Intel 80286 User Manual

PROTECTION
Table 7-4. Inter-Level Return Checks
Type of Check Exception·
Error Code
SP is not within Segment Limit
SF
0
SP + N + 7 is not in Segment Limit·
SF
0
RPL of Return CS is Greater than CPL
GP Return CS id
Return
CS Selector is not null
GP Return CS id
Return
CS segment is within Descriptor Table Limit
GP Return CS id
Return
CS Descriptor is a Code Segment
GP Return CS id
Return
CS Segment is Present
NP Return CS id
DPL
of Return Non-Conforming Code Segment RPL of CS GP
Return CS id
55 Selector at SP + N + 6 is not Null SF Return 55 id
55 Selector at SP + N + 6 is within Descriptor Table Limit SF Return 55 id
55 Descriptor is Writable Data Segment
SF Return 55 id
55 Segment is Present
SF Return 55 id
55 Segment DPL = RPL of CS
SF Return 55 id
'SF = Stack Fault, GP = General Protection Exception, NP = Not-Present Exception
7-22
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Intel 80286 Specifications

General

Processor Type	Microprocessor
Clock Speed	6 MHz to 25 MHz
Transistor Count	134, 000
Addressable Memory	16 MB
Instruction Set	x86
Architecture	x86
Data Bus Width	16-bit
Address Bus Width	24-bit
Operating Modes	Real mode, Protected mode
Process Technology	1.5 µm
Voltage	5V
Introduced	1982
Package	68-pin PGA