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| <head> |
| <title>move-wide</title> |
| <link rel=stylesheet href="opcode.css"> |
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| <body> |
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| <h1>move-wide</h1> |
| |
| <h2>Purpose</h2> |
| |
| <p> |
| Move the contents of one register-pair to another. |
| </p> |
| <p> |
| Note: It is legal to move from vN to either vN-1 or vN+1, so implementations |
| must arrange for both halves of a register pair to be read before anything is |
| written. |
| </p> |
| |
| <h2>Details</h2> |
| |
| <table class="instruc"> |
| <thead> |
| <tr> |
| <th>Op & Format</th> |
| <th>Mnemonic / Syntax</th> |
| <th>Arguments</th> |
| </tr> |
| </thead> |
| <tbody> |
| <tr> |
| <td>04 12x</td> |
| <td>move-wide vA, vB</td> |
| <td><code>A:</code> destination register pair (4 bits)<br/> |
| <code>B:</code> source register pair (4 bits)</td> |
| </tr> |
| <tr> |
| <td>05 22x</td> |
| <td>move-wide/from16 vAA, vBBBB</td> |
| <td><code>A:</code> destination register pair (8 bits)<br/> |
| <code>B:</code> source register pair (16 bits)</td> |
| </tr> |
| <tr> |
| <td>06 32x</td> |
| <td>move-wide/16 vAAAA, vBBBB</td> |
| <td><code>A:</code> destination register pair (16 bits)<br/> |
| <code>B:</code> source register pair (16 bits)</td> |
| </tr> |
| </tbody> |
| </table> |
| |
| <h2>Constraints</h2> |
| |
| <ul> |
| <li> |
| Both A+1 and B+1 must be valid register indices in the current stackframe |
| (which includes A and B being valid). |
| </li> |
| <li> |
| Register vB must be the lower half of a register pair (which excludes the |
| case of it containing a reference). |
| </li> |
| <li> |
| Both register vB and v(B+1) must be defined. |
| </li> |
| </ul> |
| |
| <h2>Behavior</h2> |
| |
| <ul> |
| <li> |
| The value of register vB is moved to register vA, that is, vA' = vB. |
| </li> |
| <li> |
| The value of register v(B+1) is moved to register v(A+1), that is, v(A+1)' |
| = v(B+1). |
| </li> |
| <li> |
| If register v(A-1) is the lower half of a register pair, then v(A-1)' |
| becomes undefined. |
| </li> |
| <li> |
| If register v(A+2) is the upper half of a register pair, then v(A+2)' |
| becomes undefined. |
| </li> |
| <li> |
| If A = B-1, then v(B+1)' becomes undefined. |
| </li> |
| <li> |
| If A = B+1, then v(B)' becomes undefined. |
| </li> |
| </ul> |
| |
| <h2>Exceptions</h2> |
| |
| <p> |
| None. |
| </p> |
| |
| </body> |
| </html> |
