INSTRUCTION GROUPS
MOTOROLA INSTRUCTION SET INTRODUCTION 6 - 21
ALU, execute in one instruction cycle. These instructions may affect all of the CCR bits.
Arithmetic instructions are register based (register direct addressing modes used for oper-
ands) so that the data ALU operation indicated by the instruction does not use the XDB,
the YDB, or the global data bus (GDB). Optional data transfers may be specified with most
arithmetic instructions, which allows for parallel data movement over the XDB and YDB
or over the GDB during a data ALU operation. This parallel movement allows new data to
be prefetched for use in subsequent instructions and allows results calculated in previous
instructions to be stored. The following list contains the arithmetic instructions:
Figure 6-12 Special Addressing – I/O Short Address
EXAMPLE: MOVEP A1, X:<<$FFFE
Assembler Syntax: pp
Operands Referenced: X:, Y Memories
Additional Instruction Execution Time (Clocks): 0
Additional Effective Address Words: 0
$FFC0
I/O SHORT
ABSOLUTE
ADDRESS
SPACE
A2 A1 A0
X X 1 2 34 5 6 XXXXXX
55 48 47 24 23 0
7 0 23 0 23 0
BEFORE EXECUTION
A2 A1 A0
X X 1 2 34 5 6 XXXXXX
55 48 47 24 23 0
7 0 23 0 23 0
AFTER EXECUTION
X MEMORY
23 0
00FFFF*
$FFFE
$FFFF
$FFC0
X MEMORY
23 0
003456
$FFFE
$FFFF
*Contents of Bus Control Register (X:$FFFE) After Reset