Development:Bit mask tutorial

Bit Masking Easy Reference Chart

       |-------------------------------------------------------------------------------------|
 Byte  |0              |1                    |2                      |3                      |
       |-------------------------------------------------------------------------------------|
Nibble |0      |1      |2        |3          |4          |5          |6          |7          |
       |-------------------------------------------------------------------------------------|
2 Bits |0  |1  |2  |3  |4  |5    |6    |7    |8    |9    |10   |11   |12   |13   |14   |15   |
       |-------------------------------------------------------------------------------------|
Bits   |0|1|2|3|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19|20|21|22|23|24|25|26|27|28|29|30|31|
       |-------------------------------------------------------------------------------------|

• All variables haves 4 Bytes, 8 Nibbles, 16 2Bits and/or 32 bits.
  • Byte range 0-255
  • Nibble range 0-15
  • 2Bit range 0-3
  • bit range 0 or 1

One Nibble Translated

• Binary = Decimal
  • 0000 = 0
  • 0001 = 1
  • 0010 = 2
  • 0011 = 3
  • 0100 = 4
  • 0101 = 5
  • 0110 = 6
  • 0111 = 7
  • 1000 = 8
  • 1001 = 9
  • 1010 = 10
  • 1011 = 11
  • 1100 = 12
  • 1101 = 13
  • 1110 = 14
  • 1111 = 15

• • • Note: Therefore Setting Bits 4-7 to 1 will make Nibble 1 15. Therefore Setting Bits 0-7 will make Nibble 0 & 1 15, and Byte 0 255

Linear Quest Var

• BYTE:
  • 0: Step1.
  • 1: Step2.
  • ...
  • 255: Step256.
• Nibble:
  • 0: Step1.
  • 1: Step2.
  • ...
  • 14: Step16.

Non-linear Quest Var

• BYTE: Main Quest Line
  • NIBBLE: Current-Step
    • BIT: Step
    • BIT: Step
    • BIT: Step
    • BIT: Step
  • NIBBLE: Sub-Quest
    • 0-15: Step 1-16

Dev Note: There are plans to make 64 bit quest variables.

001-1,40,36,0|script|BitMaskDebug|175 {

   mes "[Bit Mask Debug]";
   mes "\"What you wyou like to do?\"";
   menu
       "Shift Byte 1.", L_ByteShift,
       "Shift Nibble 0.", L_NibbleShift,
       "Shift Bit 4.", L_BitShift,
       "Done.", L_Close;

L_ByteShift:

   set @debugexample, ((DEBUGEXAMPLE & BYTE_1_MASK) >> BYTE_1_SHIFT);
   message strcharinfo(0), @debugexample;
   if (@debugexample == 175) 
       goto L_ByteUnset;

   mes "Byte 1 set to 175";
   set DEBUGEXAMPLE, (DEBUGEXAMPLE & ~(BYTE_1_MASK) | (175 << BYTE_1_SHIFT));
   goto L_Close;

L_ByteUnset:

   mes "Byte 1 set to 0";
   set DEBUGEXAMPLE, (DEBUGEXAMPLE & ~(BYTE_1_MASK) | (0 << BYTE_1_SHIFT));
   goto L_Close;

L_NibbleShift:

   set @debugexample, ((DEBUGEXAMPLE & NIBBLE_0_MASK) >> NIBBLE_0_SHIFT);
   message strcharinfo(0), @debugexample;
   if (@debugexample == 10) 
       goto L_NibbleUnset;

   mes "Nibble 0 set to 10";
   set DEBUGEXAMPLE, (DEBUGEXAMPLE & ~(NIBBLE_0_MASK) | (10 << NIBBLE_0_SHIFT));
   goto L_Close;

L_NibbleUnset:

   mes "Nibble 0 set to 0";
   set DEBUGEXAMPLE, (DEBUGEXAMPLE & ~(NIBBLE_0_MASK) | (0 << NIBBLE_0_SHIFT));
   goto L_Close;

L_BitShift:

   set @debugexample, ((DEBUGEXAMPLE & NIBBLE_1_MASK) >> NIBBLE_1_SHIFT);
   message strcharinfo(0), @debugexample;
   if (DEBUGEXAMPLE & (1 << 4))
       goto L_BitUnset; 

   mes "Bit 4 Set to 1";
   set DEBUGEXAMPLE, DEBUGEXAMPLE | (1 << 4);
   set DEBUGEXAMPLE, DEBUGEXAMPLE | (1 << 5);
   set DEBUGEXAMPLE, DEBUGEXAMPLE | (1 << 6);
   set DEBUGEXAMPLE, DEBUGEXAMPLE | (1 << 7);
   goto L_Close;

L_BitUnset:

   mes "Bit 4 Set to 0";
   set DEBUGEXAMPLE, DEBUGEXAMPLE &~ (1 << 4);
   set DEBUGEXAMPLE, DEBUGEXAMPLE &~ (1 << 5);
   set DEBUGEXAMPLE, DEBUGEXAMPLE &~ (1 << 6);
   set DEBUGEXAMPLE, DEBUGEXAMPLE &~ (1 << 7);
   goto L_Close;

L_Close:

   set @debugexample, 0;
   close;

OnInit:

   if (debug)
       end;
   disablenpc "BitMaskDebug";
   end;

}