Update

* Renamed __popcount_use_table to __popcount_table.
* [PPC] Added PowerPC support from ppc32 to Power10.

src/Makefile

@@ -198,7 +198,7 @@ ifeq ($(COMP),gcc)
                    -Wshadow
 else ifeq ($(COMP),clang)
     SF_CXXFLAGS += -pedantic -Wextra -Wcast-qual -Wconditional-uninitialized \
-                -Wmissing-prototypes -Wshadow
+                   -Wmissing-prototypes -Wshadow
 else ifeq ($(COMP),icx)
     SF_CXXFLAGS += -Wabi -Wmissing-declarations -Wmissing-prototypes -Wshadow
 endif
@@ -274,13 +274,17 @@ ifeq ($(ARCH),)
 endif
 
 ifeq ($(ARCH),native)
+    # -march=native is not available on some architectures.
+    # Need some automatic detection here.
     ARCH_NATIVE := y
     SF_CXXFLAGS += -march=native -DARCH_NATIVE
 else
     ifneq ($(filter x86%,$(ARCH)),)
         ARCH_FAMILY := i386
     else ifneq ($(filter arm%,$(ARCH)),)
         ARCH_FAMILY := arm
+    else ifneq ($(filter ppc%,$(ARCH)),)
+        ARCH_FAMILY := ppc
     else
         ARCH_FAMILY := generic
     endif

src/arch/i386/arch.h

@@ -136,7 +136,7 @@ inline unsigned int ArchImpl::popcount(T n) {
         return _mm_popcnt_u32(std::uint32_t(n));
 #else
     if constexpr (!is_64bit() && sizeof(T) == 8)
-        return __popcount_use_table(n);
+        return __popcount_table(n);
     else
         return __popcount_value(n);
 #endif

src/arch/ppc/Makefile

@@ -0,0 +1,48 @@
+define HELP_STRING_PPC
+To build Stockfish, run the following command:
+
+make <build-target> [ARCH=<preset>]
+
+Build presets for PowerPC architecture:
+
+ppc-power10             > Power10
+ppc-power9              > Power9
+ppc-power8              > Power8
+ppc-power7              > Power7
+ppc-64                  > PowerPC 64-bit
+ppc-32                  > PowerPC 32-bit
+
+endef
+export HELP_STRING_PPC
+
+ifneq ($(filter $(COMP),gcc clang icx),)
+
+ifeq ($(ARCH),ppc-power10)
+    SF_CXXFLAGS += -mcpu=power10
+else ifeq ($(ARCH),ppc-power9)
+    SF_CXXFLAGS += -mcpu=power9
+else ifeq ($(ARCH),ppc-power8)
+    SF_CXXFLAGS += -mcpu=power8
+else ifeq ($(ARCH),ppc-power7)
+    SF_CXXFLAGS += -mcpu=power7
+else ifeq ($(ARCH),ppc-64)
+    SF_CXXFLAGS += -mcpu=powerpc64
+else ifeq ($(ARCH),ppc-32)
+    SF_CXXFLAGS += -mcpu=powerpc
+endif
+
+endif   # gcc clang icx
+
+.PHONY: help-arch config-sanity-arch
+
+help-arch:
+	@echo "$${HELP_STRING_PPC}"
+
+config-sanity-arch:
+	@[ "$(ARCH)" = "ppc-power10" -o \
+	   "$(ARCH)" = "ppc-power9" -o \
+	   "$(ARCH)" = "ppc-power8" -o \
+	   "$(ARCH)" = "ppc-power7" -o \
+	   "$(ARCH)" = "ppc-64" -o \
+	   "$(ARCH)" = "ppc-32" \
+	]

src/arch/ppc/arch.h

@@ -0,0 +1,66 @@
+/*
+  Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+  Copyright (C) 2004-2024 The Stockfish developers (see AUTHORS file)
+
+  Stockfish is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  Stockfish is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef PPC_ARCH_H_INCLUDED
+#define PPC_ARCH_H_INCLUDED
+
+#if !defined(__PPC__)
+#error "Not supported in the current architecture."
+#endif
+
+#include <cassert>
+#include <cstdint>
+#include <type_traits>
+
+#include "common.h"
+
+#if STOCKFISH_COMPILER == STOCKFISH_COMPILER_GCC
+#include <ppu_intrinsics.h>
+#endif
+
+namespace Stockfish {
+
+#ifdef __PPC64__
+inline constexpr bool ArchImpl::Is64Bit = true;
+#else
+inline constexpr bool ArchImpl::Is64Bit = false;
+#endif
+
+inline constexpr bool ArchImpl::UsePEXT = false;
+
+template<int Hint>
+inline void ArchImpl::prefetch(const void* m) {
+    __dcbt(m);
+}
+
+template<typename T>
+inline unsigned int ArchImpl::popcount(T n) {
+    static_assert(std::is_integral_v<T> && sizeof(T) <= 8);
+
+    // This will generate POPCNTD instruction on PWR7 and later.
+    return __popcount_value(n);
+}
+
+template<typename T>
+inline T ArchImpl::pext([[maybe_unused]] T n, [[maybe_unused]] T mask) {
+    return 0;
+}
+
+}  // namespace Stockfish
+
+#endif  // I386_ARCH_H_INCLUDED

src/common.h

@@ -100,10 +100,9 @@ enum class PrefetchHint;
 
 // This struct is used to provide generalized functionalities that might have
 // different implementations depending on the target architecture. Each
-// function defined in this struct is specialized in arch.h file respectively.
+// member and function defined in this struct is specialized in arch.h file
+// respectively.
 struct ArchImpl {
-    /// Does the struct name fit to its purpose?
-
     static const bool Is64Bit;
 
     static const bool UsePEXT;  // used in Bitboard
@@ -130,7 +129,7 @@ constexpr bool use_pext() { return ArchImpl::UsePEXT; }
 // 32-bit environment. Therefore we provide two versions of it and leave it
 // for each platform to decide which one to use.
 template<typename T>
-inline int __popcount_use_table(T n) {
+inline int __popcount_table(T n) {
     static_assert(std::is_integral_v<T> && sizeof(T) % 2 == 0);
 
     static const std::array<std::uint8_t, 1 << 16> popcntTable = [] {
@@ -196,6 +195,10 @@ inline T pext(T n, T mask) {
 
     #include "arch/arm/arch.h"
 
+#elif defined(__PPC__)
+
+    #include "arch/ppc/arch.h"
+
 #else
 
     #include "arch/generic/arch.h"