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add

Operation

rc -< rA + rB

Assembler Syntax

add rC, rA, rB

Example

add r6, r7, r8

Description

Calculates the sum of rA and rB.  Stores the result in rC.  Used for both signed and unsigned addition.

Usage

Carry Detection (unsigned operands)

Following . . .

add rC, rA, rB         ; The original add operation
cmpltu rD, rC, rA      ; rD is written with the carry bit

add rC, rA, rB         ; The original add operation
bltu rC, rA, label     ; Branch if carry was generated

Overflow Detection (signed operands)

etc.

Operation:

rc <- rA + rB

Assembler Syntax:

add

Example:

add

add rC, rA, rB        ; The original add operation
cmpltu rD, rC, rA     ; rD is written with the carry bit