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TI486 Microprocessor - Al Kossow's Bitsavers

TI486 Microprocessor - Al Kossow's Bitsavers

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8MI Handler Example<br />

set bit in main memory to indicate to the BIOS that SMI handler<br />

turned power off to CPU and CPU state should be restored by<br />

the SMI handler<br />

mov ax, 0<br />

mov ds, ax<br />

mov [485], 1<br />

point to bottom segment<br />

ds segment is now in main memory<br />

set BIOS flag in memory<br />

(save entire CPU state. See Restore CPU state label)<br />

(Chip set specific instructions to be executed to remove power to<br />

cpu)<br />

jmp end_timer<br />

reset_timer:<br />

Chip set specific instructions to turn off peripheral and enable<br />

chip set I/O trapping of the devices io range or enable timer<br />

to allow polling of peripheral requirements.<br />

jmp end_timer<br />

Chip set specific instructions to be executed to reset a timer and<br />

possibly increment a counter to maintain number to time out occurred<br />

for a particular device.<br />

j mp end_timer<br />

jmp done<br />

A-18<br />

<strong>TI486</strong> 8MM Programmer's Guide

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