Intel 80287 User Manual

REAL ADDRESS MODE
Since the CS register contains FOOO (thus specifying a code segment starting at physical address FOOOO)
and the instruction pointer contains FFFO, the processor will execute its first instruction at physical
address FFFFOH. The uppermost
16 bytes of physical memory are therefore reserved for initial startup
logic. Ordinarily, this location contains an intersegment direct
JMP instruction whose target is the
actual beginning of a system initialization or restart program.
Some of the steps normally performed by a system initialization routine are as
follows:
Allocate a stack.
Load programs and data from secondary storage into memory.
Initialize external devices.
Enable interrupts (i.e., set the IF bit of the FLAGS register). Set any other desired FLAGS bit
as well.
Set the appropriate MSW flags if a processor extension
is present, or if processor extension functions
are to be emulated by software.
Set other registers,
as appropriate, to the desired initial values.
Execute. (Ordinarily, this last step is performed as an intersegment JMP to the main system
program.)
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Intel 80287 Specifications

General

Brand	Intel
Model	80287
Category	Computer Hardware
Language	English