extldi

Extract and Left Justify Immediate

extldi ra,rs,n,b (n > 0)

Extracts a field of n bits starting at bit position b in the source register, left justifies this field in the target register, and clears all other bits of the target register to 0.

Encoding

Binary Layout

0:5

6:29

Format XO-form

Opcode 0x78000004

Extension Base

Operands

ra
Target General Purpose Register
rs
Source General Purpose Register
n
Number of bits to extract
b
Starting bit position

Example

extldi ra, rs, n, b (n > 0)

Reference

View in PowerISA v3.1C Specification ↗ OPF Power ISA v3.1C

Description

For extldi, the field of n bits starting at bit position b in the source register is extracted, left justified in the target register, and all other bits are cleared to 0.

Operation

if 'extldi' then
    ra <- (rs >> b) & ((1 << n) - 1)

Programming Note

Use extldi to extract a specific bit field from a source register, left-justifying it in the target register. Ensure that the bit position and length are correctly specified to avoid data corruption. This instruction operates at user privilege level.