AMD Geode LX 800@0.9W - Manual (Page 193)

AMD Geode™ LX Processors Data Book 193
CPU Core Register Descriptions 33234H
5.5.2.103 Power Mode MSR (PMODE_MSR)
This MSR enables some modules to turn their clocks off when they are idle to save power. Most of these bits are off by
default. It is recommended that they be set by BIOS.
MSR Address 00001930h
Type R/W
Reset Value 00000000_00000300h
PMODE_MSR Register Map
63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32
RSVD
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RSVD
IRS_IF
IRS_IMT
A
G
IRS_IMD
A
T
A RSVD
FPU_
EX
FPU_F
P
RSVD
BCL
2_MSR
BCL2_GA
T
ED
PMODE_MSR Bit Descriptions
Bit Name Description
63:19 RSVD Reserved.
18 IRS_IF Reserved, Instruction Fetch. Reserved for possible future clock gating of IF.
(Default = 0)
17 IRS_IMTAG Reserved, Instruction Memory Subsystem. Reserved for possible future clock gating
IM tag. (Default = 0)
16 IRS_IMDATA Instruction Memory Subsystem Data. When bit is set, IM may turn off the clock when
IM_DATA is idle. (Default = 0)
9 FPU_EX FPU EX. When bit is set, FPU may turn off the clock to FPU Region 1 when FP_EX is
idle. (Default = 1)
8 FPU_FP FPU_FP. When bit is set, FPU may turn off the clock to FPU Region 2 when FPU is idle.
(Default = 1)
1 BCL2_MSR BCL2 MSR. When bit is set, BCL2 may turn off the clock to BC Region 1 when
BCL2_MSR is idle. (Default = 0)
0 BCL2_GATED BCL2 Gated. When bit is set, BCL2 may turn off the clock to BC Region 2 when BCL2 is
idle. (Default = 0)