IA186EM_04 Datasheet, PDF (88/133 Pages) InnovASIC, Inc – 8/16-Bit Microcontrollers

IA186EM/IA188EM
8/16-BIT Microcontrollers
Data Sheet
As of Production Version -03
Segment Override Prefix
The Operand Address byte is configured as follows.
7
6
5
4
3
2
1
0
0
0
1 SR SR 1
1
0
SR Segment Register
00 ES
01 CS
10 SS
11 DS
Notation
Parameter
Indication
:
The component of the left is the segment for a component located in
memory. The component on the right is the offset.
:: The component of the left is concatenated with the component on the right.
Operand
imm8
imm16
m
m8
m16
r/m8
r/m16
Translation
Immediate byte: signed number between –128 and 127
Immediate word: signed number between –32768 and 32767
Operand in memory
Byte string in memory pointed to by DS:SI or ES:DI
Word string in memory pointed to by DS:SI or ES:DI
General byte register or a byte in memory
General word register or a word in memory
Opcode
Parameter
/0 - /7
The Auxiliary Field in the Operand Address byte specifies an extension (from 000 to 111,
i.e. 0 to 7) to the opcode instead of a register. Thus the opcode for adding (AND) an
immediate byte to a general byte register or a byte in memory is ‘80 /4 ib’. This indicates
that the second byte of the opcode is ‘mod 100 r/m’.
/r
The Auxiliary Field in the Operand Address byte specifies a register rather that an opcode
extension. The opcode byte specifies which register, either byte size or word size, is
assigned as in the aux code above.
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