Difference between revisions of "SWAP"
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<tr><td>Output Flags</td><td>[[Sign Flag]], [[Zero Flag]]</td></tr> | <tr><td>Output Flags</td><td>[[Sign Flag]], [[Zero Flag]]</td></tr> | ||
</table><br/> | </table><br/> | ||
| − | The Swap Bytes (SWAP) instruction can perform two very different functions depending on the "double swap" indicator. A single swap trades the lowest eight bits in a register with the upper eight bits. A double swap essentially copies the lowest eight bits in a register to the upper eight bits. Regardless of which swap is specified, the CP1610 then sets or clears the [[Sign Flag]] and [[Zero Flag] according to the resulting value. The opcode format is as follows.<br/> | + | The Swap Bytes (SWAP) instruction can perform two very different functions depending on the "double swap" indicator. A single swap trades the lowest eight bits in a register with the upper eight bits. A double swap essentially copies the lowest eight bits in a register to the upper eight bits. Regardless of which swap is specified, the CP1610 then sets or clears the [[Sign Flag]] and [[Zero Flag] according to the resulting value. The number of clock cycles used depends on the type of swap specified. A single swap will use 6 clock cycles and a double swap will use 8 clock cycles. The opcode format is as follows.<br/> |
0000:0000:0100:1srr<br/> | 0000:0000:0100:1srr<br/> | ||
Revision as of 20:13, 14 January 2005
| Instruction Name | Swap Bytes |
| Mnemonic | SWAP |
| CP1610 Clock Cycles | 6 or 8 |
| Interruptible | No |
| Opcode Range | $0040-$0047 |
| Input Flags | None |
| Output Flags | Sign Flag, Zero Flag |
The Swap Bytes (SWAP) instruction can perform two very different functions depending on the "double swap" indicator. A single swap trades the lowest eight bits in a register with the upper eight bits. A double swap essentially copies the lowest eight bits in a register to the upper eight bits. Regardless of which swap is specified, the CP1610 then sets or clears the Sign Flag and [[Zero Flag] according to the resulting value. The number of clock cycles used depends on the type of swap specified. A single swap will use 6 clock cycles and a double swap will use 8 clock cycles. The opcode format is as follows.
0000:0000:0100:1srr
where: s indicates the type of swap such that: s == 0 indicates a single swap s == 1 indicates a double swap
rr indicates the target register such that: rr == 00 indicates register R0 rr == 01 indicates register R1 rr == 10 indicates register R2 rr == 11 indicates register R3
