Restore correct 64 bit version of pop_1st_bit()

[stockfish] / src / bitcount.h

diff --git a/src/bitcount.h b/src/bitcount.h
index 12826a9f9a05472c6e48066c202b55e0eea158ea..4747afc6aa73861e7a34785833352fc905c030e4 100644 (file)
--- a/src/bitcount.h
+++ b/src/bitcount.h
@@ -22,33 +22,17 @@
 #if !defined(BITCOUNT_H_INCLUDED)
 #define BITCOUNT_H_INCLUDED
 
-#include "bitboard.h"
+// To disable POPCNT support uncomment following line. You should do it only
+// in PGO compiling to exercise the default fallback path. Don't forget to
+// re-comment the line for the final optimized compile though ;-)
+//#define DISABLE_POPCNT_SUPPORT
 
 
-// Select type of software bit count function to use
-
-#if !defined(AUTO_CONFIGURATION) || defined(IS_64BIT)
-
-//#define USE_COMPACT_ROOK_ATTACKS
-//#define USE_32BIT_ATTACKS
-#define USE_FOLDED_BITSCAN
-
-#define BITCOUNT_SWAR_64
-//#define BITCOUNT_SWAR_32
-//#define BITCOUNT_LOOP
-
-#else
-
-#define USE_32BIT_ATTACKS
-#define USE_FOLDED_BITSCAN
-#define BITCOUNT_SWAR_32
-
-#endif
-
+#include "types.h"
 
 // Select type of intrinsic bit count instruction to use
 
-#if defined(_MSC_VER) // Microsoft compiler
+#if defined(_MSC_VER) && defined(_WIN64) // Microsoft compiler
 
 #include <intrin.h>
 
@@ -78,28 +62,33 @@ inline bool cpu_has_popcnt() {
 
 inline bool cpu_has_popcnt() { return false; }
 
-#define POPCNT_INTRINSIC(x) sw_count_1s(x)
+#define POPCNT_INTRINSIC(x) count_1s(x)
 
-#endif
+#endif // cpu_has_popcnt() selection
 
 
 /// Software implementation of bit count functions
 
-#if defined(BITCOUNT_LOOP)
+#if defined(IS_64BIT)
 
-inline int sw_count_1s(Bitboard b) {
-  int r;
-  for(r = 0; b; r++, b &= b - 1);
-  return r;
+inline int count_1s(Bitboard b) {
+  b -= ((b>>1) & 0x5555555555555555ULL);
+  b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
+  b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
+  b *= 0x0101010101010101ULL;
+  return int(b >> 56);
 }
 
-inline int sw_count_1s_max_15(Bitboard b) {
-  return count_1s(b);
+inline int count_1s_max_15(Bitboard b) {
+  b -= (b>>1) & 0x5555555555555555ULL;
+  b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
+  b *= 0x1111111111111111ULL;
+  return int(b >> 60);
 }
 
-#elif defined(BITCOUNT_SWAR_32)
+#else // if !defined(IS_64BIT)
 
-inline int sw_count_1s(Bitboard b) {
+inline int count_1s(Bitboard b) {
   unsigned w = unsigned(b >> 32), v = unsigned(b);
   v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
   w -= (w >> 1) & 0x55555555;
@@ -111,7 +100,7 @@ inline int sw_count_1s(Bitboard b) {
   return int(v >> 24);
 }
 
-inline int sw_count_1s_max_15(Bitboard b) {
+inline int count_1s_max_15(Bitboard b) {
   unsigned w = unsigned(b >> 32), v = unsigned(b);
   v -= (v >> 1) & 0x55555555; // 0-2 in 2 bits
   w -= (w >> 1) & 0x55555555;
@@ -122,23 +111,6 @@ inline int sw_count_1s_max_15(Bitboard b) {
   return int(v >> 28);
 }
 
-#elif defined(BITCOUNT_SWAR_64)
-
-inline int sw_count_1s(Bitboard b) {
-  b -= ((b>>1) & 0x5555555555555555ULL);
-  b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
-  b = ((b>>4) + b) & 0x0F0F0F0F0F0F0F0FULL;
-  b *= 0x0101010101010101ULL;
-  return int(b >> 56);
-}
-
-inline int sw_count_1s_max_15(Bitboard b) {
-  b -= (b>>1) & 0x5555555555555555ULL;
-  b = ((b>>2) & 0x3333333333333333ULL) + (b & 0x3333333333333333ULL);
-  b *= 0x1111111111111111ULL;
-  return int(b >> 60);
-}
-
 #endif // BITCOUNT
 
 
@@ -149,14 +121,32 @@ inline int sw_count_1s_max_15(Bitboard b) {
 template<bool UseIntrinsic>
 inline int count_1s(Bitboard b) {
 
-  return UseIntrinsic ? POPCNT_INTRINSIC(b) : sw_count_1s(b);
+  return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s(b);
 }
 
 template<bool UseIntrinsic>
 inline int count_1s_max_15(Bitboard b) {
 
-  return UseIntrinsic ? POPCNT_INTRINSIC(b) : sw_count_1s_max_15(b);
+  return UseIntrinsic ? POPCNT_INTRINSIC(b) : count_1s_max_15(b);
 }
 
 
+// Global variable initialized at startup that is set to true if
+// CPU on which application runs supports POPCNT intrinsic. Unless
+// DISABLE_POPCNT_SUPPORT is defined.
+#if defined(DISABLE_POPCNT_SUPPORT)
+const bool CpuHasPOPCNT = false;
+#else
+const bool CpuHasPOPCNT = cpu_has_popcnt();
+#endif
+
+
+// Global variable used to print info about the use of 64 optimized
+// functions to verify that a 64bit compile has been correctly built.
+#if defined(IS_64BIT)
+const bool CpuHas64BitPath = true;
+#else
+const bool CpuHas64BitPath = false;
+#endif
+
 #endif // !defined(BITCOUNT_H_INCLUDED)