Difference between revisions of "CSC231 Homwork 2 Solution 2010"

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__TOC__
 
__TOC__
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<onlysmith>
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=Number Systems=
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<code><pre>
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Angela Zhu
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231a-ab
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hw2b.txt
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CSC 231
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Sept. 29, 2010
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Decimal: 135
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Hexadecimal: 87
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Binary: 1000 0111
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Decimal: 1001
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Hexadecimal: 3E9
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Binary: 0011 1110 1001
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Decimal: 255
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Hexadecimal: FF
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Binary: 1111 1111
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Decimal: 2561
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Hexadecimal: A01
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Binary: 1010 0000 0001
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Decimal: 65535
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Hexadecimal: FFFF
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Binary: 1111 1111 1111 1111
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 +
Decimal: 63640
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Hexadecimal: F898
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Binary: 1111 1000 1001 1000
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Decimal: 31
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Hexadecimal: 1F
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Binary: 1 1111
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Decimal: 2290649224
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Hexadecimal: 88888888
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Binary: 1000 1000 1000 1000 1000 1000 1000 1000
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</pre></code>
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=Logic Design=
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* To test the validity of boolean function, a simple Python program can be of great help.
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<code><pre>
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#! /bin/env python
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# truthtable.py
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# D. Thiebaut
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# how a simple python program can generate the
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# truth table of a boolean function
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#
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def xor( a, b ):
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    return a and (not b) or (not a ) and b
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def candidate( b3, b2, b1, b0 ):
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    return b2 and b3 and not (b0 and b1) \
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        or b0 and b1 and not (b2 and b3) \
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        or xor( b0, b1) and xor( b2, b3 )
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def main():
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    print "  a  b  c  d |  f  "
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    print "------------+------"
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    for a in [ 0, 1 ]:
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        for b in [ 0, 1 ]:
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            for c in [ 0, 1 ]:
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                for d in [ 0, 1 ]:
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                    x = candidate( a, b, c, d )
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                    print "%3d%3d%3d%3d  |%3d" % \
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                        ( a, b, c, d, x )
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main()
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</pre></code>
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* [[media:CSC231_hw2_solution_Part_1_2010.pdf | Solution (pdf)]]
  
 
=Mystery Program=
 
=Mystery Program=
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* The program prints a quote attributed to Kurt Cobain: "Practice makes perfect... but nobody's perfect... so why practice?"
  
 
<code><pre>
 
<code><pre>
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</pre></code>
 
</pre></code>
  
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==Testing the Mystery Program==
 
<br />
 
<br />
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* To test the programs, the hexadecimal dump of the object file of the original program was compared to the hexadecimal dump of the object file of your version.
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* Assume that hw2_mystery.solution.asm is the orginal that you have to recreate, and assume that hw2c.asm is your program:
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nasm -f elf hw2c.asm
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hexdump -C hw2c.o | tail -190 | head -40 > hw2c.lst
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nasm -f elf hw2_mystery.solution.asm
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hexdump -C hw2_mystery.solution.o | tail -190 | head -40 > hw2_mystery.solution.lst
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diff -y hw2_mystery.solution.lst  hw2c.lst
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* The output is shown below.  When only 1 vertical bar separates the two columns, then the program on the left matches the program on the right.  When double vertical bars appear, there is a difference between the two programs.  Visual inspection will indicate where the problem bytes are...
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000001f0  04 00 00 00 08 00 00 00  00 00 00 00 00 00 00 00  | 000001f0  04 00 00 00 08 00 00 00  00 00 00 00 00 00 00 00  |
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00000200  20 6d 61 6b 65 73 20 70  65 72 66 65 63 74 2e 2e  | 00000200  20 6d 61 6b 65 73 20 70  65 72 66 65 63 74 2e 2e  |
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00000210  2e 70 72 61 63 74 69 63  65 62 75 74 20 6e 6f 62  | 00000210  2e 70 72 61 63 74 69 63  65 62 75 74 20 6e 6f 62  |
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00000220  6f 64 79 27 73 20 73 6f  20 77 68 79 20 3f 0a 0a  | 00000220  6f 64 79 27 73 20 73 6f  20 77 68 79 20 3f 0a 0a  |
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00000230  b8 04 00 00 00 bb 01 00  00 00 b9 11 00 00 00 ba  | 00000230  b8 04 00 00 00 bb 01 00  00 00 b9 11 00 00 00 ba  |
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00000240  08 00 00 00 cd 80 b8 ff  ff ff ff b8 04 00 00 00  | | 00000240  08 00 00 00 cd 80 b8 04  00 00 00 bb 01 00 00 00  |
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00000250  bb 01 00 00 00 b9 07 00  00 00 b9 00 00 00 00 ba  | | 00000250  b9 07 00 00 00 b9 00 00  00 00 ba 10 00 00 00 cd  |
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00000260  07 00 00 00 cd 80 ba 11  00 00 00 b8 01 00 00 00  | | 00000260  80 ba 11 00 00 00 b8 01  00 00 00 b8 04 00 00 00  |
 +
00000270  b8 04 00 00 00 bb 01 00  00 00 b9 07 00 00 00 ba  | | 00000270  bb 01 00 00 00 b9 07 00  00 00 ba 0a 00 00 00 cd  |
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00000280  0a 00 00 00 cd 80 b8 04  00 00 00 bb 01 00 00 00  | | 00000280  80 b8 04 00 00 00 bb 01  00 00 00 b9 19 00 00 00  |
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00000290  b9 19 00 00 00 ba 0d 00  00 00 cd 80 b8 04 00 00  | | 00000290  ba 0d 00 00 00 cd 80 b8  04 00 00 00 bb 01 00 00  |
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000002a0  00 bb 01 00 00 00 b9 06  00 00 00 ba 0a 00 00 00  | | 000002a0  00 b9 06 00 00 00 ba 0a  00 00 00 41 cd 80 b8 04  |
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000002b0  41 cd 80 b8 04 00 00 00  bb 01 00 00 00 b9 24 00  | | 000002b0  00 00 00 bb 01 00 00 00  b9 24 00 00 00 41 ba 07  |
 +
000002c0  00 00 41 ba 07 00 00 00  41 cd 80 b8 04 00 00 00  | | 000002c0  00 00 00 41 cd 80 b8 04  00 00 00 bb 01 00 00 00  |
 +
000002d0  bb 01 00 00 00 b9 11 00  00 00 ba 08 00 00 00 cd  | | 000002d0  b9 0e 00 00 00 ba 0b 00  00 00 cd 80 b8 04 00 00  |
 +
000002e0  80 b8 04 00 00 00 bb 01  00 00 00 b9 2d 00 00 00  | | 000002e0  00 bb 01 00 00 00 b9 2d  00 00 00 ba 03 00 00 00  |
 +
000002f0  ba 03 00 00 00 cd 80 b8  01 00 00 00 bb 00 00 00  | | 000002f0  cd 80 b8 01 00 00 00 bb  00 00 00 00 cd 80 00 00  |
 +
00000300  00 cd 80 00 00 00 00 00  00 00 00 00 00 00 00 00  | | 00000300  00 54 68 65 20 4e 65 74  77 69 64 65 20 41 73 73  |
 +
 
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</onlysmith>
 
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Latest revision as of 12:21, 14 December 2010

--D. Thiebaut 21:35, 6 October 2010 (UTC)



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