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Chess - Programming - Magic BitBoards - Calculate Magic Numbers

To start off, the following functions are needed:

uint64_t blockermask_rook   (int square);
uint64_t blockermask_bishop (int square);
uint64_t moveboard_rook     (int square, uint64_t blockerboard);
uint64_t moveboard_bishop   (int square, uint64_t blockerboard);
uint64_t blockerboard       (int index, uint64_t blockermask);

NOTE: These functions do not need to be particularly fast, because they will only be used when looking for magic numbers; and once at program startup before the magic numbers are used.

Therefore any technique can be used in these functions.

/* Example, Rook on e4:
 *  
 *    The blocker mask        A blocker board         The move board
 *    0 0 0 0 0 0 0 0         0 0 0 0 0 0 0 0         0 0 0 0 0 0 0 0 
 *    0 0 0 0 1 0 0 0         0 0 0 0 1 0 0 0         0 0 0 0 0 0 0 0 
 *    0 0 0 0 1 0 0 0         0 0 0 0 0 0 0 0         0 0 0 0 0 0 0 0 
 *    0 0 0 0 1 0 0 0         0 0 0 0 1 0 0 0         0 0 0 0 1 0 0 0 
 *    0 1 1 1 0 1 1 0         0 1 1 0 0 0 0 0         0 0 1 1 0 1 1 1 
 *    0 0 0 0 1 0 0 0         0 0 0 0 0 0 0 0         0 0 0 0 1 0 0 0 
 *    0 0 0 0 1 0 0 0         0 0 0 0 1 0 0 0         0 0 0 0 1 0 0 0 
 *    0 0 0 0 0 0 0 0         0 0 0 0 0 0 0 0         0 0 0 0 0 0 0 0 
 */

The Blocker Mask is all of the squares that can be occupied and block a piece from moving further.

The edge squares do not need to be a part of that, because the piece cannot move further past that square anyway.
The number of 1s in this BitBoard determine how large of a lookup table is needed for this piece & square combination.
In this case, there are 10 ones, so there are 2^10 (1024) possible permutations of pieces that can block an e4 rook.

The Blocker Board is one of these permutations.

In this example, there are pieces on b4, c4, e2, e5, and e7.
These are enemy and friendly pieces.
A Blocker Board is always a subset of the blocker mask (it need not show pieces on other squares.
- blockers = occupancy & blockermask.

The Move Board is the resulting available moves for your piece, for a given Blocker Board.

This includes possible captures for this piece.
- This also includes capturing own pieces (but these can easily be removed by doing an AND with a NOT of own piece locations).