AMOMAX.D

Atomic Max Doubleword

AMOMAX.D rd, rs2, (rs1)

Atomically updates memory with the maximum of the memory value and register value (64-bit Signed).

Encoding

Binary Layout

10100

31:27

aq

26

rl

25

rs2

24:20

rs1

19:15

011

14:12

rd

11:7

0101111

6:0

 

Format R-Type (Atomic)

Opcode 0xA000302F

Extension A

Operands

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

Example

AMOMAX.D x10, x11, (x12)

// 64-bit atomic max.

Related

More in A

Reference

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

Description

AMOMAX.D performs an atomic signed maximum doubleword operation (RV64 only).

Operation

temp = M[R[rs1]]; M[R[rs1]] = max(temp, R[rs2]); R[rd] = temp;