CZERO.NEZ

Conditional Zero Not Equal to Zero

CZERO.NEZ rd, rs1, rs2

Moves rs1 to rd if rs2 is zero, otherwise sets rd to zero.

Encoding

Binary Layout

0000111

31:25

rs2

24:20

rs1

19:15

111

14:12

rd

11:7

0110011

6:0

 

Format R-Type

Opcode 0x0E007033

Extension Zicond

Operands

• rd
  Destination register (integer)
• rs1
  Source
• rs2
  Condition

Example

CZERO.NEZ x10, x11, x12

// If x12 != 0, x10=0. Else x10=x11.

Related

Across architectures

Conditional Select (Branchless Move) : how x86, ARM, RISC-V, and PowerISA each do this.

More in Zicond

Reference

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

Description

CZERO.NEZ conditionally zeroes rd: it writes zero to rd if rs2 is non-zero, otherwise writes rs1 to rd. Useful for branch-free conditional selection.

Operation

if (R[rs2] != 0) R[rd] = 0; else R[rd] = R[rs1];