ld

Load Doubleword

ld RT, DS(RA)

Loads a doubleword (64 bits) from memory.

Encoding

Binary Layout

0

0:5

RT

6:10

RA

11:15

DS

16:20

0

21:30

31

31

 

Format DS-form

Opcode 0xE8000000

Extension Base

Operands

• RT
  Target Register
• DS
  Displacement (14-bit Signed, Multiple of 4)
• RA
  Base Register
• disp
  Displacement value

Example

ld r3, 16(r4)

// Load 64-bit value.

Related

More in Base

Reference

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

Description

The doubleword in storage addressed by EA is loaded into RT. The effective address (EA) is the sum of RA and disp, sign-extended to 64 bits.

Operation

if 'ld' then
    EA ← (RA|0) + EXTS64(DS||0b00)
    RT ← MEM(EA, 8)

Programming Note

The ld instruction loads a doubleword from memory into a register. Ensure the address is properly aligned to avoid alignment faults. This instruction operates at user privilege level and will raise an exception if the EA is out of bounds or access permissions are violated.