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.MACRODEF LOAD_MUSIC =music_addr
LD A, bank(=music_addr)
LD ($mem_current_vgm_header), A
LD A, high(ptr(=music_addr))
LD ($mem_current_vgm_header+1), A
LD A, low(ptr(=music_addr))
LD ($mem_current_vgm_header+2), A
.END
Reset_Music_Channels:
CALL =Reset_Music_Channel4
CALL =Reset_Music_Channel3
CALL =Reset_Music_Channel2
Reset_Music_Channel1:
LD A, $00
LD ($11), A
LD ($12), A
LD ($13), A
LD ($14), A
RET
Reset_Music_Channel2:
LD A, $00
LD ($16), A
LD ($17), A
LD ($18), A
LD ($19), A
RET
Reset_Music_Channel3:
LD A, $00
LD ($1A), A
LD ($1B), A
LD ($1C), A
LD ($1D), A
LD ($1E), A
RET
Reset_Music_Channel4:
LD A, $00
LD ($20), A
LD ($21), A
LD ($22), A
LD ($23), A
RET
Start_Music:
LD A, ($mem_current_vgm_header)
.CHANGE_BANK_TO_A
LD A, ($mem_current_vgm_header+1)
LD H, A
LD A, ($mem_current_vgm_header+2)
LD L, A
LD A, L
ADD $34
LD L, A
LD A, H
ADC $00
LD H, A
CALL =Fix_HL_Bank
LD A, L
ADD (HL)
LD L, A
LD A, H
ADC $00
LD H, A
CALL =Fix_HL_Bank
LD A, $saved_rom_bank
LD ($mem_current_vgm_pc), A
LD A, H
LD ($mem_current_vgm_pc+1), A
LD A, L
LD ($mem_current_vgm_pc+2), A
RET
Loop_Music:
LD A, ($mem_current_vgm_header)
.CHANGE_BANK_TO_A
LD A, ($mem_current_vgm_header+1)
LD H, A
LD A, ($mem_current_vgm_header+2)
LD L, A
LD A, L
ADD $1c
LD L, A
LD A, H
ADC $00
LD H, A
CALL =Fix_HL_Bank
LD B, H
LD C, L
LD A, $saved_rom_bank
LD E, A
LD A, B
SUB $40
LD B, A
LD A, (HL)
CALL =Inc_HL_Fix_Bank
ADD C
LD C, A
LD A, (HL)
CALL =Inc_HL_Fix_Bank
ADC B
LD B, A
LD A, (HL)
CALL =Inc_HL_Fix_Bank
ADC E
LD E, A
LD A, $00
SLA B
RL A
ADD E
LD E, A
SRA B
LD A, $40
ADD B
LD B, A
LD A, E
LD ($mem_current_vgm_pc), A
LD A, B
LD ($mem_current_vgm_pc+1), A
LD A, C
LD ($mem_current_vgm_pc+2), A
RET
Inc_HL_Fix_Bank:
PUSH AF
INC HL
CALL =Fix_HL_Bank
POP AF
RET
Fix_HL_Bank:
LD A, H
CP $80
JR C, =.end
SUB $40
LD H, A
LD A, $saved_rom_bank
INC A
.CHANGE_BANK_TO_A
.end:
RET
Check_Channel_Available:
; TODO: Channel panning register in $FF25 is still impacted by music
CP $24
RET NC
PUSH BC
CP $1A
JR NC =.channel_3_4
.channel_1_2:
CP $16
JR NC, =.channel_2
.channel_1:
LD C, A
LD A, $mem_sound_flags
BIT 1, A
LD A, C
JR Z, =.end
LD A, $00
JR =.end
.channel_2:
LD C, A
LD A, $mem_sound_flags
BIT 2, A
LD A, C
JR Z, =.end
LD A, $00
JR =.end
.channel_3_4:
CP $20
JR NC, =.channel_4
.channel_3:
LD C, A
LD A, $mem_sound_flags
BIT 3, A
LD A, C
JR Z, =.end
LD A, $00
JR =.end
.channel_4:
LD C, A
LD A, $mem_sound_flags
BIT 4, A
LD A, C
JR Z, =.end
LD A, $00
.end:
POP BC
RET
Play_Music:
LD A, $mem_sound_flags
BIT 0, A
RET Z
BIT 5, A
JR Z, =.sound_effect_frame_count_dec_skip
LD A, $mem_sound_effect_frame_count
DEC A
LD $mem_sound_effect_frame_count, A
CP $00
JR NZ, =.sound_effect_frame_count_dec_skip
LD A, $mem_sound_flags
AND 0b11000001
LD $mem_sound_flags, A
.sound_effect_frame_count_dec_skip:
LD A, ($mem_current_vgm_pc)
.CHANGE_BANK_TO_A
LD A, ($mem_current_vgm_pc+1)
LD H, A
LD A, ($mem_current_vgm_pc+2)
LD L, A
.next:
LD A, (HL)
CALL =Inc_HL_Fix_Bank
CP $b3
JR NZ, =.set_register.end
.set_register:
LD A, (HL)
CALL =Inc_HL_Fix_Bank
LD C, A
LD B, (HL)
CALL =Inc_HL_Fix_Bank
LD A, C
ADD $10
CALL =Check_Channel_Available
CP $00
JR Z, =.next
LD C, A
LD A, B
LD (C), A
JR =.next
.set_register.end:
CP $66
JP Z, =Loop_Music
CP $62
JR Z, =.panic.end
CP $61
JR NZ, =.the61thingy.end
.the61thingy:
CALL =Inc_HL_Fix_Bank
CALL =Inc_HL_Fix_Bank
JR =.panic.end
.the61thingy.end:
.panic:
LD A, $saved_rom_bank
STOP
.panic.end:
LD A, H
LD ($mem_current_vgm_pc+1), A
LD A, L
LD ($mem_current_vgm_pc+2), A
LD A, $saved_rom_bank
LD ($mem_current_vgm_pc), A
RET
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