| The Android Open Source Project | f6c3871 | 2009-03-03 19:28:47 -0800 | [diff] [blame^] | 1 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> |
| 2 | |
| 3 | <html> |
| 4 | |
| 5 | <head> |
| 6 | <title>goto</title> |
| 7 | <link rel=stylesheet href="opcode.css"> |
| 8 | </head> |
| 9 | |
| 10 | <body> |
| 11 | |
| 12 | <h1>goto</h1> |
| 13 | |
| 14 | <h2>Purpose</h2> |
| 15 | |
| 16 | <p> |
| 17 | Unconditionally jump to the indicated instruction. |
| 18 | </p> |
| 19 | <p> |
| 20 | Note: The branch offset may not be 0. (A spin loop may be legally constructed |
| 21 | either with goto/32 or by including a nop as a target before the branch.) |
| 22 | </p> |
| 23 | |
| 24 | <h2>Details</h2> |
| 25 | |
| 26 | <table class="instruc"> |
| 27 | <thead> |
| 28 | <tr> |
| 29 | <th>Op & Format</th> |
| 30 | <th>Mnemonic / Syntax</th> |
| 31 | <th>Arguments</th> |
| 32 | </tr> |
| 33 | </thead> |
| 34 | <tbody> |
| 35 | <tr> |
| 36 | <td>28 10t</td> |
| 37 | <td>goto +AA</td> |
| 38 | <td><code>A:</code> signed branch offset (8 bits)</td> |
| 39 | </tr> |
| 40 | </tbody> |
| 41 | </table> |
| 42 | |
| 43 | <h2>Constraints</h2> |
| 44 | |
| 45 | <ul> |
| 46 | <li> |
| 47 | A must point to a valid bytecode instruction inside the current method. |
| 48 | </li> |
| 49 | <li> |
| 50 | A must not be 0. |
| 51 | </li> |
| 52 | </ul> |
| 53 | |
| 54 | <h2>Behavior</h2> |
| 55 | |
| 56 | <ul> |
| 57 | <li> |
| 58 | The (otherwise invisible) program counter PC is set to the address of the |
| 59 | instruction plus the given offset, that is, PC' = PC(goto) + A. |
| 60 | </li> |
| 61 | <li> |
| 62 | Executions resumes at PC'. |
| 63 | </li> |
| 64 | </ul> |
| 65 | |
| 66 | <h2>Exceptions</h2> |
| 67 | |
| 68 | <p> |
| 69 | None. |
| 70 | </p> |
| 71 | |
| 72 | </body> |
| 73 | </html> |