User's Manual
THE
80286
INSTRUCTION
SET
Table
B·1.
ModRM
Values
Rb
=
AL
CL
OL
BL
AH
CH
OH
BH
Rw
=
AX
CX
OX
BX
SP
BP
SI
01
REG
=
0
1
2 3 4
5
6 7
ModRM values
Effective address
00
08 10 18
20 28
30
38
[BX +
SI]
01
09
11
19
21
29
31
39
[BX +
01]
02
OA
12 1A
22
2A
32 3A [BP + SI]
mod=OO
03
OB
13 1B
23
2B 33 3B [BP +
01]
04
OC
14
1C
24
2C
34
3C
[SI]
05
00
15
10
25
20
35
30
[01]
06
OE
16
1E
26
2E
36
3E
016 (simple var)
07
OF
17
1F 27
2F
37
3F [BX]
40 48
50
58
60 68
70 78
[BX + SI] +
OS(l)
41
49
51
59
61
69
71
79
[BX +
01]
+
OS
42
4A
52
5A
62
6A
72
7A
[BP +
SI]
+
OS
mod=01
43 4B 53 5B
63
6B
73 7B [BP +
01]
+
OS
44
4C
54
5C
64
6C
74
7C
[SI] +
OS
45
40
55
50
65
60
75
70
[01]
+
OS
46
4E
56
5E
66
6E
76
7E
[BP] +
DS(2)
47
4F 57
5F
67
6F
77
7F
[BX] +
D8
SO
88
90
98
AO
AS
BO
BS
[BX + SI] +
016(3)
81
89
91
99
A1
A9
B1
B9 [BX +
01]
+ 016
S2
8A
92
9A
A2
AA
B2 BA
[BP
+SI]
+ 016
mod=10
S3
SB
93
9B
A3
AB
B3 BB [BP +
01]
+ 016
S4
SC
94
9C
A4
AC
B4
BC
[SI] + 016
S5
SO
95
90
A5
AO
B5
BO
[01]
+ 016
S6
SE
96 .
9E
A6
AE
B6
BE
[BP] +
016(2)
87
SF
97 9F
A7
AF
B7 BF [BX] + 016
CO
CS
00
OS
EO
ES
FO
FS
Ew=AX
Eb=AL
C1
C9
01
09
E1
E9
F1
F9
Ew=CX
Eb=CL
C2
CA
02
OA
E2
EA
F2
FA
Ew=OX
Eb=OL
mod=11
C3
CB
03
OB
E3
EB
F3
FB
Ew=BX
Eb=BL
C4
CC
04
OC
E4
EC
F4
FC
Ew=SP
Eb=AH
C5
CO
05
00
E5
EO
F5
FO
Ew=BP
Eb=CH
C6
CE
06
OE
E6
EE
F6
FE
Ew=SI
Eb=OH
C7
CF
07
OF
E7
EF
F7
FF
Ew=OI
Eb=BH
NOTES:
1.
OS
denotes
an
8-bit displacement following the ModRM byte that is sign-extended and added to the
index.
2.
Oefault segment register
is
SS
for
effective addresses containing a
BP
index;
OS
is
for other memory
effective addresses.
3.
016 denotes the 16-bit displacement following the ModRM byte that
is
added to the index.
B-3