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BGM Header format
00: b Number of channels (always must be 09h = 6 FM + 3 PSG) 01: b Volume (99 = max, 0 = min) 02: b Tempo modifier 03: b Pitch modifier 04: w Volume table pointer 06: w Channel tracks table pointer 08: w Patterns table pointer 0A: w FM Voices bank pointer 0C: w PSG Voices bank pointer 0E: w End of file offset Credits goes to vladikcomper for the info on this. Thanks! Sharp X68000 Version 00: w ? 02: w Pointer to instrument ? 04: w ? 06: w ? Research is still in progress!
Volume Controll for each channel
10: Channel Volume Channel tracks table stores offset for all 9 sound channels used by driver in the following order: FM1, FM2, FM3, FM4, FM5, FM6, PSG1, PSG2, PSG3 Channel tracks cannot be skipped -- if the channel is unused, corresponding track should start with byte 0FFh (end of track marker). Each FM/PSG track refers to patterns from patterns table by table entry number. Both tracks and patterns can execute coordinate flags. 10: Volume for channel 1 11: Volume for channel 2 12: Volume for channel 3 13: Volume for channel 4 14: Volume for channel 5 15: Volume for channel 6 16: Volume for PSG 1 17: Volume for PSG 2 18: Volume for PSG 3 Sharp X68000 Version D2: Channel Volume Channel tracks table stores offset for all 9 sound channels used by driver in the following order: channel 1, channel 2, channel 3, channel 4, channel 5, channel 6, channel 7, channel 8, channel 9 channel 10, channel 11, channel 12, channel 13, channel 14, channel 15, channel 16 Channel tracks cannot be skipped -- if the channel is unused, corresponding track should start with byte 0FFh (end of track marker). Each FM/PSG track refers to patterns from patterns table by table entry number. Both tracks and patterns can execute coordinate flags. D2: Volume for channel 1 D3: Volume for channel 2 D4: Volume for channel 3 D5: Volume for channel 4 D6: Volume for channel 5 D7: Volume for channel 6 D8: Volume for channel 7 D9: Volume for channel 8 DA: Volume for channel 9 DB: Volume for channel 10 DC: Volume for channel 11 DD: Volume for channel 12 DE: Volume for channel 13 DF: Volume for channel 14 E0: Volume for channel 15 E1: Volume for channel 16
Channel Tracks Table
19: Pointer to channel 1 1B: Pointer to channel 2 1D: Pointer to channel 3 1F: Pointer to channel 4 21: Pointer to channel 5 23: Pointer to channel 6 25: Pointer to PSG 1 27: Pointer to PSG 2 Sharp X68000 Version The Channel Track Pointer starts at $01D2 $01D2: w ? $01D4: w Pointer to channel
$80-$DF Notes - Same as the Sharp X68000 Version. $E0-$FF Coordination flags - Same As the Sharp X68000 Version but it might be different.
Music Notes Value
Same as the Sharp X68000 Version. C-1: 80 C#1: 81 D-1: 82 D#1: 83 E-1: 84 F-1: 85 F#1: 86 G-1: 87 G#1: 88 A-1: 89 A#1: 8A B-1: 8B C-2: 8C C#2: 8D D-2: 8E D#2: 8F E-2: 90 F-2: 91 F#2: 92 G-2: 93 G#2: 94 A-2: 95 A#2: 96 B-2: 97 C-3: 98 C#3: 99 D-3: 9A D#3: 9B E-3: 9C F-3: 9D F#3: 9E G-3: 9F G#3: A0 A-3: A1 A#3: A2 B-3: A3 C-4: A4 C#4: A5 D-4: A6 D#4: A7 E-4: A8 F-4: A9 F#4: AA G-4: AB G#4: AC A-4: AD A#4: AE B-4: AF C-5: B0 C#5: B1 D-5: B2 D#5: B3 E-5: B4 F-5: B5 F#5: B6 G-5: B7 G#5: B8 A-5: B9 A#5: BA B-5: BB C-6: BC C#6: BD D-6: BE D#6: BF E-6: C0 F-6: C1 F#6: C2 G-6: C3 G#6: C4 A-6: C5 A#6: C6 B-6: C7 C-7: C8 C#7: C9 D-7: CA D#7: CB E-7: CC F-7: CD F#7: CE G-7: CF G#7: D0 A-7: D1 A#7: D2 B-7: D3 C-8: D4 C#8: D5 D-8: D6 D#8: D7 E-8: D8 F-8: D9 F#8: DA G-8: DB G#8: DC A-8: DD A#8: DE B-8: DF
Might be the same as the Sharp X68000 Version. E0 - LoadInstrument E1 - SetPan E2 - PSGEffect E3 - SetSlideSpeed E4 - AMS_FMS_Speed E5 - SkipPatterns_or_Sync E6 - SetArgument E7 - AlterArgument E8 - AlterNote E9 - AlterVolume EA - AlterTempo EB - SetFreqDisplacement EC - SetRepeat ED - SetFadeSpeed F0 - DisableAMS_FMS F1 - EnableAMS_FMS F2 - DisablePSGNoise F3 - EnablePSGNoise F4 - SetPortamentoMode0 F5 - SetPortamentoMode1 F6 - SetPortamentoMode2 F7 - SetPortamentoMode3 FD - repeat_pattern Credits goes to vladikcomper for the info on this. Thanks!