[destination] ← 0
CLR <ea>CLR (A4)+Size byte, word, longword
The destination is cleared - loaded with all zeros. The CLR instruction can't be used to clear an address register. You can use SUBA.L A0,A0 to clear A0. Note that a side effect of CLR's implementation is a read from the specified effective address before the clear (i.e., write) operation is executed. Under certain circumstances this might cause a problem (e.g., with write-only memory).
| X | N | Z | V | C |
|---|---|---|---|---|
| - | 0 | 1 | 0 | 0 |
| Dn | An | (An) | (An)+ | ‑(An) | (d,An) | (d,An,Xi) | ABS.W | ABS.L | (d,PC) | (d,PC,Xn) | imm |
|---|---|---|---|---|---|---|---|---|---|---|---|
| ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
From MOTOROLA M68000 FAMILY Programmer's reference manual. Copyright 1992 by Motorola Inc./NXP. Adapted with permission.