JA80386EXTC25 Datasheet, PDF (23/56 Pages) Intel Corporation – Intel386™ EX Embedded Microprocessor

Intel386™ EX Embedded Microprocessor
5.0
Design Considerations
This section describes the Intel386 EX microprocessor’s instruction set and its component and
revision identifiers.
5.1
Instruction Set
The Intel386 EX microprocessor uses the same instruction set as the Intel386 SX microprocessor
with the following exceptions.
The Intel386 EX microprocessor has one new instruction (RSM). This Resume instruction causes
the processor to exit System Management Mode (SMM). RSM requires 338 clocks per instruction
(CPI).
The Intel386 EX microprocessor requires more clock cycles than the Intel386 SX microprocessor
to execute some instructions. Table 5 lists these instructions and the Intel386 EX microprocessor
clock count. For the equivalent Intel386 SX microprocessor clock count, refer to the “Instruction
Set Clock Count Summary” table in the Intel386™ SX Microprocessor datasheet (order number
240187).
Table 5. Microprocessor Clocks Per Instruction
Instruction
Virtual 8086 Mode⁽²⁾
Clock Count ⁽¹⁾
Real Address Mode
or Virtual 8086 Mode
Protected Virtual Address Mode⁽³⁾
POPA
29
35
IN:
Fixed Port
27
14
8/29
Variable Port
28
15
9/29
OUT:
Fixed Port
27
14
8/29
Variable Port
28
15
9/29
INS
30
17
10/32
OUTS
REP INS
REP OUTS
31
31+6n ^{(Note 4)}
30+8n ^{(Note 4)}
18
17+7n ^{(Note 4)}
16+8n ^{(Note 4)}
11/33
11+7n/32+6n ^{(Note 4)}
10+8n/31+8n ^{(Note 4)}
HLT
7
7
MOV CR0, reg
10
10
NOTES:
1. For IN, OUT, INS, OUTS, REP INS, and REP OUTS instructions, add one clock count for each wait state
generated by the peripheral being accessed (the values in the table are for zero wait state).
2. The clock count values in this column apply if I/O permission allows I/O to the port in virtual 8086 mode. If
the I/O bit map denies permission, exception fault 13 occurs; see clock counts for the INT 3 instruction in
the “Instruction Set Clock Count Summary” table in the Intel386™ SX Microprocessor datasheet (order
number 240187).
3. When two clock counts are listed, the smaller value refers to the case where CPL ≤ IOPL and the larger
value refers to the case where CPL>IOPL. CPL is the current privilege level, and IOPL is the I/O privilege
level.
4. n = the number of times repeated.
Datasheet
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