Assembly Language Programming with Linux Ubuntu

For this lab you will be using a library

cs12Lib.o

And using basic math statements to write assembly code using integer arithmetic

The README.md file tells you how to use the library

The link to this online is https://github.com/stuart-srjc/CS12-

Labs/blob/master/cs12Lib/README.md

An example is given for each of the functions, this library may grow/change over time

Using the next two slides create a math project

You will want to create a project named

math

Create a fresh project

use your own name for projectName

Go to the CS12-Libs Directory

git pull cd template ./createProject projectName cd ../projectName make ./projectName

You should see CS12 print out

Blank project file You can use this for future projects as well

The createProject will do the following

Create a directory Create a basic .asm file Create a Makefile for this project

make will build the project make clean will clean up the files

Use pico to edit the .asm file

Add

• Store the value 0x0a in rax

• Print the register

• Add 0x0a to rax

• Print the register

• Add 0x0a to rax again

• Print the register

• Your output should be what is shown on the right.

• I will review the code for the add statements

CS12 ADD

0x000000000000000A

0x0000000000000014

0x000000000000001E

Add with carry

To add with carry store the value

0xFF in AL

• Add 0x1 to al

• Add with carry 0x1 to al

• Print RAX

• You should see the line below added to your output

  0x0000000000000002

CS12

0xFF in AL

• Add 0x1 to al

• Add with carry 0x1 to al

• Print RAX

• You should see the line below added to your output

  0x0000000000000002

CS12

ADD

0x000000000000000A

0x0000000000000014

0x000000000000001E

0x0000000000000002

Increment

Increment the rax register and

print it out

CS12

ADD

0x000000000000000A

0x0000000000000014

0x000000000000001E

0x0000000000000002

0x0000000000000003

Subtract

• Add the SUB to the output

• Subtract 0xa from the rax

• register and print it

• All previous data should print out as well as shown, in subsequent slides I will not be providing the previous data, but the last slide will hold the entire expected output.

CS12

ADD

0x000000000000000A

0x0000000000000014

0x000000000000001E

0x0000000000000002

0x0000000000000003

SUB

0xFFFFFFFFFFFFFFF9

Decrement

Decrement rax

Print rax

0xFFFFFFFFFFFFFFF8

Unsigned Multiplication

• Output MUL

• Set rax to 0x80

• Multiply rax by 0xa (using rbx)

• Print the register value for RDX

• Print the register value for RAX

• Now set rax to 0x8000000001

• Multply rax by 0x8000000000

• Print RDX And RAX Note values in both registers

MUL

0x0000000000000000

0x0000000000000500

0x0000000000004000

0x0000008000000000

Signed Multiplication

• Set al to 0x8f

• Use mul to multiply

al by 0x2 (using bl)

• Print the register value for RAX

• Repeat with imul

• Note the difference between the singed and unsigned operations

MUL

0x0000000000000000

0x0000000000000500

0x0000000000004000

0x0000008000000000

0x000000000000011E

0x000000000000FF1E

Unsigned Division

Output DIV Set rax to 0xFFFA Set rdx to 0x0 Divide rdx:rax by 0xF (using rbx) Print the register value for RAX Print the register value for RDX Note values in both registers RAX is the quotient RDX is the remainder

DIV

0x0000000000001110

0x000000000000000A

Signed Division

Output DIV Set ax to -22 Divide ax by 0x5 (using bh) Print the register value for RAX Note: FE FC are ah:al FE = -2 remainder FC = -4 quotient

DIV

0x0000000000001110

0x000000000000000A

0x000000000000FEFC

What to turn in

• Turn in a screen shot of your program run

• Turn in the math.asm file that generates your output

• Your output should match the output listed below

CS12-Lib This library is needed for some of the labs for CS-12 Exported Functions printReg print the value in the RDI register example: : Data section extern printReg .data ; Code section . text global _start start: mov rdi, ex1234567890ABCD call printReg output: 1234567898abcd 00 ubuntu@ubuntu: /CS12-Labs/projectName GNU nano 2.5.3 File: projectName.asm A Data section extern printMSG extern exitNormal .data Code section .text global start start: call printMSG nov rdt, call printMSG call exitNormal Get Help Exit Write out Read FlReplace where Is K Cut TextJustify Cur Pos Go To Line AU Uncut TextT To Spell ubuntu@ubuntu:/CS12-Labs/math ubuntu@ubuntu:-/CS12-Labs/math$ ./mat CS12 ADD 0x000000000000000A 0x0000000000000014 Ox000000000000001E Ox0000000000000002 Ox0000000000000003 SUB OxFFFFFFFFFFFFFFF9 0xFFFFFFFFFFFFFF8 MUL 0x0000000000000000 0x0000000000004000 0x0000008000000000 Ox000000000000011E 0x000000000000FF1E DIV Ox0000000000001110 Ox000000000000FEFC ubuntuaubuntu:~ICS12 Labs /math CS12-Lib This library is needed for some of the labs for CS-12 Exported Functions printReg print the value in the RDI register example: : Data section extern printReg .data ; Code section . text global _start start: mov rdi, ex1234567890ABCD call printReg output: 1234567898abcd 00 ubuntu@ubuntu: /CS12-Labs/projectName GNU nano 2.5.3 File: projectName.asm A Data section extern printMSG extern exitNormal .data Code section .text global start start: call printMSG nov rdt, call printMSG call exitNormal Get Help Exit Write out Read FlReplace where Is K Cut TextJustify Cur Pos Go To Line AU Uncut TextT To Spell ubuntu@ubuntu:/CS12-Labs/math ubuntu@ubuntu:-/CS12-Labs/math$ ./mat CS12 ADD 0x000000000000000A 0x0000000000000014 Ox000000000000001E Ox0000000000000002 Ox0000000000000003 SUB OxFFFFFFFFFFFFFFF9 0xFFFFFFFFFFFFFF8 MUL 0x0000000000000000 0x0000000000004000 0x0000008000000000 Ox000000000000011E 0x000000000000FF1E DIV Ox0000000000001110 Ox000000000000FEFC ubuntuaubuntu:~ICS12 Labs /math