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| <title>OR—Logical Inclusive OR </title></head> |
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| <h1>OR—Logical Inclusive OR</h1> |
| <table> |
| <tr> |
| <th>Opcode</th> |
| <th>Instruction</th> |
| <th>Op/En</th> |
| <th>64-Bit Mode</th> |
| <th>Compat/Leg Mode</th> |
| <th>Description</th></tr> |
| <tr> |
| <td>0C <em>ib</em></td> |
| <td>OR AL, i<em>mm8</em></td> |
| <td>I</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td>AL OR <em>imm8.</em></td></tr> |
| <tr> |
| <td>0D <em>iw</em></td> |
| <td>OR AX, i<em>mm16</em></td> |
| <td>I</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td>AX OR <em>imm16.</em></td></tr> |
| <tr> |
| <td>0D <em>id</em></td> |
| <td>OR EAX, i<em>mm32</em></td> |
| <td>I</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td>EAX OR <em>imm32.</em></td></tr> |
| <tr> |
| <td>REX.W + 0D <em>id</em></td> |
| <td>OR RAX, i<em>mm32</em></td> |
| <td>I</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td>RAX OR <em>imm32 (sign-extended).</em></td></tr> |
| <tr> |
| <td>80 /1 <em>ib</em></td> |
| <td>OR <em>r/m8, imm8</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r/m8 </em>OR<em> imm8.</em></td></tr> |
| <tr> |
| <td>REX + 80 /1 <em>ib</em></td> |
| <td>OR <em>r/m8*, imm8</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td><em>r/m8 </em>OR<em> imm8.</em></td></tr> |
| <tr> |
| <td>81 /1 <em>iw</em></td> |
| <td>OR <em>r/m16, imm16</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td> <em>r/m16 </em>OR <em>imm16.</em></td></tr> |
| <tr> |
| <td>81 /1 <em>id</em></td> |
| <td>OR <em>r/m32, imm32</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td> <em>r/m32 </em>OR <em>imm32.</em></td></tr> |
| <tr> |
| <td>REX.W + 81 /1 <em>id</em></td> |
| <td>OR <em>r/m64, imm32</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td> <em>r/m64 </em>OR <em>imm32 (sign-extended).</em></td></tr> |
| <tr> |
| <td>83 /1 <em>ib</em></td> |
| <td>OR <em>r/m16, imm8</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r/m16 </em>OR <em>imm8 (sign-extended).</em></td></tr> |
| <tr> |
| <td>83 /1 <em>ib</em></td> |
| <td>OR <em>r/m32, imm8</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r/m32 </em>OR <em>imm8 (sign-extended).</em></td></tr> |
| <tr> |
| <td>REX.W + 83 /1 <em>ib</em></td> |
| <td>OR <em>r/m64, imm8</em></td> |
| <td>MI</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td><em>r/m64 </em>OR <em>imm8 (sign-extended).</em></td></tr> |
| <tr> |
| <td>08 /<em>r</em></td> |
| <td>OR <em>r/m8, r8</em></td> |
| <td>MR</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r/m8 </em>OR<em> r8.</em></td></tr> |
| <tr> |
| <td>REX + 08 /<em>r</em></td> |
| <td>OR <em>r/m8*, r8*</em></td> |
| <td>MR</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td><em>r/m8 </em>OR<em> r8.</em></td></tr> |
| <tr> |
| <td>09 /<em>r</em></td> |
| <td>OR <em>r/m16, r16</em></td> |
| <td>MR</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r/m16 </em>OR <em>r16.</em></td></tr> |
| <tr> |
| <td>09 /<em>r</em></td> |
| <td>OR <em>r/m32, r32</em></td> |
| <td>MR</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r/m32 </em>OR<em> r32.</em></td></tr> |
| <tr> |
| <td>REX.W + 09 /<em>r</em></td> |
| <td>OR <em>r/m64, r64</em></td> |
| <td>MR</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td><em>r/m64 </em>OR<em> r64.</em></td></tr> |
| <tr> |
| <td>0A /<em>r</em></td> |
| <td>OR <em>r8, r/m8</em></td> |
| <td>RM</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r8 </em>OR <em>r/m8.</em></td></tr> |
| <tr> |
| <td>REX + 0A /<em>r</em></td> |
| <td>OR <em>r8*, r/m8*</em></td> |
| <td>RM</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td><em>r8 </em>OR <em>r/m8.</em></td></tr> |
| <tr> |
| <td>0B /<em>r</em></td> |
| <td>OR <em>r16, r/m16</em></td> |
| <td>RM</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r16 </em>OR <em>r/m16.</em></td></tr> |
| <tr> |
| <td>0B /<em>r</em></td> |
| <td>OR <em>r32, r/m32</em></td> |
| <td>RM</td> |
| <td>Valid</td> |
| <td>Valid</td> |
| <td><em>r32 </em>OR <em>r/m32.</em></td></tr> |
| <tr> |
| <td>REX.W + 0B /<em>r</em></td> |
| <td>OR <em>r64, r/m64</em></td> |
| <td>RM</td> |
| <td>Valid</td> |
| <td>N.E.</td> |
| <td><em>r64 </em>OR <em>r/m64.</em></td></tr></table> |
| <p><strong>NOTES:</strong></p> |
| <p>*</p> |
