Finishing bitwise operations theory

theory/bitwise.cpp

@@ -99,9 +99,123 @@ int main(void) {
   
   Highlight position for bit of interest with a 1, mask other positions
   with 0
+
+  * set bit position(s)
+  * reset bit position(s)
+  * check bit position(s)
+  * toggle bit position(s)
   
   */
 
+  std::cout << "Section 4: Masks" << std::endl;
+
+  const unsigned char mask_bit_0 {0b00000001};
+  const unsigned char mask_bit_1 {0b00000010};
+  const unsigned char mask_bit_2 {0b00000100};
+  const unsigned char mask_bit_3 {0b00001000};
+  const unsigned char mask_bit_4 {0b00010000};
+  const unsigned char mask_bit_5 {0b00100000};
+  const unsigned char mask_bit_6 {0b01000000};
+  const unsigned char mask_bit_7 {0b10000000};
+
+  unsigned char var {0b00000000};
+
+  // Setting bits (var |= mask)
+
+  std::cout << "** Setting bits in nth position" << std::endl;
+
+  // Setting bit in position 1
+  std::cout << "Setting bit in position 1" << std::endl;
+  var |= mask_bit_1;
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl;
+
+  // Setting bit in position 5
+  std::cout << "Setting bit in position 5" << std::endl;
+  var |= mask_bit_5;
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl; 
+
+  // Resetting bit position (var &= ~(mask))
+
+  std::cout << "** Resetting bit position" << std::endl;
+
+  // Resseting bit position 5
+  // Reseting bit mask to compare with 0, because just reset if in this position the value is 1
+  var &= ~(mask_bit_5);
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << std::endl;
+
+  std::cout << "Masking multiple bits at once (examples)" << std::endl;
+  std::cout << "Set all bits" << std::endl;
+  var |= (mask_bit_0 | mask_bit_1 | mask_bit_2 | mask_bit_3 |
+         mask_bit_4 | mask_bit_5 | mask_bit_6 | mask_bit_7);
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << "Reseting bits 0,1,5,6,7" << std::endl;
+  var &= ~(mask_bit_0 | mask_bit_1 | mask_bit_5 | mask_bit_6 |
+          mask_bit_7);
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << std::endl;
+
+  // Check bit position ((var & mask) >> n_mask_position)
+  std::cout << "Checking state of 2,3 and 7" << std::endl;
+  std::cout << "Actual var: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << "bit2 is: " << ((var & mask_bit_2) >> 2) << std::endl;
+  std::cout << "bit3 is: " << ((var & mask_bit_3) >> 3) << std::endl;
+  std::cout << "bit7 is: " << ((var & mask_bit_7) >> 7) << std::endl;
+
+  // Interpreting with booleans
+
+  std::cout << "bit6 is: " << static_cast<bool>(var & mask_bit_6) << std::endl;
+
+  std::cout << std::endl;
+
+  // Toggling(change the value) bit position( var ^= n_mask_position)
+  std::cout << "Actual var: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << "Toggle bit 0" << std::endl;
+  var ^= mask_bit_0;
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << "Toggle bit 7" << std::endl;
+  var ^= mask_bit_7;
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << "Toggle multiple bits" << std::endl;
+  var ^= (mask_bit_0 | mask_bit_7 | mask_bit_1 | mask_bit_2);
+  std::cout << "Result: " << std::bitset<8>(var) << std::endl;
+
+  std::cout << std::endl;
+
+  // Colors
+  std::cout << "Extra Section: Working with colors mask" << std::endl;
+
+
+  const unsigned int red_mask {0xFF000000};
+  const unsigned int green_mask {0x00FF0000};
+  const unsigned int blue_mask {0x0000FF00};
+  const unsigned int alpha_mask {0x000000FF};
+
+  unsigned int my_color {0xAABCDE00};
+
+  // We shift to make sure the color byte of interest is in the
+  // lower index byte position so that we can interpret that as an integer
+  // which will be between 0 and 255.
+
+  // print in hex base
+  std::cout << std::hex << std::showbase << std::endl;
+
+  std::cout << "My color: " << my_color << std::endl;
+
+  std::cout << "Red is: " << ((my_color & red_mask) >> 24) << std::endl;
+  std::cout << "Green is: " << ((my_color & green_mask) >> 16) << std::endl;
+  std::cout << "Blue is: " << ((my_color & blue_mask) >> 8) << std::endl;
+  std::cout << "Alpha is: " << ((my_color & alpha_mask) >> 0) << std::endl;
+
+
+
 }