Download Chapter 2 (cont.)

EE314
Microprocessor Systems
Chapter 3
80x86 Instruction, Part 1: Addressing Modes,
Flags, Data Transfer, and String Instructions
Objectives:
The style of source files written in 80x86 assembly language
The different addressing modes of the 80x86
The operation and use of the processor flags
Data transfer and string instructions
Based on "An Introduction to the Intel Family of Microprocessors" by James L. Antonakos
3.2 Assembly language programming
Source file
(TOTAL.ASM)
Assembler
Object files
...
List file
(TOTAL.LST)
Object file
(TOTAL.OBJ)
Linker
Final object file or executable file
Library
3.2 Assembly language programming
A Sample Source File
8000 B8
8001 00
8002 70
DATA
Data name
Label
POINTS
SUM
DATA
CODE
1
2
3
4
5
6
7
8
9
10
11
12
13
8000
8000
8003
8005
8007
8009
800C
800E
800F
8011
8013
8015
B8 7000
8E D8
B0 00
B3 10
BE 0000
02 04
46
FE CB
75 F9
88 04
CB
TOTAL:
ADDUP:
CODE
Begin of Data segment
SEGMENT PARA ‘DATA’
ORG
7000H
DB
16 DUP (?)
DB
(?)
ENDS
End Segment
SEGMENT PARA ‘CODE’
ASSUME CS:CODE, DS:DATA
ORG
MOV
MOV
MOV
MOV
MOV
ADD
INC
DEC
JNZ
MOV
RET
ENDS
END
END
8000H
AX,7000H
DS,AX
AL,0
BL,16
SI,0
AL,[SI]
SI
BL
ADDUP
[SI],AL
Begin of Code segment
;load address of data area;
;init data segment register
;clear result
;init loop counter
;init data pointer
;add data value to result
;increment data pointer
;decrement loop counter
;jump if counter not zero
;save sum
;return
TOTAL
End Source file
Start execution address
3.2 Assembly language programming
A Sample Source File
POINTS
SUM
1
2
3
4
5
6
7
8
9
10
11
12
13
8000
8000
8003
8005
8007
8009
800C
800E
800F
8011
8013
8015
B8 7000
8E D8
B0 00
B3 10
BE 0000
02 04
46
FE CB
75 F9
88 04
CB
TOTAL:
ADDUP:
.MODEL
.DATA
ORG
DB
DB
.CODE
ORG
MOV
MOV
MOV
MOV
MOV
ADD
INC
DEC
JNZ
MOV
RET
END
SMALL
7000H
16 DUP (?)
(?)
8000H
AX,7000H
DS,AX
AL,0
BL,16
SI,0
AL,[SI]
SI
BL
ADDUP
[SI],AL
TOTAL
;load address of data area;
;init data segment register
;clear result
;init loop counter
;init data pointer
;add data value to result
;increment data pointer
;decrement loop counter
;jump if counter not zero
;save sum
;return
3.2 Assembly language programming
Predefined .MODEL types
Memory
Model
Data
Copde
Segments Segments
TINY
SMALL
MEDIUM
COMPACT
LARGE
HUGE
FLAT
one
one
one
multiple
multiple
multiple
one
one
one
multiple
one
multiple
multiple
one
Special Features
.COM files. CS and DS combined
smallest .EXE model
Uses normalized address
32 bit addressing
3.3 Instruction Types
Instruction Types
Scope
Data transfer
reg<->reg; reg<->mem
Strings
move, scan, compare strings in memory
Arithmetic
add, sub (signed or no), mul, div, BCD, ASCII
Bit manipulation
AND, OR, XOR, NOT, shift, rotate
Loops and jumps
Conditional and unconditional program jumps
Subrutine and interrupt Subrutine (far, near) and interrupt, stack control
Processor control
control flags, enable/disable interrupts,
Data size
8, 16, 32 bit
64KB
8, 16, 32 bit
8, 16, 32 bit