In this pdf I elaborate logical gates

1. BITWISE LOGICAL INSTRUCTIONS
AND | OR | NOT | XOR
Presented By Prof. Hamza Afzal

3. AND instructions in Assembly
• AND Destination, Source
• Both Operand Must be Same
Size
• Example
• AND reg, reg
• And reg, mem
• AND reg, imm
• AND mem, reg
• AND mem, imm
1 If both operands are 1 otherwise 0

4. OR instructions in Assembly
• OR Destination, Source
• Both Operand Must be Same
Size
• Example
• OR reg, reg
• OR reg, mem
• OR reg, imm
• OR mem, reg
• OR mem, imm
1 If any one of the operands are 1 otherwise 0

5. XOR instructions in Assembly
• XOR Destination, Source
• Both Operand Must be Same
Size
• Example
• XOR reg, reg
• XOR reg, mem
• XOR reg, imm
• XOR mem, reg
• XOR mem, imm
• Different  1
• Same  0

6. XOR instructions in Assembly
0 if both operands are same otherwise 1

7. NOT instructions in Assembly
• OR Destination
• Work with single operand Inverts the operand

8. MASKING OPERATIONS
Selective Bit Clearing
Selective Bit Setting
Selective Bit Inversion

9. What is Mask?
• A mask is a bit pattern that has
been defined by the
programmer, which allows
specific bits in a piece of data to
be tested or altered.
• TYPES
• Selective Bit Clearing
• Selective Bit Setting
• Selective Bit Inversion

10. Selective Bit Clearing (AND)
• It means that we want some
specific bits to be zero.
• Mask: 1111 0000
• AND al, 0×F0
• Al 10101010
• 11110000
• ---------------------
• And 10100000
F 0

11. Selective Bit Setting (OR)
• It means that we want some
specific bits to be 1 then the
mask is set by 1.
• Mask: 0000 1111
• OR al, 0×0F
• Al 10101010
• 00001111
• ---------------------
• OR 10101111
F
0

12. Selective Bit Inversion (XOR)
• It means that we want some
specific bits to be invert then the
mask is set by 1 in masking and
another retain value is set by 0.
• We want even values will be
invert
• mask: 10101010
• XOR al, mask
• Al 11010001
• 10101010
• ---------------------
• XOR 01111011
Invert 01234567