
2-6
G2 PowerPC Core Reference Manual
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MOTOROLA
Register Set
– Machine state register (MSR). The MSR defines the state of the processor.
The MSR can be modified by the Move to Machine State Register
(
mtmsr
),
System Call (
sc
), and Return from Exception (
rfi
) and Return from Critical
Exception (
rfci
) instructions. It can be read by the Move from Machine State
Register (
mfmsr
) instruction.
Implementation Note
—The G2 core defines MSR[13] as the power
management enable (POW) bit and MSR[14] as the temporary GPR
remapping (TGPR) bit. The G2_LE allocates MSR[24] for enabling the
critical interrupt and
rfci,
the return from critical interrupt instruction.
MSR[31] is used in conjunction with HID2[LET] to indicate the endian mode
of operation of the G2_LE core. These bits are described in Table 2-4.
MPC603e (PID7v)
0x0007
0x0100,
0x0201
Space for future versions
Table 2-4. MSR Bit Settings
Bits
Name
Description
0
—
Reserved. Full function.
1–4
—
Reserved. Partial function.
5–9
—
Reserved. Full function.
10–12
—
Reserved. Partial function.
13
POW
Power management enable (implementation-specific)
0 Disables programmable power modes (normal operation mode)
1 Enables programmable power modes (nap, doze, or sleep mode).
This bit controls the programmable power modes only; it has no effect on dynamic power
management (DPM). MSR[POW] may be altered with an
mtmsr
instruction only. Also, when
altering the POW bit, software may alter only this bit in the MSR and no others. The
mtmsr
instruction must be followed by a context-synchronizing instruction.
See Chapter 10, “Power Management,” for more information.
14
TGPR
Temporary GPR remapping (implementation-specific)
0 Normal operation
1 TGPR mode. GPR0–GPR3 are remapped to TGPR0–TGPR3 for use by TLB miss routines.
The contents of GPR0–GPR3 remain unchanged while MSR[TGPR] = 1. Attempts to use
GPR4–GPR31 with MSR[TGPR] = 1 yield undefined results. Temporarily replaces
TGPR0–TGPR3 with GPR0–GPR3 for use by TLB miss routines. The TGPR bit is set when
either an instruction TLB miss, data read miss, or data write miss exception is taken. The
TGPR bit is cleared by an
rfi
instruction.
Table 2-3. Assigned PVR Values (continued)
Device Name
Version No.
Revision No.
F
Freescale Semiconductor, Inc.
n
.