diff options
Diffstat (limited to 'src-z80/player')
| -rw-r--r-- | src-z80/player/pcm.z80 | 169 |
1 files changed, 135 insertions, 34 deletions
diff --git a/src-z80/player/pcm.z80 b/src-z80/player/pcm.z80 index 71b0d72..18527d9 100644 --- a/src-z80/player/pcm.z80 +++ b/src-z80/player/pcm.z80 @@ -19,10 +19,9 @@ PlayPCMBGM: PlayPCM: call GetParam ; Get sample ID - + ld a, b exx ; We'll modify PCM data now - ld b, $01 ; Play PCM! ld h, RAM_PointerList>>8 ; Get offset in pointer list ld l, a @@ -32,10 +31,38 @@ PlayPCM: ld e, (hl) inc h ld c, (hl) + + ld hl, $6000 ; Initial bank switch + ld a, c + ld (RAM_LastBank), a + BankSwitch + + ld h, RAM_PCMBuffer>>8 ; Set buffer where the sample starts + ld a, e + or $F0 + ld l, a + + ld b, l +.load1st: ; Copy initial samples into the buffer + ld a, (de) + ld (hl), a + inc e + inc l + jp nz, .load1st + ld l, b + + ld a, e ; Check if the sample should skip ahead + or a ; already + jp nz, .noskip1st + inc d + jp nz, .noskip1st + ld d, $80 + inc c +.noskip1st: - ld hl, $6000 ; Restore $6000 back to HL - exx ; Back to standard variables - + ld b, $01 ; Play PCM! + exx ; Back to standard registers + ld (ix+0), $2B ; Turn on DAC ld (ix+1), $80 ld (ix+0), $2A @@ -49,43 +76,27 @@ PlayPCM: ;**************************************************************************** UpdatePCM: - ;ld (ix+0), $24 ; Reset timer - ;ld (ix+1), $FE - ;ld (ix+0), $25 - ;ld (ix+1), $03 - - ld (ix+0), $27 - ld (ix+1), $1F - exx ; Switch to PCM registers ld a, b ; Do any playback? or a jr z, .nopcm + +.doagain: + ld (ix+0), $27 ; Acknowledge timer + ld (ix+1), $1F - ld a, (RAM_LastBank) ; Bank switch? - cp c - jp z, .noswitchu - ld a, c - ld (RAM_LastBank), a - BankSwitch -.noswitchu: - - ld a, (de) ; Get sample - inc a ; Is it end of waveform? - jr z, .stop ; If so, stop + ld a, (hl) ; Fetch next sample + inc a ; Check if it's the end of the waveform + jr z, .stop ld (ix+0), $2A ; Nope, send sample to YM2612 ld (ix+1), a - - inc e ; Get address for next sample - jr nz, .nopcm - inc d - jr nz, .nopcm - ld d, $80 - inc c + + inc l ; Update buffer position + jr z, .reload ; Need to buffer more? .nopcm: - exx ; Go back to normal registers + exx ; Switch to normal registers ret ; End of subroutine .stop: @@ -94,9 +105,100 @@ UpdatePCM: ld (ix+1), $80 ld (ix+0), $2B ld (ix+1), $00 - exx ; Go back to normal registers + exx ; Switch to normal registers ret ; End of subroutine +.reload: + ld a, (RAM_LastBank) ; Bank switch if needed + cp c + jp z, .noswitchu + ld a, c + ld (RAM_LastBank), a + ld hl, $6000 + BankSwitch +.noswitchu: + + ld hl, RAM_PCMBuffer ; Load samples into the buffer + + ld a, (de) ; Samples 1~4 + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + + ld a, (de) ; Samples 5~8 + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + + ld a, (de) ; Samples 9~12 + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + + ld a, (de) ; Samples 13~16 + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + ld a, (de) + ld (hl), a + inc l + inc e + + jp nz, .nobankchg ; Update high bytes of address if needed + inc d + jp nz, .nobankchg + ld d, $80 + inc c +.nobankchg: + + ld l, RAM_PCMBuffer&$FF ; Go back to the beginning of the buffer + jp .doagain ; We took so long we should play the next + ; sample already ._.' + ;**************************************************************************** ; StopPCM* ; Stops a PCM sample @@ -126,7 +228,6 @@ StopPCM: ret ; End of subroutine - ;**************************************************************************** ; LockChannelPCM [event $EC] ; Locks the PCM channel |