addme.

Add to Minus One Extended

addme. RT,RA,RB

Adds the contents of two registers and subtracts one, then updates the condition register.

Details

For addme., the sum of the contents of register RA and RB minus one is placed into register RT.

Pseudocode Operation

if 'addme.' then
    RT <- (RA) + (RB) - 1

Programming Note

The addme. instruction adds two registers, subtracts one from the result, and stores it in a third register. It updates the CR0 and XER special registers with the arithmetic results. Ensure that the input registers RA and RB are correctly aligned for optimal performance. This instruction is available at user privilege level.

Example

addme. r3, r4, r5

Encoding

Binary Layout
31
0
RT
6
RA
11
/
16
0
21
234
22
Rc
31
 
Format XO-form
Opcode 0x7C0001D5
Extension Base
Registers Altered CR0, XER

Operands

  • RT
    Target General Purpose Register
  • RA
    Source General Purpose Register
  • RB
    Source General Purpose Register