adda.md

ADDA - Add address

Operation

[destination] ← [source] + [destination]

Syntax

ADDA <ea>,An

Attributes

Size word, longword

Description

Add the source operand to the destination address register and store the result in the destination address register. The source is sign-extended before it is added to the destination. For example, if we execute ADDA.W D3,A4 where A4 = 00000100₁₆ and D3.W = 8002₁₆, the contents of D3 are sign-extended to FFFF8002₁₆ and added to 00000100₁₆ to give FFFF8102₁₆, which is stored in A4.

Application

To add to the contents of an address register and not update the CCR. Note that ADDA.W D0,A0 is the same as LEA (A0,D0.W),A0.

Condition codes

X	N	Z	V	C
-	-	-	-	-

An ADDA operation does not affect the state of the CCR.

Source operand addressing modes

Dn	An	(An)	(An)+	‑(An)	(d,An)	(d,An,Xi)	ABS.W	ABS.L	(d,PC)	(d,PC,Xn)	imm
✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓

From MOTOROLA M68000 FAMILY Programmer's reference manual. Copyright 1992 by Motorola Inc./NXP. Adapted with permission.