diff options
Diffstat (limited to 'src-z80/player/pcm.z80')
| -rw-r--r-- | src-z80/player/pcm.z80 | 197 |
1 files changed, 101 insertions, 96 deletions
diff --git a/src-z80/player/pcm.z80 b/src-z80/player/pcm.z80 index 99feb6d..2b7bcc4 100644 --- a/src-z80/player/pcm.z80 +++ b/src-z80/player/pcm.z80 @@ -1,100 +1,21 @@ ;**************************************************************************** -; PlayPCM* [event $0C] -; Plays a PCM sample -;---------------------------------------------------------------------------- -; input c .... current bank -; input hl ... current address -;---------------------------------------------------------------------------- -; breaks: af, b -;**************************************************************************** - -PlayPCMSFX: - call PlayPCM ; We're just a wrapper - jp ProcessSFXRun ; End of subroutine - -PlayPCMBGM: - PollPCM - - ld a, (RAM_Locked+6) ; Check if channel is free - or a - jp nz, ProcessBGMSkip1 ; Don't play sample if locked - - call PlayPCM ; We're just a wrapper - jp ProcessBGMRun ; End of subroutine - -PlayPCM: - ld a, (RAM_GlobalVol+$0C) ; Are we allowed to play PCM? - or a - ret z - - call GetParam ; Get sample ID - - ld a, b - exx ; We'll modify PCM data now - - ld h, RAM_PointerList>>8 ; Get offset in pointer list - ld l, a - - ld d, (hl) ; Get PCM address - inc h - 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 b, $01 ; Play PCM! - exx ; Back to standard registers - xor a ; Enable PCM playback - ld (UpdatePCM), a - - ld (ix+0), $2B ; Turn on DAC - ld (ix+1), $80 - ld (ix+0), $2A - ld (ix+1), $80 - - ret ; End of subroutine - -;**************************************************************************** ; UpdatePCM ; Updates PCM output upon a timer event ;**************************************************************************** UpdatePCM: - ret ; RET = no PCM playback - ; NOP = PCM playback + ret ; $C9 = RET = no PCM playback + ; $D0 = RET NC = PCM playback exx ; Switch to PCM registers .doagain: ld (ix+0), $27 ; Acknowledge timer ld (ix+1), $1F + ;push hl + ;ld hl, $1F27 + ;ld ($4000), hl + ;pop hl ld a, (hl) ; Fetch next sample inc a ; Check if it's the end of the waveform @@ -110,7 +31,9 @@ UpdatePCM: ret ; End of subroutine .stop: - ld b, $00 ; Stop playback +; ld b, $00 ; Stop playback + ld a, $C9 ; Stop playback + ld (UpdatePCM), a ld (ix+0), $2A ; Turn off DAC ld (ix+1), $80 ld (ix+0), $2B @@ -210,6 +133,88 @@ UpdatePCM: ; sample already ._.' ;**************************************************************************** +; PlayPCM* [event $0C] +; Plays a PCM sample +;---------------------------------------------------------------------------- +; input c .... current bank +; input hl ... current address +;---------------------------------------------------------------------------- +; breaks: af, b +;**************************************************************************** + +PlayPCMSFX: + call PlayPCM ; We're just a wrapper + jp ProcessSFXRun ; End of subroutine + +PlayPCMBGM: + PollPCM + + ld a, (RAM_Locked+6) ; Check if channel is free + or a + jp nz, ProcessBGMSkip1 ; Don't play sample if locked + + call PlayPCM ; We're just a wrapper + jp ProcessBGMRun ; End of subroutine + +PlayPCM: + ld a, (RAM_GlobalVol+$0C) ; Are we allowed to play PCM? + or a + ret z + + call GetParam ; Get sample ID + + ld a, b + exx ; We'll modify PCM data now + + ld h, RAM_PointerList>>8 ; Get offset in pointer list + ld l, a + + ld d, (hl) ; Get PCM address + inc h + 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: + + exx ; Back to standard registers + ld a, $D0 ; Enable PCM playback + ld (UpdatePCM), a + + ld (ix+0), $2B ; Turn on DAC + ld (ix+1), $80 + ld (ix+0), $2A + ld (ix+1), $80 + + ret ; End of subroutine + +;**************************************************************************** ; StopPCM* ; Stops a PCM sample ;**************************************************************************** @@ -257,21 +262,21 @@ LockChannelPCM: SetPCMRate: ld a, (RAM_ComBank) ; Get new rate cpl - ld b, a - xor a ; Parsed command already - ld (RAM_Command), a - - ld a, b ; Set high bits of timer - ld (ix+0), $24 + ld b, a ; Set high bits of timer + ld hl, $4000 + ld (hl), $24 rrca rrca or $C0 - ld (ix+1), a + inc l + ld (hl), a ld a, b ; Set low bits of timer - ld (ix+0), $25 + dec l + ld (hl), $25 and $03 - ld (ix+1), a + inc l + ld (hl), a - jp IdleLoop ; End of subroutine + jp EndOfCommand ; End of subroutine |