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TI486 Microprocessor - Al Kossow's Bitsavers

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8MI Handler Example<br />

COMMENT A<br />

This handler turned off the current to the cpu. Before it did, the handler<br />

set a bit in main memory or battery backed-up CMOS indicating that this event<br />

happened. At reset, BIOS will deter.mine that this was the case and "jump"<br />

into the SMI handler. SMI handler will then restore the entire state/context<br />

of the cpu prior to current being removed. The bit in main memory would also<br />

be cleared indicating that the SMI handler had removed current.<br />

mov ax, a<br />

mov ds, ax<br />

mov [485], a<br />

mov ax, cs<br />

mov ds, ax<br />

point to bottom segment<br />

ds segment is now in main memory<br />

clear BIOS flag in main memory<br />

restore ds to SMM area<br />

{Restore Complete CPU State}<br />

eax<br />

ebx<br />

ecx<br />

edx<br />

edi<br />

esi<br />

ebp<br />

esp<br />

cs<br />

ds<br />

ss<br />

es<br />

fs<br />

gs<br />

ldtr<br />

gdtr<br />

idtr<br />

tr<br />

eflags<br />

cra<br />

cr2<br />

cr3<br />

dra<br />

drl<br />

dr2<br />

dr3<br />

dr6<br />

dr7<br />

ccra<br />

ccrl<br />

ccr2<br />

iuse<br />

iuse<br />

iuse<br />

iuse<br />

iuse<br />

iuse<br />

rsdc<br />

rsdc<br />

rsdc<br />

rsdc<br />

rsdc<br />

rsdc<br />

Save the configuration registers with index C3h through FFh<br />

A-20 <strong>TI486</strong> 8MM Programmer's Guide

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