Routines
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F9AF: Play Queued Sound
Used by the routines at GameStart, Update_Berk_State, Handle_Berk_Action, Print_EncodedMessage and Clear_AttributeFile.
Play the sound queued at PendingSoundIndex using the parameter block selected from base F907 (sound 01 starts at Table_SoundParameters), then clear the queue. The base F907 is the operand byte of JR NZ in Queue_Sound; it is never read as a parameter because indexes start at 01.
Fetch the pending sound and return if the queue is empty.
Play_QueuedSound F9AF LD A,($7309) Fetch the pending sound index from PendingSoundIndex.
F9B2 AND %01111111 Keep only bits 00–06 (mask 7F).
F9B4 RET Z Return if the queue was empty.
F9B5 PUSH IX Stash IX on the stack.
Point IX at this sound's parameter block and clear the queue.
F9B7 ADD A,A Multiply the index by 08.
F9B8 ADD A,A
F9B9 ADD A,A
F9BA LD C,A Keep the table offset in C.
F9BB XOR A Clear PendingSoundIndex.
F9BC LD ($7309),A
F9BF LD B,A Clear B (high byte of the offset).
F9C0 LD IX,$F907 Point IX at F907 (operand of F906) plus the offset.
F9C4 ADD IX,BC
Load the tone parameters and play.
F9C6 LD C,(IX+$00) Load the outer repeat count from IX+00 into C.
Outer repeat: reload pulse count and on/off delays from the parameter block.
Play_QueuedSound_RepeatLoop F9C9 LD B,(IX+$01) Load the pulse count from IX+01 into B.
F9CC LD E,(IX+$02) Load the speaker-off delay from IX+02 into E.
F9CF LD D,(IX+$03) Load the speaker-on delay from IX+03 into D.
F9D2 LD H,(IX+$06) Load the flags / waveform high byte from IX+06 into H.
One speaker pulse: turn EAR on, delay, optional waveform, then EAR off.
Play_QueuedSound_PulseLoop F9D5 PUSH BC Stash BC on the stack.
F9D6 LD A,($EA6C) Fetch the border / speaker state from BorderSpeakerState.
F9D9 SET 4,A Set bit 04 (speaker on).
F9DB OUT ($FE),A Send it to the speaker (port FE).
F9DD LD B,D Keep the on-delay in B.
Hold the speaker on for the on-delay in D.
Play_QueuedSound_OnDelay F9DE NOP Hold for the on-delay. jump to Play_QueuedSound_OnDelay while it remains.
F9DF DJNZ Play_QueuedSound_OnDelay
F9E1 BIT 7,H Is the square-wave-only flag set? If so, jump to Play_QueuedSound_SpeakerOff.
F9E3 JR NZ,Play_QueuedSound_SpeakerOff
F9E5 LD B,(HL) Fetch the next waveform delay into B.
F9E6 INC HL Advance the waveform pointer in HL.
Pad the non-square waveform delay from the stream at HL.
Play_QueuedSound_WaveDelay F9E7 BIT 0,(IX+$00) Timing pad for the waveform delay.
F9EB NOP
F9EC NOP
F9ED NOP
F9EE NOP
F9EF NOP
F9F0 NOP
F9F1 DJNZ Play_QueuedSound_WaveDelay Decrease the waveform delay and jump to Play_QueuedSound_WaveDelay while it remains.
Turn the speaker off and hold for the off-delay in E.
Play_QueuedSound_SpeakerOff F9F3 RES 4,A Clear bit 04 (speaker off).
F9F5 OUT ($FE),A Send it to the speaker (port FE).
F9F7 LD B,E Keep the off-delay in B.
Hold the speaker off for the off-delay, then apply the per-pulse deltas.
Play_QueuedSound_OffDelay F9F8 NOP Hold for the off-delay. jump to Play_QueuedSound_OffDelay while it remains.
F9F9 DJNZ Play_QueuedSound_OffDelay
F9FB LD A,(IX+$04) Add the on-delay delta from IX+04 to D.
F9FE ADD A,D
F9FF LD D,A
FA00 LD A,(IX+$05) Add the off-delay delta from IX+05 to E.
FA03 ADD A,E
FA04 LD E,A
FA05 POP BC Restore BC from the stack.
FA06 DJNZ Play_QueuedSound_PulseLoop Decrease the pulse counter and jump to Play_QueuedSound_PulseLoop while pulses remain.
FA08 DEC C Decrease the repeat counter.
FA09 JR NZ,Play_QueuedSound_RepeatLoop Jump to Play_QueuedSound_RepeatLoop while repeats remain.
Housekeeping; restore the registers stashed at the start of the routine.
FA0B POP IX Restore IX from the stack.
FA0D RET Return.
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