rldic

Rotate Left Doubleword Immediate Clear

rldic RT,RA,RB,MB
rldic. RT,RA,RB,MB

Rotates a 64-bit register left, then clears bits based on a mask. 64-bit equivalent of rlwinm.

Details

The contents of register RS are rotated64 left SH bits. A mask is generated having 1-bits from bit MB through bit 63-SH and 0-bits elsewhere. The rotated data are ANDed with the generated mask and the result is placed into register RA.

Pseudocode Operation

if 'rldic' then
    SH ← sh5 || sh0:4
    r ← ROTL64((RS), SH)
    MB ← mb5 || mb0:4
    m ← MASK(MB, 63-SH)
    RA ← r & m

Programming Note

rldic can be used to clear the high-order b bits of the contents of a register and then shift the result left by n bits, by setting SH=n and MB=b-n. It can be used to clear the high-order n bits of a register, by setting SH=0 and MB=n.

Extended Mnemonics

Extended Mnemonic Equivalent Instruction
clrlsldi
clrlsldi.RA,RS,b,n

Example

rldic r3, r4, 4, 10

// Rotate left 4, clear bits 0-9.

Encoding

Binary Layout
30
0
RS
6
RA
11
SH
16
MB
21
2
27
sh Rc
30 31
 
Format MD-form
Opcode 0x78000008
Extension Base
Registers Altered CR0

Operands

  • RA
    Target
  • RS
    Source
  • SH
    Shift Amount
  • MB
    Mask Begin
  • RT
    Target General Purpose Register
  • RB
    Immediate Value for SH (Shift Amount)