ori
OR Immediate
ori R31,R31,0
Performs a bitwise OR operation between the contents of a register and an immediate value, placing the result in another register.
Details
Performs a bitwise OR between a general-purpose register and a 16-bit unsigned immediate value, storing the result in another register. This is a base category instruction with no condition register or status updates.
Pseudocode Operation
RA ← RS | (0x0000 || UI)Programming Note
Warning: Other forms of ori Rx,Rx,0 that are not described in this section may also have micro-architectural effects on program execution. Use of these forms should be avoided except when software needs the associated micro-architectural effects. Programming Note: This no-op is intended to be used by software for providing protection against the Spectre class of transient execution attacks by restricting eventually discarded out-of-order execution effects with transient register values, which may compromise confidential data via other covert channels.
Extended Mnemonics
| Extended Mnemonic | Equivalent Instruction |
|---|---|
| nop | |
Example
// Set bit 0.
Encoding
Operands
-
RA
Target Register -
RS
Source Register -
UI
Unsigned 16-bit Immediate -
RT
Target General Purpose Register -
SImm
Sign-Extended 16-bit Immediate Value