Logical instruction(AND, OR, XOR, NOT) with example. Shift instruction Converting ASCII code Rotate instruction

1. W E L C O M E T O O U R
P R E S E N TAT I O N

2. Logical, Shift, and Rotate Instruction

3. CONTENT:
• Logical instruction(AND, OR, XOR, NOT) with example.
• Shift instruction
• Rotate instruction
• Converting ASCII code

4. LOGICAL INSTRUCTION:
Logical table of and, or, xor, and not gate:
a b a AND b a OR b a XOR b
0 0 0 0 0
0 1 0 1 1
1 0 0 1 1
1 1 1 1 0
a NOT a
0 1
1 0

5. LOGICAL AND:
1 0 1 0 1 0 1 0
1 1 1 1 0 0 0 0
00 0 001 0
0
1
1
0
0
1
0 1 1 0 1 1 1 0
1 0 1 1 0 0 1 1
11 1 111 1
0
1
1
0
1
1
ZF:
SF:
PF:
CF:
OF:
ZF:
SF:
PF:
CF:
OF:

6. LOGICAL OR:
1 0 1 0 1 0 1 0
1 1 0 1 0 0 0 1
11 0 111 1
0
1
0
0
0
1
0 1 1 0 1 0 1 0
1 0 1 1 0 0 1 1
00 0 100 0
0
0
0
0
1
1
ZF:
SF:
PF:
CF:
OF:
ZF:
SF:
PF:
CF:
OF:

7. LOGICAL XOR:
1 0 1 0 1 0 1 0
1 1 1 1 0 0 1 1
11 0 010 1
0
0
1
0
1
0
0 1 1 0 1 0 1 1
1 0 1 1 0 1 1 1
01 1 011 1
0
1
1
0
1
0
ZF:
SF:
PF:
CF:
OF:
ZF:
SF:
PF:
CF:
OF:

8. LOGICAL NOT:
1 0 1 0 1 0 1 0
11 1 000 1 0
1 1 0 0 1 1 1 0
11 0 000 0 1
0
0
1
0
1
0
0
0
0
1
ZF:
SF:
PF:
CF:
OF:
ZF:
SF:
PF:
CF:
OF:

9. AND, OR INSTRUCTION EXAMPLE:
Example-1: Clear the sign bit of AL while leaving the other bits unchanged
Solution: Use the AND instruction with 01111111b=7FH as the mask. Thus,
AND AL,7FH
Example-2: Set the most significant and least significant bits of AL while
preserving the other bits.
Solution: Use the QR instruction with 10000001b = 81h as the mask .Thus ,
OR AL , 81h

10. CONVERTING:
• Converting an ASCII Digit to a Number:
• Converting a Lowercase to a Uppercase:
• Clearing a register:
For example ,if the “5” key is pressed, AL gets 35h instead of 5.to get 5 in
AL ,we could do this..
SUB AL , 30h
SUB DL,20h
We already know two ways to clear a resister. For example, to clear AX we
could execute..
MOV AX,0 or SUB AX ,AX

11. SHIFT INSTRUCTION:
• SHL and
SAL
• SHR
• SAR
ROTATE INSTRUCTION:
• ROL
• ROR
• RCL
• RCR

12. SHIFT INSTRUCTION: SHL AND SAL
• The SHL (shift left ) instruction shifts the bits in the destination to the left.
• A 0 is shifted into the right most bit position and the msb is shifted into CF.
0 1 1 0 0 1 0 1
00100 1
0000 0
0
CF
CF
11 1-S
2-S1111
0
0

13. SHIFT INSTRUCTION: SHR
• The instruction SHR(shift right) performs right shift on the destination operand.
• A 0 is shifted into the msb position ,and the rightmost bit is shifted into CF.
0 1 1 0 0 1 0 1
00000
000 00 0
1 1 1 1
1 1 1
1-S
2-S
CF
CF
0
0

14. SHIFT INSTRUCTION: SAR
• The SAR instruction (shift arithmetic right) operates like SHR, with one
difference: the msb retains its original value.
0 1 1 0 0 1 0 1
00000
000 00 0
1 1 1 1
1 1 1
1-S
2-S
CF
CF

15. ROTATE INSTRUCTION: ROL
• The instruction ROL (rotate left )shifts bits to the left .The msb is shifted into
the rightmost bit . The CF also gets the bit shifted out of the msb .
0 1 1 0 0 1 0 1
000 1
1000
0 1111
11111
CF
CF
1-S
2-S

16. ROTATE INSTRUCTION: ROR
• The instruction ROR (rotate right ) works just like ROL , except that the bits are
rotate to the right .The rightmost bit is shifted into the msb , and also into The CF.
0 1 1 0 0 1 0 1
00000
000 01 0
1 1 1 1
1 1 1
1-S
2-S
CF
CF

17. ROTATE INSTRUCTION: RCL
0 1 1 0 0 1 0 1
000 0
1000
1111
0111
1
0
• The instruction RCL (Rotate through carry left ) shifts the bits of the
destination to the left. The msb is shifted
into the CF, and the previous value of CF is shifted into the rightmost bit.
1-S
2-S

18. ROTATE INSTRUCTION: RCR
0 1 1 0 0 1 0 1
0000
00 00
1 1 1
1 1 1
1-S
2-S
0
1
1
1
The instruction RCR( Rotate through carry right) works just like RCL,
except that the bits are rotated to the right.
CF

19. THANK YOU.