From 5604b255e6012ed44eb03e2e93949d904fc7279b Mon Sep 17 00:00:00 2001
From: Clement <clement@starfivetech.com>
Date: Fri, 21 Oct 2022 02:29:57 +0000
Subject: [PATCH] Add RISC-V 64-bit support

adds a riscv64 target architecture to the Makefile to support RISC-V 64-bit.
Compiled and tested on VisionFive 2 board.

closes https://github.com/official-stockfish/Stockfish/pull/4205

No functional change.
---
 AUTHORS      |  1 +
 src/Makefile | 19 +++++++++++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 89e7c9ed..d4b37e7a 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -43,6 +43,7 @@ Bryan Cross (crossbr)
 candirufish
 Chess13234
 Chris Cain (ceebo)
+clefrks
 Dale Weiler (graphitemaster)
 Dan Schmidt (dfannius)
 Daniel Axtens (daxtens)
diff --git a/src/Makefile b/src/Makefile
index 727466f9..e481aca5 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -116,7 +116,7 @@ ifeq ($(ARCH), $(filter $(ARCH), \
                  x86-64-vnni512 x86-64-vnni256 x86-64-avx512 x86-64-avxvnni x86-64-bmi2 \
                  x86-64-avx2 x86-64-sse41-popcnt x86-64-modern x86-64-ssse3 x86-64-sse3-popcnt \
                  x86-64 x86-32-sse41-popcnt x86-32-sse2 x86-32 ppc-64 ppc-32 e2k \
-                 armv7 armv7-neon armv8 apple-silicon general-64 general-32))
+                 armv7 armv7-neon armv8 apple-silicon general-64 general-32 riscv64))
    SUPPORTED_ARCH=true
 else
    SUPPORTED_ARCH=false
@@ -338,7 +338,11 @@ ifeq ($(findstring e2k,$(ARCH)),e2k)
 	popcnt = yes
 endif
 
+ifeq ($(ARCH),riscv64)
+	arch = riscv64
 endif
+endif
+
 
 ### ==========================================================================
 ### Section 3. Low-level Configuration
@@ -364,11 +368,14 @@ ifeq ($(COMP),gcc)
 	CXX=g++
 	CXXFLAGS += -pedantic -Wextra -Wshadow
 
-	ifeq ($(arch),$(filter $(arch),armv7 armv8))
+	ifeq ($(arch),$(filter $(arch),armv7 armv8 riscv64))
 		ifeq ($(OS),Android)
 			CXXFLAGS += -m$(bits)
 			LDFLAGS += -m$(bits)
 		endif
+		ifeq ($(ARCH),riscv64)
+			CXXFLAGS += -latomic
+		endif
 	else
 		CXXFLAGS += -m$(bits)
 		LDFLAGS += -m$(bits)
@@ -429,11 +436,14 @@ ifeq ($(COMP),clang)
 	endif
 	endif
 
-	ifeq ($(arch),$(filter $(arch),armv7 armv8))
+	ifeq ($(arch),$(filter $(arch),armv7 armv8 riscv64))
 		ifeq ($(OS),Android)
 			CXXFLAGS += -m$(bits)
 			LDFLAGS += -m$(bits)
 		endif
+		ifeq ($(ARCH),riscv64)
+			CXXFLAGS += -latomic
+		endif
 	else
 		CXXFLAGS += -m$(bits)
 		LDFLAGS += -m$(bits)
@@ -757,6 +767,7 @@ help:
 	@echo "apple-silicon           > Apple silicon ARM64"
 	@echo "general-64              > unspecified 64-bit"
 	@echo "general-32              > unspecified 32-bit"
+	@echo "riscv64                 > RISC-V 64-bit"
 	@echo ""
 	@echo "Supported compilers:"
 	@echo ""
@@ -916,7 +927,7 @@ config-sanity: net
 	@test "$(SUPPORTED_ARCH)" = "true"
 	@test "$(arch)" = "any" || test "$(arch)" = "x86_64" || test "$(arch)" = "i386" || \
 	 test "$(arch)" = "ppc64" || test "$(arch)" = "ppc" || test "$(arch)" = "e2k" || \
-	 test "$(arch)" = "armv7" || test "$(arch)" = "armv8" || test "$(arch)" = "arm64"
+	 test "$(arch)" = "armv7" || test "$(arch)" = "armv8" || test "$(arch)" = "arm64" || test "$(arch)" = "riscv64"
 	@test "$(bits)" = "32" || test "$(bits)" = "64"
 	@test "$(prefetch)" = "yes" || test "$(prefetch)" = "no"
 	@test "$(popcnt)" = "yes" || test "$(popcnt)" = "no"
-- 
2.39.2