Outils pour utilisateurs
back2root:ibm-pc-ms-dos:instr:rep
Différences
Ci-dessous, les différences entre deux révisions de la page.
| Prochaine révision | Révision précédenteProchaine révisionLes deux révisions suivantes | ||
| back2root:ibm-pc-ms-dos:asm:instr:rep [2023/01/20 21:08] – créée frater | back2root:ibm-pc-ms-dos:instr:rep [2023/02/24 14:16] – supprimée - modification externe (Unknown date) 127.0.0.1 | ||
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| Ligne 1: | Ligne 1: | ||
| - | ====== REP ====== | ||
| - | |||
| - | ===== REP - Repeat String Operation ===== | ||
| - | |||
| - | Repeats execution of string instructions while CX != 0. After each string operation, CX is decremented and the Zero Flag is tested. | ||
| - | |||
| - | **Usage:** | ||
| - | <code asm> | ||
| - | INSTR Opp, | ||
| - | </ | ||
| - | |||
| - | The combination of a repeat prefix and a segment override on CPU's before the 386 may result in errors if an interrupt occurs before CX=0. The following code shows code that is susceptible to this and how to avoid it: | ||
| - | |||
| - | <code asm> | ||
| - | again: | ||
| - | jcxz next ; | ||
| - | loop again ; | ||
| - | next: | ||
| - | </ | ||
| - | |||
| - | **Modifies flags: | ||
| - | |||
| - | <WRAP round box> | ||
| - | CF PF AF ZF SF TF IF DF OF <color # | ||
| - | |||
| - | <color # | ||
| - | </ | ||
| - | |||
| - | ^ ^ Clocks | ||
| - | ^ Operands | ||
| - | | none | ||
| - | | none (PM) | - | ||
| - | | reg, | ||
| - | | mem, | ||
| - | | reg, | ||
| - | | reg, | ||
| - | | mem, | ||
| - | | accum, | ||
| - | |||
| - | {{page>: | ||
back2root/ibm-pc-ms-dos/instr/rep.txt · Dernière modification : 2023/02/24 14:16 de frater
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