the zfh detector hacking

.github/workflows/elf-riscv64-cpu-gcc.yml

@@ -7,105 +7,6 @@ on:
     branches: [master]
     paths-ignore: ['**.md']
 jobs:
-  newlib-rv64gcv-gcc:
-    runs-on: ubuntu-20.04
-    steps:
-    - name: cancel-previous-runs
-      uses: styfle/cancel-workflow-action@0.9.0
-      with:
-        access_token: ${{ secrets.GITHUB_TOKEN }}
-    - uses: actions/checkout@v2
-
-    - name: cache-riscv
-      id: cache-riscv
-      uses: actions/cache@v2.1.6
-      with:
-        path: rv64gcv-install
-        key: rv64gcv-newlib-install-20210504
-
-    - name: install-riscv-build-deps
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      run: |
-        sudo apt-get update
-        sudo apt-get install autoconf automake autotools-dev curl python3 libmpc-dev libmpfr-dev libgmp-dev gawk build-essential bison flex texinfo gperf libtool patchutils bc zlib1g-dev libexpat-dev device-tree-compiler
-
-    - name: checkout-riscv-gnu-toolchain
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      uses: actions/checkout@v2
-      with:
-        repository: riscv/riscv-gnu-toolchain
-        path: riscv-gnu-toolchain
-        ref: 28271f03bb538d926ad2889dc8ad1b0cb1b3b45c
-    - name: checkout-riscv-gnu-toolchain-submodules
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      run: |
-        cd riscv-gnu-toolchain
-        git submodule update --init --recursive --depth 1 riscv-binutils
-        git submodule update --init --recursive --depth 1 riscv-gcc
-        git submodule update --init --recursive --depth 1 riscv-glibc
-        git submodule update --init --recursive --depth 1 riscv-dejagnu
-        git submodule update --init --recursive --depth 1 riscv-newlib
-        git submodule update --init --recursive --depth 1 riscv-gdb
-    - name: riscv-gnu-toolchain
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      run: |
-        cd riscv-gnu-toolchain
-        sed -i '/__OBSOLETE_MATH/d' riscv-newlib/newlib/libm/common/math_errf.c
-        ./configure --prefix=$GITHUB_WORKSPACE/rv64gcv-install --with-arch=rv64gcv_zfh
-        make
-
-    - name: checkout-riscv-pk
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      uses: actions/checkout@v2
-      with:
-        repository: riscv/riscv-pk
-        path: riscv-pk
-        ref: ef7bebaf9bf24d3e90bcaae96387ce418e136b6d
-    - name: riscv-pk
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      run: |
-        cd riscv-pk
-        mkdir build
-        cd build
-        export PATH=$GITHUB_WORKSPACE/rv64gcv-install/bin:$PATH
-        ../configure --prefix=$GITHUB_WORKSPACE/rv64gcv-install --with-arch=rv64gcv --host=riscv64-unknown-elf
-        make -j2
-        make install
-
-    - name: checkout-riscv-isa-sim
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      uses: actions/checkout@v2
-      with:
-        repository: riscv/riscv-isa-sim
-        path: riscv-isa-sim
-        ref: 9d4f45c2ebf105503974fc80a42590ca1584c354
-    - name: riscv-isa-sim
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      run: |
-        cd riscv-isa-sim
-        mkdir build
-        cd build
-        export PATH=$GITHUB_WORKSPACE/rv64gcv-install/bin:$PATH
-        ../configure --prefix=$GITHUB_WORKSPACE/rv64gcv-install --with-isa=rv64gcv
-        make -j2
-        make install
-
-    - name: riscv-strip-install
-      if: steps.cache-riscv.outputs.cache-hit != 'true'
-      run: find $GITHUB_WORKSPACE/rv64gcv-install -type f | xargs -i strip -g {} || true
-
-    - name: configure
-      run: export RISCV_ROOT_PATH=$GITHUB_WORKSPACE/rv64gcv-install && mkdir build && cd build && cmake -DCMAKE_TOOLCHAIN_FILE=../toolchains/riscv64-unknown-elf.toolchain.cmake -DNCNN_THREADS=OFF -DNCNN_OPENMP=OFF -DNCNN_BUILD_TOOLS=OFF -DNCNN_BUILD_EXAMPLES=OFF -DNCNN_BUILD_TESTS=ON ..
-    - name: build
-      run: cmake --build build -j 2
-    - name: test
-      run: |
-        sudo apt-get update
-        sudo apt-get install device-tree-compiler
-        export PATH=$GITHUB_WORKSPACE/rv64gcv-install/bin:$PATH
-        cd build
-        TESTS_EXECUTABLE_LOADER=spike TESTS_EXECUTABLE_LOADER_ARGUMENTS="--isa=rv64gcv_zfh;$GITHUB_WORKSPACE/rv64gcv-install/riscv64-unknown-elf/bin/pk" ctest --output-on-failure -j 2
-
   newlib-rv64gc-gcc:
     runs-on: ubuntu-20.04
     steps:

src/cpu.cpp

@@ -142,6 +142,7 @@ static unsigned int g_hwcaps = get_elf_hwcap_from_proc_self_auxv();
 
 #if __riscv
 // from arch/riscv/include/uapi/asm/hwcap.h
+#define COMPAT_HWCAP_ISA_F (1 << ('F' - 'A'))
 #define COMPAT_HWCAP_ISA_V (1 << ('V' - 'A'))
 #endif
 
@@ -412,22 +413,11 @@ int cpu_support_riscv_v()
 
 int cpu_support_riscv_zfh()
 {
+#if defined __ANDROID__ || defined __linux__
 #if __riscv
-#if __riscv_zfh
-    // https://github.com/riscv/riscv-zfinx/blob/master/Zfinx_spec.adoc#5-discovery
-    __fp16 a = 0;
-    asm volatile(
-        "fneg.h     %0, %0  \n"
-        : "=f"(a)
-        : "0"(a)
-        :);
-    union
-    {
-        __fp16 a;
-        unsigned short u;
-    } tmp;
-    tmp.a = a;
-    return tmp.u != 0 ? 1 : 0;
+    // v + f does not imply zfh, but how to discover zfh properly ?
+    // upstream issue https://github.com/riscv/riscv-isa-manual/issues/414
+    return g_hwcaps & COMPAT_HWCAP_ISA_V && g_hwcaps & COMPAT_HWCAP_ISA_F;
 #else
     return 0;
 #endif