Krakout: Sound effect: tape-load error

B873: Sound effect: tape-load error

The failure signal for a LOAD LEVELS tape load, played ten times over when the ROM loader reports failure.
sfx_load_error	B873	PUSH DE	Preserve the caller's BC and DE.
	B874	PUSH BC	Preserve the caller's BC and DE.
	B875	LD D,$C8	Set the first period, then reuse that same byte as the cycle count.
	B877	LD C,D
sfx_load_error_cycle	B878	CALL sound_blip	Emit one square-wave cycle at the current period.
	B87B	RLC D	Rotate the period left one bit each cycle, so it walks eight values in turn.
	B87D	DEC C
	B87E	JR NZ,sfx_load_error_cycle
	B880	POP BC
	B881	POP DE
	B882	RET

Routines