CODEWITHSUNDEEP
assembly
hero
hero

Reputation: 1

How to solve this logic operation? (homework)

The teacher gave us this question and I couldn't answer it and I hope to get here some help.

Perform the following logic operation:
1- AB5D AND CD5F
2- DD1D XOR B159

And I want to know the step that I should follow to find the right answer.

Upvotes: 0

Views: 151

Answers (3)

Sdaz MacSkibbons
Sdaz MacSkibbons

Reputation: 28676

Convert the individual hex characters to binary, put them over one another, and for each column, if both are 1, the result will be one; in all other cases, the result will be zero. Write this down below the two other binary strings. Then, when you have done this for all digits, convert it back to hex.

Example:

A = 1010
C = 1100
    ----
    1000 = 8

There is your first digit of ANDing AB5D and CD5F. Keep doing it like that, and you'll get it.

The XOR operation gives a 1 where EITHER one or the other digit is 1, but not both.

It'd be worthwhile to brush up on all your bitwise operations, as well; they can all be done the same way.

Upvotes: 2

shybovycha
shybovycha

Reputation: 12245

0xAB5D AND 0xCD5F = 0x895D

0xDD1D XOR 0xB159 = 06C44

Use 'calc' in windows or 'gnome-calculator' in GNOME linux or just Pyrhon / Ruby it.

UPD: if you wanna do this on the paper, follow next few easy steps:

  • convert your numbers to binary (for ex. 0xAB5D == 1010101101011101; 0xCD5F == 1100110101011111)
  • perform bitwise operation on those two binaries (1010101101011101 AND 1100110101011111 = 1000100101011101)
  • convert the result to hex or decimal

Upvotes: 0

André Costa
André Costa

Reputation: 240

The members are in hexadecimal (AB5D, CD5F, ...), so it's easier if you transform them in binary before. You can use this table:

0 = 0000  4 = 0100  8 = 1000  C = 1100
1 = 0001  5 = 0101  9 = 1001  D = 1101
2 = 0010  6 = 0110  A = 1010  E = 1110
3 = 0011  7 = 0111  B = 1011  F = 1111

So, AB5D is 1010101101011101.

And then you apply the bitwise operations. It means the result of, for example, A XOR 3 is:

A XOR 3 =
1010 XOR 0011 =
1001 =
9 (see conversion table)

Upvotes: 3

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