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#include "tak.h"
// Be sure not to set higher bits in colour than LSB
void set_stone(board_t board, bit_board_t *capstand,
const uint8_t location,
const uint8_t colour,
const enum STONE_VARIANT stone) {
board[location] = (STONE_IS_CAPSTAND(stone) ? CELL_MASK_CAPSTAND : 0x0000)
| CELL_COUNT_INC | colour;
if (stone == STONE_CAPSTONE) BITBOARD_SET(*capstand, location);
}
// This can overflow, checks are elsewhere
void push_cells_stack(board_t board, bit_board_t *capstand,
const uint8_t location, const uint8_t count,
const uint8_t colours,
const enum STONE_VARIANT top_stone) {
if (top_stone == STONE_CAPSTONE) BITBOARD_RST(*capstand, location);
const cell_t cell = board[location];
const uint8_t new_count = CELL_GET_COUNT(cell) + count;
const uint8_t new_stack = (CELL_GET_STACK(cell) << count) | colours;
board[location] = (STONE_IS_CAPSTAND(top_stone) ? CELL_MASK_CAPSTAND : 0x0000)
| ((new_count > 0xA) ? 0xA : new_count)
| (new_stack & CELL_MASK_STACK);
}
// Calling this with count = 0 is destructive
void drop_cells_stack(board_t board, bit_board_t *capstand,
const uint8_t location, const uint8_t count) {
// NOTE: We always clear the bitboard and capstand flags as it's not
// possible that those stones are underneath anything.
BITBOARD_RST(*capstand, location);
const uint8_t cur_count = CELL_GET_COUNT(board[location]);
if (count >= cur_count) {
board[location] = CELL_EMPTY_VALUE;
} else {
board[location] = ((cur_count - count) << CELL_COUNT_SHIFT)
| (CELL_GET_STACK(board[location]) >> count);
}
}
enum ACTION_RESULT try_place_stone(board_t board, bit_board_t *capstand,
const uint8_t location, const uint8_t colour,
const enum STONE_VARIANT stone)
{
// Can't place on an occupied square
if (CELL_IS_EMPTY(board[location])) {
set_stone(board, capstand, location, colour, stone);
return A_OK;
} else {
return A_ILLEGAL;
}
}
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