Slide 11.5: AND instruction

Slide 11.4: Boolean instructions
Slide 11.6: OR instruction
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AND Instruction (Cont.)

The operands can be 8, 16, or 32 bits, and they must be the same size. For each matching bit in the two operands, the output bit is 1 when both of the input bits are 1; otherwise, it is 0. The table on the right describes the boolean expression .

`X`	`Y`	`X AND Y`
0	0	0
0	1	0
1	0	0
1	1	1

Code I: If we compare the ASCII codes of capital and lowercase , it becomes clear that only bit 5 is different:
```
    0 1 1 0 0 0 0 1 = 61h ('a')
    0 1 0 0 0 0 0 1 = 41h ('A')
```
The rest of the alphabetic characters have the same relationship. If we any character with binary, all bits are unchanged except for bit 5, which is cleared.

Code II: To convert an integer digit into an ASCII digit, you must set bits 4 and 5. If, for example, , you can it with to convert it into the ASCII code for the digit 5 ().

Code I: Lowercase 🡆 Uppercase

Code II: Integer 🡆 ASCII

 INCLUDE Irvine32.inc
 .data
  p1  BYTE  "Enter a letter: ", 0
  p2  BYTE  "The letter is ", 0
  buffer  BYTE  64 DUP(0)
 .code
 main PROC
  mov   edx, OFFSET p1
  call  WriteString
  mov   edx, OFFSET buffer
  mov   ecx, SIZEOF buffer
  call  ReadString
  mov   ecx, eax
  mov   esi, OFFSET buffer
 L1:
  cmp   BYTE PTR [esi], 'a'
  jl    L2
  cmp   BYTE PTR [esi], 'z'
  jg    L2
  
  
  
  
  
    
    
    


    
    
    
   L2:
  inc   esi
  loop  L1
  mov   edx, OFFSET p2
  call  WriteString
  mov   edx, OFFSET buffer
  call  WriteString
  exit
 main ENDP
 END main

 INCLUDE Irvine32.inc
 .data 
  p1  BYTE  "Enter a digit: ", 0
  p2  BYTE  "The ASCII is '", 0
  p3  BYTE  "' or ", 0
 .code
 main PROC
  call  Clrscr
  mov   edx, OFFSET p1
  call  WriteString
  call  ReadInt
  
  
  
  
  
   
   
   


   
   
   
    mov   edx, OFFSET p2
  call  WriteString
  call  WriteChar
  mov   edx, OFFSET p3
  call  WriteString
  call  WriteInt
  exit
 main ENDP
 END main

An Execution Example

Enter a letter: e
The letter is E

Enter a digit: 7
The ASCII is '7' or +55

^†The italic white text with navy background is entered by users.

“I’m not arguing, I’m just explaining why I’m right.”
― Unknown