Routines
Prev: 6AAD Up: Map Next: 6AD7
6AC4: Action: Beep
Used by the routine at WaitForKey.
Turns A and B into a duration and a pitch and hands them to the ROM beeper. The key click uses A equal to 1E. Action 0 of the bytecode jumps straight to the same ROM routine, whose address is the operand of the jump below.
Beep 6AC4 AND A Duration A is the low byte of HL, and B is the pitch.
6AC5 LD L,A
6AC6 LD A,B
6AC7 LD D,$00 The high byte of the duration, and D, start at zero.
6AC9 LD H,D
6ACA ADD A,A Shift the pitch two places, keeping the overflow in D.
6ACB ADD A,A
6ACC RL D
6ACE LD E,A Save that pitch.
6ACF PUSH DE
6AD0 CALL $30A9 Call HL=HL*DE to scale the duration by the pitch.
6AD3 POP DE Restore the pitch for the beeper from the stack.
6AD4 JP $03B5 Jump to BEEPER.
Prev: 6AAD Up: Map Next: 6AD7