Compares the value of the memory location pointed to by HL with A. Then HL and BC are decremented. If BC is not zero and z is not set, this operation is repeated. p/v is reset if BC becomes zero and set otherwise, acting as an indicator that HL reached a memory location whose value equalled A before the counter went to zero. Interrupts can trigger while this instruction is processing.
cpdr
Operands
cpdrLoading...
Variants
Every form of cpdr the assembler accepts. The cycles column counts clock
cycles, written as taken/not taken for the conditional forms.
| Instruction | Description | Flags | Bytes | Cycles |
|---|---|---|---|---|
| cpdr | Compares the value of the memory location pointed to by HL with A. Then HL and BC are decremented. If BC is not zero and z is not set, this operation is repeated. p/v is reset if BC becomes zero and set otherwise, acting as an indicator that HL reached a memory location whose value equalled A before the counter went to zero. Interrupts can trigger while this instruction is processing. | N=1P/V=*HZS | 2 | 21/16 |