD (IWAVLEN+(ch*4)), HL ; ' 16 (76) endm ; checkChannelEnd ; --------------- ; HL <- ? ; A <- ? ; ; check is sample is done, restart it if needed ; = 180 cycles macro checkChannelEnd ch LD HL, (IWAVLEN+(ch*4)) ; get sample lenght ' 16 LD A, H ; ' 4 OR L ; ' 4 JP Z, .done ; sample done ? ' 10 (34) wait136 ; ' 136 (170) JP .end ; ' 10 (180) .done getLoopStatus ch ; loop play ? ' 22 (56) JP Z, .stop ; ' 10 (66) copyChannelParams ch ; copy params ' 64 (130) wait40 ; ' 40 JP .end ; ' 10 (180) .stop stopChannel ch ; ' 114 (180) .end endm ; ' 180 ; swapBuffer ; ---------- ; HL <- point to new write buffer ; DE <- point to new read buffer ; ; switch read and write buffer ; = 72 cycles macro swapBuffer LD HL, (WRITEBUF) ; ' 16 LD DE, (READBUF) ; ' 20 LD (WRITEBUF), DE ; ' 20 LD (READBUF), HL ; ' 16 endm ; ' 72 ; sampleOutput ; ------------ ; HL' -> YMPORT1 ; BC' <-> point to play output buffer ; D -> $80 ; ; output a sample to the DAC ; = 30 cycles macro sampleOutput EXX ; ' 4 LD A, (BC) ; read sample from buffer ' 7 ADD D ; unsign ' 4 INC C ; increment with looping ' 4 LD (HL), A ; play sample ' 7 EXX ; ' 4 endm ; ' 30 ; doEnvAndClear ; = 18 cycles macro doEnvAndClear LD A, (BC) ; compute volume ' 7 LD (HL), A ; write in output buffer ' 7 INC L ; next ' 4 endm ; readAndClear2 ; ------------- ; SP <-> point to the sample source (ROM) ; HL <-> point to the write output buffer ; BC -> point to envelop LUT ; DE <- ? ; ; read 2 samples from the ROM, apply volume ; and write them in output buffer ; = 56 cycles macro readAndClear2 POP DE ; read 2 samples from ROM ' 10+2 LD C, E ; first sample ' 4 doEnvAndClear ; ' 18 LD C, D ; second sample ' 4 doEnvAndClear ; ' 18 endm ; ' 56 ; readAndClear20WhilePlay3 ; ------------------------ ; SP <-> point to the sample source (ROM) ; HL <-> point to the write output buffer ; BC -> point to envelop LUT ; DE <- ? ; ; read 20 samples from the ROM, apply volume ; and write them in output buffer while playing 3 samples ; = 666 cycles macro readAndClear20WhilePlay3 ; 1 -------------------- sampleOutput ; ' 30 readAndClear2 ; ' 56 | readAndClear2 ; ' 56 | 168 (198) readAndClear2 ; ' 56 | ; 4 -------------------- POP DE ; read 2 samples from ROM ' 10+2 | LD C, E ; first sample ' 4 | 25 (223) wait9 ; synchro ' 9 | sampleOutput ; (1*223)+0 --> perfect ' 30 (253) doEnvAndClear ; ' 18 | LD C, D ; second sample ' 4 | 40 (293) doEnvAndClear ; ' 18 | readAndClear2 ; ' 56 | 112 (405) readAndClear2 ; ' 56 | ; 7 -------------------- POP DE ; read 2 samples from ROM ' 10+2 | LD C, E ; first sample ' 4 | 34 (446) doEnvAndClear ; ' 18 | wait7 ; synchro ' 7 | sampleOutput ; (2*223)+0 --> perfect ' 30 (476) LD C, D ; second sample ' 4 | 22 (498) doEnvAndClear ; ' 18 | readAndClear2 ; ' 56 | readAndClear2 ; ' 56 | 168 (666) readAndClear2 ; ' 56 | endm ; ' 666 ; doEnvAndMix ; = 35 --> 49 cycles macro doEnvAndMix LD A, (BC) ; compute volume ' 7 | ADD (HL) ; mix ' 7 | 24 JP PO, .ok ; check overflow ' 10 | LD A, $7F ; fix overflow ' 7 | ADC $0 ; A = $7F/$80 ' 7 | +14 .ok LD (HL), A ; write sample in buffer ' 7 | 11 (35) INC L ; next ' 4 | endm ; readAndMix2 ; ----------- ; SP <-> point to the sample source (ROM) ; HL <-> point to the write output buffer ; BC -> point to envelop LUT ; DE <- ? ; A <- ? ; ; read 2 samples from the ROM, apply volume ; and mix them in output buffer ; = 90 --> 118 cycles macro readAndMix2 POP DE ; read 2 samples from ROM ' 10+2 LD C, E ; first sample ' 4 | doEnvAndMix ; ' 35 | 78 (90) LD C, D ; second sample ' 4 | doEnvAndMix ; ' 35 | endm ; ' 90 (+14/+28) ; readAndMix12WhilePlay3 ; ---------------------- ; SP <-> point to the sample source (ROM) ; HL <-> point to the write output buffer ; BC -> point to envelop LUT ; DE <- ? ; A <- ? ; ; read 12 samples from the ROM, apply volume ; and mix them in output buffer while playing 3 samples ; = 640 cycles macro readAndMix12WhilePlay3 ; 1 -------------------- sampleOutput ; ' 30 readAndMix2 ; ' 90 | 180 (210) readAndMix2 ; ' 90 | ; 3 -------------------- POP DE ; read 2 samples from ROM ' 10+2 (222) sampleOutput ; (1*223)-1 --> bit soon ' 30 (252) LD C, E ; first sample ' 4 | doEnvAndMix ; ' 35 | 78 (330) LD C, D ; second sample ' 4 | doEnvAndMix ; ' 35 | readAndMix2 ; ' 90 (420) ; 5 -------------------- POP DE ; read 2 samples from ROM ' 10+2 | LD C, E ; first sample ' 4 | 26 (446) wait10 ; synchro ' 10 | sampleOutput ; (2*223)+0 --> perfect ' 30 (476) doEnvAndMix ; ' 35 | LD C, D ; second sample ' 4 | 74 (550) doEnvAndMix ; ' 35 | readAndMix2 ; ' 90 (640) endm ; ' 640 ; ########################### init ############################## ORG $0000 init DI ; disable ints LD SP, $0E00 ; setup stack IM $01 ; set int mode 1 XOR A LD (STATUS), A ; driver not ready LD (COMMAND), A ; command cleared JP start ; jump to start ; ########################### interrupt ############################## BLOCK $0038-$ interrupt ; do nothing in this program RETI ; ########################### main ############################## BLOCK $0200-$ start LD HL, PARAMS LD A, $00 LD B, $20 cp_loop LD (HL), A ; clear sample parameters INC HL DJNZ cp_loop LD HL, WAVBUFFER0 LD A, $00 LD B, $00 ; for 256 * 2 bytes to clear cb_loop LD (HL), A ; initialise buffers to silent INC HL LD (HL), A INC HL DJNZ cb_loop CALL initDAC ; prepare DAC for output LD HL, WAVBUFFER0 ; initialise write and read buffer LD (WRITEBUF), HL LD HL, WAVBUFFER1 LD (READBUF), HL LD BC, HL ; BC' point to read buffer LD D, $80 ; D' = $80 (fast unsign) LD HL, YMPORT1 ; HL' point to YMPORT1 EXX wait_nullwav LD HL, (NULLWAVADR) LD A, H OR L JP Z, wait_nullwav ; wait for null wav address being initialised LD HL, (NULLWAVLEN) LD A, H OR L JP Z, wait_nullwav ; wait for null wav len being initialised stopChannel 0 ; stop all channels stopChannel 1 stopChannel 2 stopChannel 3 LD HL, WAVVOL ; init all channels to max volume LD A, $0F LD (HL), A INC L LD (HL), A INC L LD (HL), A INC L LD (HL), A LD A, STATREADY LD (STATUS), A ; driver ready main_loop ; channel 0 ; --------- ; $00 sampleOutput ; ' 30 | handlePlayCommand 0 ; ' 146 | 223 prepareVolume 0 ; ' 28 | wait19 ; ' 19 | ; $01 sampleOutput ; ' 30 | prepareChannel 0 ; ' 182 | 223 LD IXL, 9 ; prepare loop ' 11 | ; $02-$25 loop_ch0 readAndClear20WhilePlay3 ; ' 666 | wait4 ; ' 4 | sampleOutput ; ' 30 | readAndClear2 ; 26 samples per loop ' 56 | readAndClear2 ; ' 56 | 4*223 readAndClear2 ; ' 56 | wait6 ; DE modified here ' 6 | DEC IXL ; ' 8 | JP NZ, loop_ch0 ; ' 10 | ; $26-$29 readAndClear20WhilePlay3 ; ' 666 | wait4 ; ' 4 | sampleOutput ; ' 30 | 4*223 readAndClear2 ; process 22 samples ' 56 | updateChannelData 0 ; update channel data ' 76 | wait60 ; ' 60 | ; $2A sampleOutput ; ' 30 | checkChannelEnd 0 ; ' 180 | 223 wait13 ; ' 13 | ; channel 1 ; --------- ; $2B sampleOutput ; ' 30 | handlePlayCommand 1 ; ' 146 | 223 prepareVolume 1 ; ' 28 | wait19 ; ' 19 | ; $2C sampleOutput ; ' 30 | prepareChannel 1 ; ' 182 | 223 LD IXL, 21 ; prepare loop ' 11 | ; $2D-$6B loop_ch1 readAndMix12WhilePlay3 ; ' 640 | wait11 ; ' 11 | 3*223 DEC IXL ; 12 samples per loop ' 8 | JP NZ, loop_ch1 ; ' 10 | ; $6C sampleOutput ; ' 30 | readAndMix2 ; ' 90 | 223 readAndMix2 ; last 4 samples ' 90 | wait13 ; ' 13 | ; $6D sampleOutput ; ' 30 | updateChannelData 1 ; ' 76 | 223 wait117 ; ' 117 | ; $6E sampleOutput ; ' 30 | checkChannelEnd 1 ; ' 180 | 223 wait13 ; ' 13 | ; channel 2 ; --------- ; $6F sampleOutput ; ' 30 | handlePlayCommand 2 ; ' 146 | 223 prepareVolume 2 ; ' 28 | wait19 ; ' 19 | ; $70 sampleOutput ; ' 30 | prepareChannel 2 ; ' 182 | 223 LD IXL, 21 ; prepare loop ' 11 | ; $71-$AF loop_ch2 readAndMix12WhilePlay3 ; ' 640 | wait11 ; ' 11 | 3*223 DEC IXL ; 12 samples per loop ' 8 | JP NZ, loop_ch2 ; ' 10 | ; $B0 sampleOutput ; ' 30 | readAndMix2 ; ' 90 | 223 readAndMix2 ; last 4 samples ' 90 | wait13 ; ' 13 | ; $B1 sampleOutput ; ' 30 | updateChannelData 2 ; ' 76 | 223 wait117 ; ' 117 | ; $B2 sampleOutput ; ' 30 | checkChannelEnd 2 ; ' 180 | 223 wait13 ; ' 13 | ; channel 3 ; --------- ; $B3 sampleOutput ; ' 30 | handlePlayCommand 3 ; ' 146 | 223 prepareVolume 3 ; ' 28 | wait19 ; ' 19 | ; $B4 sampleOutput ; ' 30 | prepareChannel 3 ; ' 182 | 223 LD IXL, 21 ; prepare loop ' 11 | ; $B5-$F3 loop_ch3 readAndMix12WhilePlay3 ; ' 640 | wait11 ; ' 11 | 3*223 DEC IXL ; 12 samples per loop ' 8 | JP NZ, loop_ch3 ; ' 10 | ; $F4 sampleOutput ; ' 30 | readAndMix2 ; ' 90 | 223 readAndMix2 ; last 4 samples ' 90 | wait13 ; ' 13 | ; $F5 sampleOutput ; ' 30 | updateChannelData 3 ; ' 76 | 223 wait117 ; ' 117 | ; $F6 sampleOutput ; ' 30 | checkChannelEnd 3 ; ' 180 | 223 wait13 ; ' 13 | ; free time here ; -------------- ; $F7 sampleOutput ; ' 30 | LD IXL, 7 ; prepare loop ' 11 | wait182 ; ' 182 | ; $F8-FE loop_freetime sampleOutput ; ' 30 | wait175 ; ' 175 | 223 DEC IXL ; ' 8 | JP NZ, loop_freetime ; ' 10 | ; $FF sampleOutput ; ' 30 | swapBuffer ; swap buffers ' 72 | EXX ; ' 4 | LD BC, (READBUF) ; read buffer ' 20 | 223 EXX ; ' 4 | wait83 ; ' 83 | JP main_loop ; ' 10 | ; ############################## functions ################################ INCLUDE "z80_fct.i80" ; basic functions END