Instruction Syntax

Mnemonic	Format	Description
addic	rD,rA,SIMM	Add immediate carrying

Derived Forms

Mnemonic	Format	Description
subic	rD,rA,value	Subtract immediate carrying (SIMM = -value)

Instruction Encoding

Field	Bits	Description
Primary Opcode	0-5	001100 (0x0C)
rD	6-10	Destination register
rA	11-15	Source register A
SIMM	16-31	16-bit signed immediate value

Operation

rD ← (rA) + EXTS(SIMM)

The sum of the contents of rA and the sign-extended immediate value is placed into rD.

Note: The addic instruction updates the carry bit (XER[CA]) but does not have an overflow exception option.

Affected Registers

XER (Exception Register)

(always)

• CA (Carry)

For more information on condition codes see Section 2.1.5, "XER Register," in the PowerPC Microprocessor Family: The Programming Environments manual.

Examples

Basic Immediate Addition with Carry

addic r3, r1, 100  # r3 = r1 + 100, set carry if overflow
addic r5, r5, -50  # r5 = r5 - 50, set carry if underflow

Multi-Precision Arithmetic Setup

# Start multi-precision addition sequence
addic r3, r1, 0x1000    # Add immediate, set carry
adde r4, r2, r5         # Continue with extended add using carry

Subtract Immediate with Carry (subic)

subic r3, r1, 50   # r3 = r1 - 50 (equivalent to addic r3, r1, -50)

Checking for Overflow in Addition

# Add with carry detection
addic r3, r1, 0x7FFFFFFF  # Add large positive value
# Check XER[CA] to determine if carry occurred

Related Instructions

addi, addic., addc, adde, subfic