RISC-V: test for instruction extensions

cmake/cpu.cmake

@@ -47,6 +47,38 @@ if (XMRIG_RISCV)
     set(WITH_SSE4_1 OFF)
     set(WITH_AVX2 OFF)
     set(WITH_VAES OFF)
+
+    # default build uses the RV64GC baseline
+    set(RVARCH "rv64gc")
+
+    # for native builds, enable Zba and Zbb if supported by the CPU
+    if(ARCH STREQUAL "native")
+        enable_language(ASM)
+
+        try_run(RANDOMX_ZBA_RUN_FAIL
+            RANDOMX_ZBA_COMPILE_OK
+            ${CMAKE_CURRENT_BINARY_DIR}/
+            ${CMAKE_CURRENT_SOURCE_DIR}/src/crypto/randomx/tests/riscv64_zba.s
+            COMPILE_DEFINITIONS "-march=rv64gc_zba")
+
+        if (RANDOMX_ZBA_COMPILE_OK AND NOT RANDOMX_ZBA_RUN_FAIL)
+            set(RVARCH "${RVARCH}_zba")
+            message(STATUS "RISC-V zba extension detected")
+        endif()
+
+        try_run(RANDOMX_ZBB_RUN_FAIL
+            RANDOMX_ZBB_COMPILE_OK
+            ${CMAKE_CURRENT_BINARY_DIR}/
+            ${CMAKE_CURRENT_SOURCE_DIR}/src/crypto/randomx/tests/riscv64_zbb.s
+            COMPILE_DEFINITIONS "-march=rv64gc_zbb")
+
+        if (RANDOMX_ZBB_COMPILE_OK AND NOT RANDOMX_ZBB_RUN_FAIL)
+            set(RVARCH "${RVARCH}_zbb")
+            message(STATUS "RISC-V zbb extension detected")
+        endif()
+    endif()
+
+    message(STATUS "Using -march=${RVARCH}")
 endif()
 
 add_definitions(-DRAPIDJSON_WRITE_DEFAULT_FLAGS=6) # rapidjson::kWriteNanAndInfFlag | rapidjson::kWriteNanAndInfNullFlag

cmake/flags.cmake

@@ -31,10 +31,8 @@ if (CMAKE_CXX_COMPILER_ID MATCHES GNU)
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=armv7-a -mfpu=neon -flax-vector-conversions")
         add_definitions(-DHAVE_ROTR)
     elseif (XMRIG_RISCV)
-        # RISC-V baseline: rv64gc (RV64IMAFD + Zicsr + Zifencei)
-        # Use rv64gc for broad compatibility, extensions will be detected at runtime
-        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=rv64gc")
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=rv64gc")
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=${RVARCH}")
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=${RVARCH}")
         
         add_definitions(-DHAVE_ROTR)
     else()
@@ -86,10 +84,8 @@ elseif (CMAKE_CXX_COMPILER_ID MATCHES Clang)
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mfpu=neon -march=${CMAKE_SYSTEM_PROCESSOR}")
         add_definitions(-DHAVE_ROTR)
     elseif (XMRIG_RISCV)
-        # RISC-V baseline: rv64gc (RV64IMAFD + Zicsr + Zifencei)
-        # Use rv64gc for broad compatibility, extensions will be detected at runtime
-        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=rv64gc")
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=rv64gc")
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=${RVARCH}")
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=${RVARCH}")
         
         add_definitions(-DHAVE_ROTR)
     else()

src/crypto/randomx/tests/riscv64_zba.s

@@ -0,0 +1,9 @@
+/* RISC-V - test if the Zba extension is present */
+
+.text
+.global main
+
+main:
+    sh1add x6, x6, x7
+    li x10, 0
+    ret

src/crypto/randomx/tests/riscv64_zbb.s

@@ -0,0 +1,9 @@
+/* RISC-V - test if the Zbb extension is present */
+
+.text
+.global main
+
+main:
+    ror x6, x6, x7
+    li x10, 0
+    ret