INTEL386 Просмотр технического описания (PDF) - Intel
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INTEL386 Datasheet PDF : 102 Pages
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Intel386TM SX MICROPROCESSOR
9 2 3 5 ENCODING OF OPERATION DIRECTION
(d) FIELD
In many two-operand instructions the d field is pres-
ent to indicate which operand is considered the
source and which is the destination
d
Direction of Operation
0 Register Memory k- - Register
‘‘reg’’ Field Indicates Source Operand
‘‘mod r m’’ or ‘‘mod ss index base’’ Indicates
Destination Operand
1 Register k- - Register Memory
‘‘reg’’ Field Indicates Destination Operand
‘‘mod r m’’ or ‘‘mod ss index base’’ Indicates
Source Operand
9 2 3 6 ENCODING OF SIGN-EXTEND (s) FIELD
The s field occurs primarily to instructions with im-
mediate data fields The s field has an effect only if
the size of the immediate data is 8 bits and is being
placed in a 16-bit or 32-bit destination
l s
Effect on
Immediate Data8
Effect on
Immediate Data 16 32
0 None
None
1 Sign-Extend Data8
to Fill 16-Bit or 32-Bit
Destination
None
9 2 3 7 ENCODING OF CONDITIONAL TEST
(tttn) FIELD
For the conditional instructions (conditional jumps
and set on condition) tttn is encoded with n indicat-
ing to use the condition (ne0) or its negation (ne1)
and ttt giving the condition to test
Mnemonic
Condition
tttn
O
NO
B NAE
NB AE
EZ
NE NZ
BE NA
NBE A
S
NS
P PE
NP PO
L NGE
NL GE
LE NG
NLE G
Overflow
0000
No Overflow
0001
Below Not Above or Equal
0010
Not Below Above or Equal
0011
Equal Zero
0100
Not Equal Not Zero
0101
Below or Equal Not Above
0110
Not Below or Equal Above
0111
Sign
1000
Not Sign
1001
Parity Parity Even
1010
Not Parity Parity Odd
1011
Less Than Not Greater or Equal 1100
Not Less Than Greater or Equal 1101
Less Than or Equal Greater Than 1110
Not Less or Equal Greater Than 1111
9 2 3 8 ENCODING OF CONTROL OR DEBUG
OR TEST REGISTER (eee) FIELD
For the loading and storing of the Control Debug
and Test registers
When Interpreted as Control Register Field
eee Code
Reg Name
000
CR0
010
CR2
011
CR3
Do not use any other encoding
When Interpreted as Debug Register Field
eee Code
Reg Name
000
DR0
001
DR1
010
DR2
011
DR3
110
DR6
111
DR7
Do not use any other encoding
When Interpreted as Test Register Field
eee Code
Reg Name
110
TR6
111
TR7
Do not use any other encoding
101
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