Chase H.Q.: Routine at F0C6

F0C6: White noise generator?

Used by the routine at define_keys.
noise	F0C6	LD E,A	E = A Outer-outer counter
noise_outer_loop	F0C7	LD D,$32	D = 50 Outer counter
noise_loop	F0C9	LD HL,$9618	Point at rng_seed / state bytes
	F0CC	INC (HL)	rng_seed[0] += 3 Increment first byte of seed by 3
	F0CD	INC (HL)
	F0CE	INC (HL)
	F0CF	LD B,(HL)	Load it into B
	F0D0	INC HL	HL++
	F0D1	LD A,(HL)	rng_seed[1] -= 141 Note that this is different order to rng/$961B
	F0D2	SUB $8D
	F0D4	LD (HL),A
	F0D5	ADD A,B	A = rng_seed[0] + rng_seed[1]
	F0D6	INC HL	HL++
	F0D7	RLCA	Rotate A by 1
	F0D8	RRC (HL)	Rotate rng_seed[2] by 1
	F0DA	ADD A,(HL)	A += *HL
	F0DB	LD (HL),A	*HL = A
	F0DC	AND $10	A &= 16
	F0DE	JR Z,noise_2	Jump to noise_2 if zero
	F0E0	LD A,$18	B = 24 - E
	F0E2	SUB E
	F0E3	LD B,A
noise_0	F0E4	DJNZ noise_0	Delay loop
	F0E6	LD A,$18	A = 24 EAR + MIC ?
	F0E8	OUT ($FE),A	Output
	F0EA	LD B,E	B = E
noise_1	F0EB	DJNZ noise_1	Delay loop
	F0ED	XOR A	A = 0
	F0EE	OUT ($FE),A	Output
noise_2	F0F0	DEC D	Decrement outer counter
	F0F1	JR NZ,noise_loop	Jump to noise_loop if non-zero
	F0F3	LD A,($EF14)	Read A from 'LD A' @ dk_wait -- spinlock/wait
	F0F6	AND A	Set flags
	F0F7	RET C	Return if carry set
	F0F8	DEC E	Decrement outer-outer counter
	F0F9	JR NZ,noise_outer_loop	Jump to noise_outer_loop if non-zero
	F0FB	JP dk_wait	Jump to dk_wait