AMOSWAP.W

Atomic Swap Word

AMOSWAP.W rd, rs2, (rs1)

Atomically swaps a value in memory with a register.

Encoding

Binary Layout

00001

31:27

aq

26

rl

25

rs2

24:20

rs1

19:15

010

14:12

rd

11:7

0101111

6:0

 

Format R-Type (Atomic)

Opcode 0x0800202F

Extension A

Operands

• rd
  Dest (Old Value)
• rs2
  New Value
• rs1
  Address

Example

AMOSWAP.W x10, x11, (x12)

// Writes x11 to memory at x12, loads old memory value into x10.

Related

More in A

Reference

View in RISC-V Unprivileged ISA Specification ↗ RISC-V ISA Manual

Description

AMOSWAP.W atomically loads a word from the address in rs1 into rd and stores the value of rs2 to that address.

Operation

temp = M[R[rs1]]; M[R[rs1]] = R[rs2]; R[rd] = temp;