addme

Add to Minus One Extended

addme RT,RA
addme. RT,RA
addmeo RT,RA
addmeo. RT,RA

Adds the contents of a register and a constant minus one, with optional overflow exception.

Details

The sum (RA) + CA - 1 is placed into register RT. The carry bit (CA) is used in the calculation.

Pseudocode Operation

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

Programming Note

When Rc=1 (dot form), CR0 is updated with the signed comparison of the result against zero (LT, GT, EQ) and the current SO bit from XER.

Extended Mnemonics

Extended Mnemonic Equivalent Instruction

Example

addme r3, r4

Encoding

Binary Layout
31
0
RT
6
RA
11
00000
16
OE
21 22
234
31
Rc
 
Format XO-form
Opcode 0x7C0001D4
Extension Base
Registers Altered CR0, XER

Operands

  • RT
    Target Register
  • RA
    Source Register