Development:Bit mask tutorial

Bit Masking Easy Reference Chart

long word	0
word	0																1
byte	0								1								2								3
nibble	0				1				2				3				4				5				6				7
2-bit	0		1		2		3		4		5		6		7		8		9		10		11		12		13		14		15
bit	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 1 Long Word, 2 Words, 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;

}