Intel Pentium CPU Instruction Set Reference
OR instruction - Logical Inclusive OR
| Code |
Mnemonic |
Description |
| 0C ib |
OR AL, imm8 |
AL OR imm8 |
| 0D iw |
OR AX, imm16 |
AX OR imm16 |
| 0D id |
OR EAX, imm32 |
EAX OR imm32 |
| 80 /1 ib |
OR r/m8, imm8 |
r/m8 OR imm8 |
| 81 /1 iw |
OR r/m16, imm16 |
r/m16 OR imm16 |
| 81 /1 id |
OR r/m32, imm32 |
r/m32 OR imm32 |
| 83 /1 ib |
OR r/m16, imm8 |
r/m16 OR imm8 (sign-extended) |
| 83 /1 ib |
OR r/m32, imm8 |
r/m32 OR imm8 (sign-extended) |
| 08 / r |
OR r/m8, r8 |
r/m8 OR r8 |
| 09 / r |
OR r/m16, r16 |
r/m16 OR r16 |
| 09 / r |
OR r/m32, r32 |
r/m32 OR r32 |
| 0A / r |
OR r8, r/m8 |
r8 OR r/m8 |
| 0B / r |
OR r16, r/m16 |
r16 OR r/m16 |
| 0B / r |
OR r32, r/m32 |
r32 OR r/m32 |
Description
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 0 if both corresponding bits of the operands are 0; otherwise, each bit is 1.
| Operands |
Bytes |
Clocks |
| reg, reg |
2 |
1 |
UV |
| mem, reg |
2 + d(0, 2) |
3 |
UV |
| reg, mem |
2 + d(0, 2) |
2 |
UV |
| reg, imm |
2 + i(1, 2) |
1 |
UV |
| mem, imm |
2 + d(0, 2) + i(1, 2) |
3 |
UV ( not pairable if there is a displacement and immediate) |
| acc, imm |
1 + i(1, 2) |
1 |
UV |
Flags
| ID |
unaffected |
DF |
unaffected |
| VIP |
unaffected |
IF |
unaffected |
| VIF |
unaffected |
TF |
unaffected |
| AC |
unaffected |
SF |
sets according to the result |
| VM |
unaffected |
ZF |
sets according to the result |
| RF |
unaffected |
AF |
undefined |
| NT |
unaffected |
PF |
sets according to the result |
| IOPL |
unaffected |
CF |
cleared |
| OF |
cleared |