| <p>In 64-bit mode, r/m8 can not be encoded to access the following byte registers if a REX prefix is used: AH, BH, CH, DH.</p> |
| <h3>Instruction Operand Encoding</h3> |
| <table> |
| <tr> |
| <td>Op/En</td> |
| <td>Operand 1</td> |
| <td>Operand 2</td> |
| <td>Operand 3</td> |
| <td>Operand 4</td></tr> |
| <tr> |
| <td>I</td> |
| <td>AL/AX/EAX/RAX</td> |
| <td>imm8/16/32</td> |
| <td>NA</td> |
| <td>NA</td></tr> |
| <tr> |
| <td>MI</td> |
| <td>ModRM:r/m (r, w)</td> |
| <td>imm8/16/32</td> |
| <td>NA</td> |
| <td>NA</td></tr> |
| <tr> |
| <td>MR</td> |
| <td>ModRM:r/m (r, w)</td> |
| <td>ModRM:reg (r)</td> |
| <td>NA</td> |
| <td>NA</td></tr> |
| <tr> |
| <td>RM</td> |
| <td>ModRM:reg (r, w)</td> |
| <td>ModRM:r/m (r)</td> |
| <td>NA</td> |
| <td>NA</td></tr></table> |
| <h2>Description</h2> |
| <p>Performs a bitwise inclusive OR operation between the destination (first) and source (second) operands and stores the result in the destination operand location. The source operand can be an immediate, a register, or a memory location; the destination operand can be a register or a memory location. (However, two memory operands cannot be used in one instruction.) Each bit of the result of the OR instruction is set to 0 if both corresponding bits of the first and second operands are 0; otherwise, each bit is set to 1.</p> |
| <p>This instruction can be used with a LOCK prefix to allow the instruction to be executed atomically.</p> |
| <p>In 64-bit mode, the instruction’s default operation size is 32 bits. Using a REX prefix in the form of REX.R permits access to additional registers (R8-R15). Using a REX prefix in the form of REX.W promotes operation to 64 bits. See the summary chart at the beginning of this section for encoding data and limits.</p> |
| <h2>Operation</h2> |
| <pre>DEST ← DEST OR SRC;</pre> |
| <h2>Flags Affected</h2> |
| <p>The OF and CF flags are cleared; the SF, ZF, and PF flags are set according to the result. The state of the AF flag is undefined.</p> |
| <h2>Protected Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>#GP(0)</td> |
| <td> |
| <p>If the destination operand points to a non-writable segment.</p> |
| <p>If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.</p> |
| <p>If the DS, ES, FS, or GS register contains a NULL segment selector.</p></td></tr> |
| <tr> |
| <td>#SS(0)</td> |
| <td>If a memory operand effective address is outside the SS segment limit.</td></tr> |
| <tr> |
| <td>#PF(fault-code)</td> |
| <td>If a page fault occurs.</td></tr> |
| <tr> |
| <td>#AC(0)</td> |
| <td>If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.</td></tr> |
| <tr> |
| <td>#UD</td> |
| <td>If the LOCK prefix is used but the destination is not a memory operand.</td></tr></table> |
| <h2>Real-Address Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>#GP</td> |
| <td>If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.</td></tr> |
| <tr> |
| <td>#SS</td> |
| <td>If a memory operand effective address is outside the SS segment limit.</td></tr> |
| <tr> |
| <td>#UD</td> |
| <td>If the LOCK prefix is used but the destination is not a memory operand.</td></tr></table> |
| <h2>Virtual-8086 Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>#GP(0)</td> |
| <td>If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit.</td></tr> |
| <tr> |
| <td>#SS(0)</td> |
| <td>If a memory operand effective address is outside the SS segment limit.</td></tr> |
| <tr> |
| <td>#PF(fault-code)</td> |
| <td>If a page fault occurs.</td></tr> |
| <tr> |
| <td>#AC(0)</td> |
| <td>If alignment checking is enabled and an unaligned memory reference is made.</td></tr> |
| <tr> |
| <td>#UD</td> |
| <td>If the LOCK prefix is used but the destination is not a memory operand.</td></tr></table> |
| <h2>Compatibility Mode Exceptions</h2> |
| <p>Same as for protected mode exceptions.</p> |
| <h2>64-Bit Mode Exceptions</h2> |
| <table class="exception-table"> |
| <tr> |
| <td>#SS(0)</td> |
| <td>If a memory address referencing the SS segment is in a non-canonical form.</td></tr> |
| <tr> |
| <td>#GP(0)</td> |
| <td>If the memory address is in a non-canonical form.</td></tr> |
| <tr> |
| <td>#PF(fault-code)</td> |
| <td>If a page fault occurs.</td></tr> |
| <tr> |
| <td>#AC(0)</td> |
| <td>If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.</td></tr> |
| <tr> |
| <td>#UD</td> |
| <td>If the LOCK prefix is used but the destination is not a memory operand.</td></tr></table></body></html> |