infef80386

 

Encoding of 16·bitAddress Mode with "mod rIm" Byte

 

mod rIm

Effective Address

mod rIm

Effective Address

00000

OS:[BX+Sil

 

10000

OS:[BX+SI +d16)

00001

OS:[BX+Oil

 

10001

OS:[BX + 01 + d16)

00010

SS:[BP+Sil

 

10010

SS:[BP+SI+d16)

00011

SS:[BP+Oil

 

10011

SS:[BP+ 01 + d16)

00100

OS:[Sil

 

10100

OS: [SI + d16)

00101

OS:[Oil

 

10101

OS: [01 + d16)

00110

OS:d16

 

10110

SS: [BP + d16)

00111

OS:[BX)

,.

10 111

OS:[BX+d16)

 

 

 

 

 

01000

OS: [BX + SI + dB)

11000

register-see below

01 001

OS: [BX + 01 + dB)

11 001

register-see below

01 010

SS:[BP+SI+dB)

 

11 010

register-see below

01011

SS: [BP + 01 + dB)

11 011

register-see below

01100

OS:[SI+dB)

 

11 100

register-see below

01 101

OS:[OI + dB)

 

11 101

register-see below

01 110

SS:[BP+dB)

 

11 110

register-see below

01 111

OS:[BX+dB)

 

11 111

register-see below

 

 

 

Register Specified by rIm

 

 

 

During 16·BitData Operations

 

 

 

mod rIm

Function of w Field

 

 

 

(when w=O)

(when w = 1)

 

 

 

 

 

 

 

11000

AL

AX

 

 

 

11 001

CL

CX

 

 

 

11 010

OL

OX

 

 

 

11 011

BL

BX

 

 

 

11 100

AH

SP

 

 

 

11 101

CH

BP

 

 

 

11 110

OH

SI

 

 

 

11 111

BH

01

 

 

 

Register Specified by rIm

 

 

 

During 32·BitData Operations

 

 

 

mod rIm

Function of w Field

 

 

 

(when w=O)

(when w = 1)

 

 

 

 

 

 

 

11000

AL

EAX

 

 

 

11 001

CL

ECX

 

 

 

11010

OL

EOX

 

 

 

11 011

BL

EBX

 

 

 

11 100

AH

ESP

 

 

 

11 101

CH

EBP

 

 

 

11 110

OH

ESI

 

 

 

11 111

BH

EOI

12B

Page 189
Image 189
Intel 80386 manual Osbx, OSBX+d16, 11010, Eoi, 12B