ST486SMM View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST486SMM' PDF : 34 Pages View PDF
ST486DX - SMM SOFTWARE CONSIDERATIONS
save other registers and access data in SMM memory. To use any other register the SMM program-
mer must first save the contents using the SVDC instruction for segment registers or MOV opera-
tions for general purpose registers (See SGS Thomson SMM instruction description Section 2.3).
It is possible to save all the CPU registers as needed. See Section 3.3 for an example saving and re-
storing the entire CPU state.
31
Top of SMM
Address Space
31
31
0
DR7
-4h
EFLAGS
-8h
CR0
-Ch
Current IP
Next IP
16 15
-10h
0 -14h
Reserved
CS Selector
-18h
CS Descriptor (Bits 63-32)
-1Ch
CS Descriptor (Bits 31-0)
3 2 10
-20h
Reserved
I/O Write Data Size
16 15
S PI
I/O Write Address
-24h
-28h
I/O Write Data
-2Ch
ESI or EDI
-30h
1713503
Figure 3 - 1. SMM Memory Space Header
25
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