How can I access to each bit in an integer type or byte? For example, suppose that we want to set the 2nd bit of a byte to 1 and first bit to zero. How can I do so? Thanks

: How can I access to each bit in an integer type or byte? For example, suppose that we want to set the 2nd bit of a byte to 1 and first bit to zero. How can I do so? Thanks
:
The quickest way is to use the logical AND, OR, XOR. OR is then used as an addition, AND as a subtraction, and XOR as a switch. Each bit is represented by its decimal code:

Bit Code
1   $01 // Hexidecimal numbers
2   $02
3   $04
4   $08
5   $10
6   $20
7   $40
8   $80

To access a single bit use the AND:

  i := $55 and $01; // i contains least significant bit

To set a specific bit use the OR:

  i := i or $02; // i second least significant bit is set

Switching a bit:

  i := i xor $01; // the least significant bit either cleared if set
                  // or set if it was cleared

To subtract a bit, use AND with the complement bit mask. The complement bit mask is all bits set, except the ones you want to clear.

  i := i and ($FF-$08); // removes the 4th bit