Difference between revisions of "CSC270 Exercises on Assembly Language"

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* How many cycles?
 
* How many cycles?
 
* How many bytes?
 
* How many bytes?
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==Pause==
 
==Pause==
  
 
* Let's learn about ''direct addressing mode''
 
* Let's learn about ''direct addressing mode''
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* The excerpt below is taken from [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCYQFjAA&url=http%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fdownload%3Fdoi%3D10.1.1.126.6765%26rep%3Drep1%26type%3Dpdf&ei=piNyT7mpE-ru0gH_lrnLAQ&usg=AFQjCNGc-zkqp3OzNxE4Ou2FCdaLOyUEWQ&sig2=EyTqPc-9fn63o99ocK6n0w ''Introduction to 6811 Programming''] by Fred G. Martin.
  
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<center>[[Image:6811AddressingModes.png|700px]]</center>
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==Exercise 6==
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* Back to Exercise 4.  Go through each instruction and identify the different addressing modes you used for each instruction.
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==Exercise 7==
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* Analyze the program below and make it shorter and/or faster.  Your program should compute the same result as the original program.
  
 
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<source lang="asm">
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org 0
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jmp start
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a db 0
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b db 0
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c db 0
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start:  ldaa a
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inca
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        staa a
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ldaa b
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inca
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        inca
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        staa    b
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        ldaa c
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inca
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        inca
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        inca
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        staa c
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jmp    start
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</source>
 
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<code><pre>
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a      db      0 ;                                         
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b      db      0
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c      db      0
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start:  ldaa    #1 ; 86 01  2 cycles                         
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staa    a ; 97 00  3 cycles                         
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inca ; 4C    2 cycles                         
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staa    b ; 97 01  3 cycles                         
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inca ; 4C    2 cycles                         
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        staa    c ; 97 02  3 cycles                         
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jmp    start ; 7E 00 03 3 cycles                       
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        ;;                        -----  ----------                       
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        ;;                        13 bytes 18 cycles                       
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</pre></code>
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</onlydft>
 
[[Category:CSC270]][[Category:6811]][[Category:6800]][[Category:Exercises]]
 
[[Category:CSC270]][[Category:6811]][[Category:6800]][[Category:Exercises]]

Latest revision as of 09:26, 2 April 2012

--D. Thiebaut 16:20, 27 March 2012 (EDT)

Learning Assembly Through Exercises

Exercise 1

  • Write a program that uses 3 byte variables, a, b, and c. The variable are initialized before the program starts with the values 2, 5, and 0, respectively.
  • The program will add up the contents of the variable a to that of b and store the result into c. Only c will change.

Exercise 2

  • Assemble the program of Exercise 1
  • How many bytes does it contain?
  • How fast will it go from beginning to end, assuming each 6811 cycle is 1 µsecond?

Exercise 3

  • Same as Exercise 1, but for the Pentium.
  • Assuming that the Pentium runs at a clock speed of 3 GHz, how many times could the program run on the Pentium while the same program run on the 1MHz 6811?

Exercise 4

  • We want to compute Y = a + b - c + 3, where Y, a, b, and c are byte variables.
  • Write the program that performs this operation.
  • Assemble the program
  • Count the total number of cycles it will take to run, and the total number of bytes it will use up in RAM.

Exercise 5

FibonacciRabits.png
  • Write a program that computes the first 5 terms of the fibonacci sequence, assuming that your program starts with 5 variables that all zero.
  • Assemble it.
  • How many cycles?
  • How many bytes?










Pause


6811AddressingModes.png



Exercise 6

  • Back to Exercise 4. Go through each instruction and identify the different addressing modes you used for each instruction.

Exercise 7

  • Analyze the program below and make it shorter and/or faster. Your program should compute the same result as the original program.


	org	0
 	jmp	start

a	db	0
b	db	0
c	db	0

start:  ldaa	a
	inca
        staa	a
	ldaa	b
	inca
        inca
        staa    b
        ldaa	c
	inca
        inca
        inca
        staa	c
	jmp     start











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