
MOTOROLA
Chapter 3. Instruction Set Model
3-23
Instruction Set Summary
word (
lmw
)
instruction with
r
A in the range of registers to be loaded as an invalid
form.
The PowerPC architecture describes some preferred instruction forms for the integer
load and store multiple instructions that may perform better than other forms in some
implementations. None of these preferred forms affect instruction performance in
the G2 core.
When the core is operating with little-endian byte order, execution of a load or store
multiple instruction causes the system alignment error handler to be invoked; see
Section 3.1.2, “Byte Ordering,” in the
Programming Environments Manual
,
for
more information. Table 3-17 lists the integer load and store multiple instructions for
the G2 core.
3.2.4.3.7
Integer Load and Store String Instructions
The integer load and store string instructions allow movement of data from memory to
registers or from registers to memory without concern for alignment. These instructions can
be used for a short move between arbitrary memory locations or to initiate a long move
between misaligned memory fields.
When the core is operating with little-endian byte order, execution of a load or store string
instruction causes the system alignment error handler to be invoked; see Section 3.1.2,
“Byte Ordering,” in the
Programming Environments Manual
,
for more information.
Table 3-18 lists the integer load and store string instructions.
Load string and store string instructions may involve operands that are not word-aligned.
As described in “Alignment Exception (0x00600)” in Chapter 6, “Exceptions,” in the
Programming Environments Manual
, a misaligned string operation suffers a performance
penalty compared to a word-aligned operation of the same type.
Table 3-17. Integer Load and Store Multiple Instructions
Name
Mnemonic
Operand Syntax
Load Multiple Word
lmw
r
D
,
d(
r
A)
Store Multiple Word
stmw
r
S
,
d(
r
A)
Table 3-18. Integer Load and Store String Instructions
Name
Mnemonic
Operand Syntax
Load String Word Immediate
lswi
r
D
,r
A
,
NB
Load String Word Indexed
lswx
r
D
,r
A
,r
B
Store String Word Immediate
stswi
r
S
,r
A
,
NB
Store String Word Indexed
stswx
r
S
,r
A
,r
B
F
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n
.