std

Store Doubleword

std RS, DS(RA)

Stores a 64-bit doubleword to memory.

Details

The stw instruction stores the lower 32 bits of a doubleword from register RS into memory at the effective address (EA), which is calculated as the sum of the contents of register RA and the sign-extended displacement D. If RA is zero, EA is considered to be zero.

Pseudocode Operation

MEM(EA, 8) <- RS

Programming Note

The std instruction stores a doubleword from a source register into memory. Ensure that the destination address is properly aligned to avoid performance penalties or exceptions. This instruction operates at user privilege level and will raise an exception if the EA is out of bounds.

Example

std r3, 16(r4)

Encoding

Binary Layout
62
0
RS
6
RA
11
DS
16
00
30
 
Format DS-form
Opcode 0xF8000000
Extension Base

Operands

  • RS
    Source Register
  • DS
    Displacement (Multiple of 4)
  • RA
    Base Register