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WRES 1201 LabThis week:

1. Project requirements

2. Revision

3. Sample code

4. Lab assignment

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Assignment

Contributes 20% of your total coursework marks.

32 bit or 16 bit.

Number of assignment: 4

Each assignment contributes 5% marks.

Each assignment must be demo in the lab

session.

Report and the written code. 2 students per group for each assignment.

1stassignment: in the end of this lab session.

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Revision

Basic Elements of Assembly Language.

Adding and Subtracting Integers example

of code

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Integer Constants

Optional leading +or sign

binary, decimal, hexadecimal, or octal digits

Common radix characters:

h hexadecimal

d decimal b binary

r encoded real

q/o - octal

Examples: 30d, 6Ah, 42, 1101b, 33q, 22o

Hexadecimalbeginning with letter must have a leading zero toprevent the assembler interpreting it as an identifier : 0A5h

If no radix:decimal

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Integer Expressions

Operators and precedence levels:

Examples:

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Character and String Constants

Enclose characterin single or double quotes

'A', "x"

ASCII character = 1 byte

Enclose stringsin single or double quotes

"ABC"

'xyz'

Each character occupies a single byte

Embedded quotes:

'Say "Goodnight," Gracie'

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Reserved Words

Reserved words(Appendix D) cannot be used as identifiers

Instruction mnemonics (MOVE, ADD, MUL)

Directives (INCLUDE)

type attributes (BYTE, WORD)

Operators (+, -) predefined symbols (@data)

Directives

command understood by the assembler not part of Intel instruction set

case insensitive

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Directives

Commandsthat are recognized / understoodand acted upon

by the assembler

Not part of the Intel instruction set

Used to declare code, data areas, select memory model, declare

procedures, etc. Not case sensitive (.data, .DATA, .Data - same)

Different assemblers have different directives

NASM != MASM, for example

Examples : .DATAidentify area of a program that contains variables

.CODEidentify area of a program that contains instructions

PROCidentify beginning of a procedure. name PROC

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Instructions

Assembled into machine codeby assembler

Executed at runtime by the CPU after the program has been

loaded into memory and started.

Member of the Intel IA-32 instruction set

Parts :

A) Label (optional)

B) Mnemonic (required)

C) Operand (required)

D) Comment (optional)

Label : Mnemonics Operand(s) ; Comment

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A) Labels

Act as place markermarks the address (offset) of codeand data

Follow identifierrules(refer slide pg 8)

Datalabel

must be unique

example: myArray

mov ax, myVariable

Codelabel

target of jump and loop instructions

example: L1:target:

mov ax,bx

jmp target

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B) Mnemonics and Operands

Instruction Mnemonics is a short word that identifies the operation

carried out by an instruction. (useful name)

Examples :

MOV move (assign one value to another)

ADD add two values

SUB subtract one value from another

MUL multiply two values

INC increment

DEC decrement

JMP jump to a new location

CALL call a procedure

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C) Operands

An assembly language can have between zero to three

operands

Types of operand :

constant (immediate value)

96, 2005h, 101011010b

constant expression

2+4

register

EAX, EBX, AX, AH

memory(data label)

count

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.. C) Operands

Examples assembly language instructions with various

number of operands :

No operand

stc ; set carry flag

one operand

inc ax ; add 1 to AX

two operand

mov count, bx ; move BX to count

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D) Comments

Comments are good.

explain the program's purpose

when it was written, and by whom

revision information

tricky coding techniques

application-specific explanations

Single-line comments

begin with semicolon (;)

Ex : ; add BX to AX

Multi-line comments

begin with COMMENT directive and a programmer-chosen character

end with the same programmer-chosen character Ex :

COMMENT !

This is a comment

This line is also a comment

Comment lagi dan lagi dan lagi.

Lepas ni habis ekk

!

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Instruction Format Examples

No operands

stc ; set Carry flag

One operand

inc eax ; register inc myByte ; memory

Two operands

add ebx,ecx ; register, register

sub myByte,25 ; memory, constant

add eax,36 * 25 ; register, constant expression

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TITLE Kira Baki Biasiswa (pokai.asm)

;Program Description:

; Author:

; Date Created:

; Last Modification Date:

INCLUDE Irvine32.inc

.data

(insert variables here)

val1 dword 10000h

.code

main PROC

(insert executable instructions here)

mov ax,@data ; initialize DS

exit ; exit to operating system

main ENDP

(insert additional procedures here)

END main

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Example: Adding and Subtracting

Integers

TITLEAdd and Subtract (AddSub.asm)

; This program adds and subtracts 32-bit integers.

INCLUDE Irvine32.inc

.code

main PROC

mov eax,10000h ; EAX = 10000h

add eax,40000h ; EAX = 50000h

sub eax,20000h ; EAX = 30000h

call DumpRegs ; display registers

exit

main ENDP

END main

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mov eax,10000h

0010 0000EAX 10000 h

add eax,40000h

0050 0000EAX10000 h + 40000 h

= 50000 h

sub eax,10000h

0030 0000EAX50000 h 20000 h

= 30000 h

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Example Output

Program output, showing registers and flags:

EAX=00030000 EBX=7FFDF000 ECX=00000101 EDX=FFFFFFFF

ESI=00000000 EDI=00000000 EBP=0012FFF0 ESP=0012FFC4

EIP=00401024 EFL=00000206 CF=0 SF=0 ZF=0 OF=0

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Suggested Coding Standards (1 of 2)

Some approaches to capitalization

capitalize nothing

capitalize everything

capitalize all reserved words, including instruction mnemonics

(MOV)and register names (AX,EAX) capitalize only directives(.data)and operators(+,-)

Other suggestions

descriptive identifier names spaces surrounding arithmetic operators

blank lines between procedures

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Suggested Coding Standards (2 of 2)

Indentation and spacing

code anddata labelsno indentation

executable instructionsindent 4-5 spaces

comments: begin at column 40-45, aligned

vertically

1-3 spaces between instruction and its

operands ex: mov ax,bx

1-2 blank lines between procedures

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Program Template

TITLE Program Template (Template.asm)

; Program Description:

; Author:

; Creation Date:

; Revisions:

; Date: Modified by:

INCLUDE Irvine32.inc

.data

; (insert variables here)

.code

main PROC ; (insert executable instructions here)

exit

main ENDP

; (insert additional procedures here)

END main

Instruction: please

customize as needed

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Assignment 1

Write a program MASM assembly langguage to have the input

and output as follows:

Input:

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Assignment 1

Output:

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.Assignment 1

Due date: 2 weeks from now.

18 March 2014.

Demo in the lab. Write a simple report with a code of the

program.

2 students per group.