
MOTOROLA
Chapter 3. Instruction Set Model
3-11
Instruction Set Summary
exception) handler to be invoked. The core provides the following supervisor-level
instructions:
dcbi
(this instruction should never be used on the G2 core),
mfmsr
,
mfspr
,
mfsr
,
mfsrin
,
mtmsr
,
mtspr
,
mtsr
,
mtsrin
,
rfi
,
tlbie
,
tlbsync
,
tlbld
, and
tlbli
. Note that the privilege level of the
mfspr
and
mtspr
instructions depends on
the SPR encoding.
An attempt to access memory that is not available (page fault) causes the ISI
exception handler to be invoked.
An attempt to access memory with an effective address alignment that is invalid for
the instruction causes the alignment exception handler to be invoked.
The execution of an
sc
instruction invokes the system call exception handler that
permits a program to request the system to perform a service.
The execution of a trap instruction invokes the program exception trap handler.
The execution of a floating-point instruction when floating-point instructions are
disabled or unavailable invokes the floating-point unavailable exception handler.
The execution of an instruction that causes a floating-point exception while
exceptions are enabled
in the MSR invokes the program exception handler.
Exceptions caused by asynchronous events are described in Chapter 5, “Exceptions.”
3.2.3
Instruction Set Overview
This section provides a brief overview of the PowerPC instructions implemented in the core
and highlights any special information with respect to how the G2 core implements a
particular instruction. Note that the categories used in this section correspond to those used
in Chapter 4, “Addressing Modes and Instruction Set Summary,” in the
Programming
Environments Manual
. These categorizations are somewhat arbitrary and are provided for
the convenience of the programmer and do not necessarily reflect the PowerPC architecture
specification.
Note that some of the instructions have the following optional features:
CR Update—The dot (
.
) suffix on the mnemonic enables the update of the CR.
Overflow option—The
o
suffix indicates that the overflow bit in the XER is enabled.
3.2.4
PowerPC UISA Instructions
The UISA includes the base user-level instruction set (excluding a few user-level cache
control, synchronization, and time base instructions), user-level registers, programming
model, data types, and addressing modes. This section discusses the instructions defined in
the UISA.
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n
.