SH1ADD

Shift Left 1 and Add

SH1ADD rd, rs1, rs2

Shifts rs1 left by 1 and adds rs2. Used for calculating addresses of 16-bit elements.

Encoding

Binary Layout

0010000

31:25

rs2

24:20

rs1

19:15

010

14:12

rd

11:7

0110011

6:0

 

Format R-Type

Opcode 0x20002033

Extension Zba

Operands

• rd
  Destination register (integer)
• rs1
  Index
• rs2
  Base

Example

SH1ADD x10, x11, x12

// Calculate address: x12 + (x11 * 2).

Related

More in Zba

Reference

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

Description

SH1ADD shifts rs1 left by 1 bit, then adds the result to rs2, writing to rd. Used for stride-1 array indexing (byte element + base).

Operation

R[rd] = R[rs2] + (R[rs1] << 1);