Chapter 2.1, Problem 2.13PP

Program Plan Intro

Bit-level operations in C:

• One important characteristic of “C” is supporting bitwise Boolean operation.
• The symbols used in “C” is same as the Boolean operation such are “~”, “&”, “|” and “^”.
  • Encode logical operations for “~”, “&”, “|” and “^” is “NOT”, “AND”, “OR”, and “EXCLUSIVE-OR” respectively.
  • These can be applied to any “integral” data type.
  • Implementing bit set and bit clear operations in “C” bit-level operations by using “bis” and “bic” instructions respectively.
    • User can implement the function of bitwise operations such as “|” and “^” by using “bis” and “bic” instructions.
      • These both instructions take a data word “x” and a mask word “m”.

Example:

The example for applying Boolean operation in integral data type is shown below:

C Expression	Binary expression	Binary result	Hexadecimal result
~0x32	~[0011 0010]	[1100 1101]	0xCD
0x32 & 0x46	[0011 0010]&   [0100 0110]	[0000 0010]	0x02
0x12 | 0x26	[0001 0010]| [0010 0110]	[0011 0110]	0x36

Table for “~” Boolean operation:

The “~” operation means change the bit “1” to “0” and change the bit “0” to “1”.

• It is also called as “NOT” operation.

~
0	1
1	0

Table for “&”Boolean operation:

This Boolean operation is used to “AND” the value of two bits vectors.

&	0	1
0	0	0
1	0	1

Table for “|”Boolean operation:

This Boolean operation is used to “OR” the value of two bits vectors.

|	0	1
0	0	1
1	1	1

Table for “^”Boolean operation:

This Boolean operation is used to “EXCLUSIVE-OR” of two bits vectors.

^	0	1
0	0	1
1	1	0