From b1d677fa134741527669b93a77810cf01dd34de5 Mon Sep 17 00:00:00 2001
From: tslil clingman <tslil@posteo.de>
Date: Sun, 17 Jan 2021 23:16:09 -0500
Subject: Inlined placements, should be faster

---
 include/ct1986.c | 71 ++++++++++++++++++++++++++++++++++++++++----------------
 include/tak.c    |  1 -
 include/tak.h    |  9 +++----
 3 files changed, 56 insertions(+), 25 deletions(-)

(limited to 'include')

diff --git a/include/ct1986.c b/include/ct1986.c
index 5e1c0fc..9289d2f 100644
--- a/include/ct1986.c
+++ b/include/ct1986.c
@@ -170,8 +170,14 @@ ct1986_minimax(const uint8_t cur_depth, const uint8_t max_depth,
 							 const uint8_t min, float alpha, float beta) {
 
 	enum E_RESULT r;
-	const uint8_t white_count_backup = white_count,
-		black_count_backup = black_count;
+	const uint8_t black = (ply & 1),
+		material = (black) ? black_count : white_count;
+
+	uint8_t cap = 0, flat = material & 127, standing = 0;
+	if (ply > 2) {
+		if (material & 128) cap = 1;
+		if (material & 127) standing = 1;
+	}
 
 	// 1.0 is a `certain' black win, -1.0 is a `certain' white win.
 	float optimal = (min) ? infty : -infty;
@@ -261,30 +267,55 @@ ct1986_minimax(const uint8_t cur_depth, const uint8_t max_depth,
 					}
 				}
 			} else if (count == 0) {
-				// Empty square, try the three placements. Again, looping
-				// through enums, sigh.
-				for (enum STONE_VARIANT stone = STONE_FLAT;
-						 stone <= STONE_CAPSTONE; stone++) {
-					// try_place will never check for winning, and we don't do
-					// that either here
-					r = try_place(loc, current_colour, stone);
-					// Legal placement, evaluate it
-					if (r == ACT_OK) {
-						// First check for wins, if we're at the bottom
-						// evaluate, otherwise recurse
-						WIN_EVALUATE_OR_RECURSE({
+				// Empty square, try the three placements.
+
+				if (flat) {
+					// Generate the placement
+					if (black) black_count--;
+					else white_count--;
+					colours[loc] = current_colour;
+					celldat[loc] = NUM_INC | STONE_FLAT;
+					WIN_EVALUATE_OR_RECURSE({
 								// If we did update the optimal value, store
-								// this move
-								generate_place(loc, stone, ct1986_ptn);
+								generate_place(loc, STONE_FLAT, ct1986_ptn);
+							});
+					// Reset the state
+					celldat[loc] = 0;
+					if (black) black_count++;
+					else white_count++;
+					// Prune
+					if (alpha >= beta) return optimal;
+
+					// Do the same for walls, can't happen without flats
+					if (standing) {
+						if (black) black_count--;
+						else white_count--;
+						colours[loc] = current_colour;
+						celldat[loc] = NUM_INC | STONE_STANDING;
+						WIN_EVALUATE_OR_RECURSE({
+								generate_place(loc, STONE_STANDING, ct1986_ptn);
 							});
-						// Reset the state
 						celldat[loc] = 0;
-						white_count = white_count_backup;
-						black_count = black_count_backup;
-						// Prune
+						if (black) black_count++;
+						else white_count++;
 						if (alpha >= beta) return optimal;
 					}
 				}
+
+				// and for caps
+				if (cap) {
+					if (black) black_count &= 127;
+					else white_count &= 127;
+					colours[loc] = current_colour;
+					celldat[loc] = NUM_INC | STONE_STANDING;
+					WIN_EVALUATE_OR_RECURSE({
+							generate_place(loc, STONE_STANDING, ct1986_ptn);
+						});
+					celldat[loc] = 0;
+					if (black) black_count |= 128;
+					else white_count |= 128;
+					if (alpha >= beta) return optimal;
+				}
 			}
 			ct1986_display_progress(cur_depth);
 		}
diff --git a/include/tak.c b/include/tak.c
index ef4fc7d..3d3ba0f 100644
--- a/include/tak.c
+++ b/include/tak.c
@@ -15,7 +15,6 @@ uint8_t white_count, black_count, ply;
 // Helpers
 // ===================================================================
 
-#define NUM_INC       (0x1<<NUM_SHIFT) // 0b00010000
 #define NUM_MASK      (0xF<<NUM_SHIFT) // 0b11110000
 #define DFS_MASK      0b00001100
 #define NOT_DFS_MASK  0b11110011
diff --git a/include/tak.h b/include/tak.h
index ad0b994..0a97c2d 100644
--- a/include/tak.h
+++ b/include/tak.h
@@ -19,10 +19,11 @@ enum WIN_TYPE       { WIN_DRAW,
 typedef uint8_t data_t;
 typedef uint16_t colour_stack_t;
 
-#define NUM_SHIFT  4
-#define STONE_MASK 0b00000011
-#define STONE_AT(l) (celldat[(l)] & STONE_MASK)
-#define COUNT_AT(l) (celldat[(l)] >> NUM_SHIFT)
+#define NUM_SHIFT           4
+#define NUM_INC             (0x1<<NUM_SHIFT) // 0b00010000
+#define STONE_MASK          0b00000011
+#define STONE_AT(l)         (celldat[(l)] & STONE_MASK)
+#define COUNT_AT(l)         (celldat[(l)] >> NUM_SHIFT)
 #define THE_COORDS(col,row) ((col)+(row)*board_size)
 
 extern enum WIN_TYPE won;
-- 
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