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Version 2.03
B.1 Move To/From Special Purpose Register Mnemonics
This section defines extended mnemonics for the
mtspr and mfspr instructions, including the Special
Purpose Registers (SPRs) defined in Book I and certain
privileged SPRs, and for the Move From Time
Base instruction defined in Book II.
The mtspr and mfspr instructions specify an SPR as a
numeric operand; extended mnemonics are provided
that represent the SPR in the mnemonic rather than
requiring it to be coded as an operand. Similar
extended mnemonics are provided for the Move From
Time Base instruction, which specifies the portion of
the Time Base as a numeric operand.
Note: mftb serves as both a basic and an extended
mnemonic. The Assembler will recognize an mftb mnemonic
with two operands as the basic form, and an
mftb mnemonic with one operand as the extended
form. In the extended form the TBR operand is omitted
and assumed to be 268 (the value that corresponds to
TB).
Table 6: Extended mnemonics for moving to/from an SPR
Special Purpose Register
Move To SPR
Move From SPR
Extended Equivalent to Extended Equivalent to
Fixed-Point Exception Register mtxer Rx mtspr 1,Rx mfxer Rx mfspr Rx,1
Link Register mtlr Rx mtspr 8,Rx mflr Rx mfspr Rx,8
Count Register mtctr Rx mtspr 9,Rx mfctr Rx mfspr Rx,9
Decrementer mtdec Rx mtspr 22,Rx mfdec Rx mfspr Rx,22
Save/Restore Register 0 mtsrr0 Rx mtspr 26,Rx mfsrr0 Rx mfspr Rx,26
Save/Restore Register 1 mtsrr1 Rx mtspr 27,Rx mfsrr1 Rx mfspr Rx,27
Special Purpose Registers
G0 through G3
mtsprg n,Rx mtspr 272+n,Rx mfsprg Rx,n mfspr Rx,272+n
Time Base [Lower] mttbl Rx mtspr 284,Rx mftb Rx mfspr Rx,268
Time Base Upper mttbu Rx mtspr 285,Rx mftbu Rx mfspr Rx,269
Processor Version Register - - mfpvr Rx mfspr Rx,287
614
Power ISA -- Book III-E