Revert _BitScanForward64 support

[stockfish] / src / bitcount.h

diff --git a/src/bitcount.h b/src/bitcount.h
index 871247abcf4be72b16df1def8d04f97a6e6d8f52..d57b3f407339d9d2c311f9cf1a1ac12f7fbb8a94 100644 (file)
--- a/src/bitcount.h
+++ b/src/bitcount.h
@@ -66,7 +66,6 @@ inline bool cpu_has_popcnt() {
 }
 
 #define POPCNT_INTRINSIC(x) __popcnt64(x)
-#define BITSCAN_INTRINSIC(idx, x) _BitScanForward64(idx, x)
 
 #elif defined(__INTEL_COMPILER) && (defined(__x86_64) || defined(_M_X64)) // Intel compiler
 
@@ -80,14 +79,12 @@ inline bool cpu_has_popcnt() {
 }
 
 #define POPCNT_INTRINSIC(x) _mm_popcnt_u64(x)
-#define BITSCAN_INTRINSIC(idx, x) _BitScanForward64(idx, x)
 
 #else // Safe fallback for unsupported compilers
 
 inline bool cpu_has_popcnt() { return false; }
 
 #define POPCNT_INTRINSIC(x) count_1s(x)
-#define BITSCAN_INTRINSIC(idx, x) count_1s(x) // dummy
 
 #endif
 
@@ -168,27 +165,6 @@ inline int count_1s_max_15(Bitboard b) {
 }
 
 
-/// pop_1st_bit() finds and clears the least significant nonzero bit in a
-/// nonzero bitboard. If template parameter is true an intrinsic is called,
-/// otherwise we fallback on a software implementation.
-
-template<bool UseIntrinsic>
-inline Square pop_1st_bit(Bitboard *b) {
-
-  return pop_1st_bit(b);
-}
-
-template<>
-inline Square pop_1st_bit<true>(Bitboard *b) {
-
-  unsigned long idx;
-  Bitboard bb = *b;
-  BITSCAN_INTRINSIC(&idx, bb);
-  *b &= (bb - 1);
-  return Square(idx);
-}
-
-
 // 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.