Chase H.Q.: Routine at F7FF

F7FF: Setup the next music pattern

Almost the same as EE6E
Keep playing current pattern until this counter becomes zero.
bank7_next_pattern	F7FF	LD A,$00	Load number of pattern repetitions. Self modified by F80F below.
	F801	DEC A	Decrease
	F802	LD ($F311),A	Self modify bank7_next_pattern above
	F805	RET NZ	Return if non-zero
b7np_next	F806	LD HL,$0000	Load address of current pattern. Self modified by F814 below.
b7np_start_at_hl	F809	LD A,(HL)	Read new repetition count
	F80A	INC HL	Read new repetition count
	F80B	CP $FF	Jump to b7np_restart if it's $FF (end of patterns)
	F80D	JR Z,b7np_restart	Jump to b7np_restart if it's $FF (end of patterns)
	F80F	LD ($F311),A	Self modify bank7_next_pattern above with new repetition count
	F812	LD C,(HL)	Read music data offset
	F813	INC HL	Read music data offset
	F814	LD ($F318),HL	Self modify b7np_next above (pattern addr)
Calculate address of music data.
	F817	LD B,$00	BC = C
	F819	LD HL,$F553	Load address of base of music data
	F81C	ADD HL,BC	Combine with offset
	F81D	LD A,(HL)	A = *HL++ -- load first byte of music data
	F81E	INC HL	A = *HL++ -- load first byte of music data
	F81F	LD ($F362),A	Self modify b7pm_delay_complete (delay reload, first byte of pattern)
	F822	LD ($F356),A	Self modify b7pm_delay_1 (delay counter, first byte of pattern)
	F825	LD ($F372),HL	Self modify b7pm_reset_pattern (addr of second music data byte in pattern)
	F828	RET	Return
b7np_restart	F829	LD A,(HL)	HL = wordat(HL); HL++
	F82A	INC HL
	F82B	LD H,(HL)
	F82C	LD L,A
	F82D	JR b7np_start_at_hl	Jump to b7np_start_at_hl