AMD Geode LX 600@0.7W Data Book page 653

Instruction Set
Notes
The RSM instruction does not check the values that it reads from the SMM header for validity.
The RSM instruction set the current privilege level to the SS DPL value read from the SMM header.
If a RSM restores the processor to real mode, the VM bit of the EFlags register is cleared regardless of the state of the VM
bit in the EFlags value of the SMM header.
If RSM restores the processor to a privilege level that is not 3, then the VM bit of the EFlags register is cleared, regardless
of the contents of the VM bit in the EFlags value of the SMM header.
8.3.4.8 RSTS - Restore Task Register and Descriptor
Opcode Instruction
0F 7D RSTS m80
Operation
IF (CPL<>0 OR (SMM_INST_EN=0 AND SMM=0 AND DMM=0))
#UD;
ELSE
TS.DESCR <= MEM80;
Description
Restore the Task register and descriptor from memory. Below is the format of the descriptor contents in memory.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
BASE[31:24]
BASE[15:0]
Flags Affected
None.
Exceptions
#UD If current privilege level is not 0, or the SMM_INST_EN = 0 and if the processor is not in SMM and if the processor
is not in DMM.
Notes
The reg field within the mod r/m byte must be zero for the RSTS instruction to be recognized.
The RSTS instruction does not check its memory operand for validity. Care should be taken to always load valid data into
the TS.
8.3.4.9 SETALC - Set AL to CF
Opcode Instruction
d6 SETALC
Operation
AL <= {8{CF}};
Description
IF the EFlags CF is set, then the SETALC instruction sets AL to FFh. Otherwise, SETALC sets AL to FFh.
Flags Affected
None.
AMD Geode™ LX Processors Data Book
Clocks
12
G B 0 V LIMIT[19:16]
Clocks
2
Description
Restore TS from memory
8
SELECTOR[15:3]
1 DPL 1 0 E W A
LIMIT[15:0]
Description
Set AL according to CF.
33234H
7 6 5 4 3 2 1 0
TI RPL
BASE[23:16]
+8
+4
+0
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