intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 105 insertions, 0 deletions

diff --git a/library/cpp/pop_count/popcount.h b/library/cpp/pop_count/popcount.h
new file mode 100644
index 00000000000..3d67737ed25
--- /dev/null
+++ b/library/cpp/pop_count/popcount.h
@@ -0,0 +1,105 @@
+#pragma once
+
+#include <util/generic/typelist.h>
+#include <util/system/cpu_id.h>
+#include <util/system/defaults.h>
+#include <util/system/hi_lo.h>
+#include <util/system/platform.h>
+
+#if defined(_MSC_VER)
+#include <intrin.h>
+#endif
+
+static inline ui32 PopCountImpl(ui8 n) {
+#if defined(_ppc64_)
+    ui32 r;
+    __asm__("popcntb %0, %1"
+            : "=r"(r)
+            : "r"(n)
+            :);
+    return r;
+#else
+    extern ui8 const* PopCountLUT8;
+    return PopCountLUT8[n];
+#endif
+}
+
+static inline ui32 PopCountImpl(ui16 n) {
+#if defined(_MSC_VER)
+    return __popcnt16(n);
+#else
+    extern ui8 const* PopCountLUT16;
+    return PopCountLUT16[n];
+#endif
+}
+
+static inline ui32 PopCountImpl(ui32 n) {
+#if defined(_MSC_VER)
+    return __popcnt(n);
+#else
+#if defined(_x86_64_)
+    if (NX86::CachedHavePOPCNT()) {
+        ui32 r;
+
+        __asm__("popcnt %1, %0;"
+                : "=r"(r)
+                : "r"(n)
+                :);
+
+        return r;
+    }
+#else
+#if defined(_ppc64_)
+    ui32 r;
+
+    __asm__("popcntw %0, %1"
+            : "=r"(r)
+            : "r"(n)
+            :);
+
+    return r;
+#endif
+#endif
+
+    return PopCountImpl((ui16)Lo16(n)) + PopCountImpl((ui16)Hi16(n));
+#endif
+}
+
+static inline ui32 PopCountImpl(ui64 n) {
+#if defined(_MSC_VER) && !defined(_i386_)
+    return __popcnt64(n);
+#else
+#if defined(_x86_64_)
+    if (NX86::CachedHavePOPCNT()) {
+        ui64 r;
+
+        __asm__("popcnt %1, %0;"
+                : "=r"(r)
+                : "r"(n)
+                :);
+
+        return r;
+    }
+#else
+#if defined(_ppc64_)
+    ui32 r;
+
+    __asm__("popcntd %0, %1"
+            : "=r"(r)
+            : "r"(n)
+            :);
+
+    return r;
+#endif
+#endif
+
+    return PopCountImpl((ui32)Lo32(n)) + PopCountImpl((ui32)Hi32(n));
+#endif
+}
+
+template <class T>
+static inline ui32 PopCount(T n) {
+    using TCvt = TFixedWidthUnsignedInt<T>;
+
+    return PopCountImpl((TCvt)n);
+}