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User’s Manual
PPC440x5 CPU Core Preliminary
Page 558 of 589
instalfa.fm.
September 12, 2002
Table A-3 lists the reserved opcodes designated by PowerPC Book-E. The decimal value of the secondary
opcode is shown in parentheses after the binary value.
As indicated in the table above, the only preserved opcode which is implemented within the PPC440x5 core
is the mftb instruction. See Preserved Instruction Class on page 55 for more information on PPC440x5
support for this instruction. All other preserved instructions are treated as reserved by PPC440x5 and will
cause Illegal Instruction exception type Program interrupts if their execution is attempted.
The preserved opcode for mftb is included in Table A-5 on page 559, along with all of the defined, allocated,
and reserved-nop class opcodes which are implemented within the PPC440x5 core.
A.5 Reserved Instruction Opcodes
This class of instructions consists of all instruction primary opcodes (and associated extended opcodes, if
applicable) which do not belong to either the defined, allocated, or preserved instruction classes.
Reserved instructions are available for future versions of PowerPC Book-E architecture. That is, future
versions of PowerPC Book-E may define any of these instructions to perform new functions or make them
available for implementation-dependent use as allocated instructions. There are two types of reserved
instructions: reserved-illegal and reserved-nop.
Table A-4 lists the reserved-nop opcodes designated by PowerPC Book-E. In the table, the character “u”
designates a secondary opcode bit which can be set to any value. All other reserved opcodes are in the
reserved-illegal class.
As shown in the table, there are a total of eight (8) secondary opcodes in the reserved-nop class. The
PPC440x5 implements all of the reserved-nop instruction opcodes as true no-ops. These opcodes are
included in Table A-5 on page 559, along with all of the defined, allocated, and preserved class opcodes
which are implemented within the PPC440x5 core.
Table A-3. Preserved Opcodes
Primary
Opcode
Extended
Opcode
Preserved
Mnemonic
PPC440x5
Usage
31 0b0011010010 (210) mtsr
31 0b0011110010 (242) mtsrin
31 0b0101110010 (370) tlbia
31 0b0100110010 (306) tlbie
31 0b0101110011 (371) mftb Yes
31 0b1001010011 (595) mfsr
31 0b1010010011 (659) mfsrin
31 0b0100110110 (310) eciwx
31 0b0110110110 (438) ecowx
Table A-4. Reserved-nop Opcodes
Primary
Opcode
Extended
Opcode
31 0b10uuu10010