For example, with M[$42]=$80 and M[$43]=$10 and Y=$F1, the instruction LDA ($42),Y will execute as follow:
*T0: Fetch opcode $B1 (LDA (zp),Y) from memorythen increment PC*T1: Fetch operand byte $42 (zero page pointer address)then increment PC
*T2: Get low byte from zero page ($80)
*T3: Get high byte from next zero page location ($10) in the first half-cycle, then add the Y-register value ($F1) to $1080
*T4: Handle page boundary crossing (since $1080 + $F1 crosses a page)
*T5: Read the value from memory address $1171 into the accumulator