BIOS Sound Functions
More actions
Output to Sound Queue
BCAA SOUND_QUEUE (output sound) ;in: HL=data ;ch,env,ent,freq(lo,hi,noise),vol,len(lo,hi)
In: HL=Pointer to 9-byte Data Block
0 Channel (Bit0-2=ChannelA-C, Bit3-5=RendevousA..C, Bit6=Hold, Bit7=Flush) 1 ENV Volume Envelope (1..15, or 0=none) 2 ENT Tone Envelope (1..15, or 0=none) 3 Tone Frequency, lower 8bit (000h=none) 4 Tone Frequency, upper 4bit 5 Noise Frequency (01h..1Fh, or 00h=none) ;shared for all 3 channels 6 Volume (00h..0Fh) 7 Duration, lower 8bit (in 1/100 seconds) ;\0=endless/until end of ENV? 8 Duration, upper 8bit ;/negative=repeat ENV -N times?
Out: CY=1=okay, CY=0=Queue Full. Equivalent to BASIC's "SOUND".
Set Volume Envelope
BCBC SOUND_SET_ENV
In: A=Envelope number (1..15), HL=Pointer to Data (must be >3FFFh) The data block starts with a header byte:
bit7 envelope type (0=software, 1=hardware) bit6-0 number of following 3-byte parameters (1..5)
The following 3-byte parameters can be (when Byte 0, Bit7=0):
Byte 0 Number of steps (01h..7Fh) Byte 1 Step (-80h..+7Fh) (of which, only -0Fh..+0Fh makes sense) Byte 2 Duration per step (in 1/100 seconds) (01h..FFh, or 00h=100h)
Or, using the (less comfortable) hardware envelope (when Byte 0, Bit7=1):
Byte 0 PSG Envelope Shape (00h..0Fh), plus 80h ;PSG Register 0Dh Byte 1 PSG Envelope Frequency, upper 8bit ;PSG Register 0Ch Byte 2 PSG Envelope Frequency, lower 8bit ;PSG Register 0Bh
Equivalent to BASIC's "ENV". The initial sound volume is SOUND_QUEUE's [HL+6]. Note that the step is added to the sound volume (there's NO separate envelope volume register, multiplied with the sound volume). Take care that the volume doesn't overflow/underflow.
Set Tone Envelope
BCBF SOUND_SET_ENT
In: A=Envelope number (1..15), HL=Pointer to Data (must be >3FFFh) The data block starts with a header byte:
bit7 envelope type (0=software, 1=hardware) bit6 repeat flag (0=one shot, 1=repeat envelope) bit5-0 number of following 3-byte parameters (1..5)
The following 3-byte parameters can be (when Byte 0 is <F0h):
Byte 0 Number of steps (01h..EFh) Byte 1 Step (-80h..+7Fh) Byte 2 Duration per step (in 1/100 seconds) (01h..FFh, or 00h=100h)
Or, setting the frequency directly, non-relative (when Byte 0 is >=F0h):
Byte 0 Upper 4bit of frequency, plus F0h ;PSG Register 01h,03h,05h Byte 1 Lower 8bit of frequency ;PSG Register 00h,02h,04h Byte 2 Duration (in 1/100 seconds) (01h..FFh, or 00h=100h)
Equivalent to BASIC's "ENT".
Sound Reset
BCA7 SOUND_RESET
Reset and mute sound output.
Sound Check
BCAD SOUND_CHECK
In: A=channel mask, Out: A=channel status.
Sound Event
BCB0 SOUND_ARM_EVENT
In: A=channel mask, HL=event block. Equivalent to BASIC's "ON SQ GOSUB". Triggers when the channels queue is not full?
Sound Release
BCB3 SOUND_RELEASE
In: A=channel mask. Starts pending sounds (which did have the "Hold" bit set; ie. Bit6 of Byte0 passed to SOUND_QUEUE). Equivalent to BASIC's "RELEASE".
Sound Pause/Unpause
BCB6 SOUND_PAUSE ;Out: CY=1=okay, CY=0=nothing to do. BCB9 SOUND_UNPAUSE
Freezes/unfreezes sound output.
Get Envelope
BCC2 SOUND_GET_ENV BCC5 SOUND_GET_ENT
In: A=Envelope number (01h..0Fh), Out: HL=16-byte block, CY=1=okay.
Machine Pack
BD34 MC_SOUND_REGISTER ;in: A=PSG index, C=PSG data
Directly writes to a PSG register (this would conflict with the other SOUND functions).