错误：使用未声明的标识符“VMAXQ_F16”

Question

#include <jni.h>
#include <arm_fp16.h>
#include <arm_neon.h>

void useSIMD_f16() {
    float16_t zero = 0;
    float16x8_t zero_f16x8 = vld1q_dup_f16(&zero);
    float16_t one = 1;
    float16x8_t one_f16x8 = vld1q_dup_f16(&one);
    float16x8_t max = vmaxq_f16(zero_f16x8, one_f16x8);
}

任务“：app：ExternalNativeBuildDebug”执行失败。生成命令失败。执行进程/home/raed/android/sdk/cmake/3.10.2.4988404/bin/ninja时出错，参数为{-c/home/raed/androidstudioprojects/simd/app/.CXX/cmake/debug/armeabi-v7a native-lib}ninja：进入目录`/home/raed/androidstudioprojects/simd/app/.CXX/cmake/debug/armeabi-v7a'[1/2]生成CXX对象cmakefiles/native-lib.dir/native-lib.cpp.o失败K/NDK/22.1.7171670/toolchains/llvm/prebuilt/linux-x86_64/bin/clang++--target=armv7-none-linux-androideabi23--gcc-toolchain=/home/raed/android/sdk/ndk/22.1.7171670/toolchains/llvm/prebuilt/linux-x86_6/sysroot-dnative_lib_exports-g-dandroide-f-f-g-dandroid-f-g-dandroid-f-g-danddata-sections-ffunction-sections-funwind-tables-fstack-protector-strong-no-canonical-prefixes-d_fortify_source=2-march=armv7-a-mthumb-wformat-werror=format-security-o0-fno-limit-debug-info-fpic-md-mt cmakefiles/native-lib.dir/native-lib.cpp.o-Mf cmakefiles/native-lib.dir/native-lib.cpp.o.d-o cmakefiles/native-lib.dir/native-lib.cpp.o-c/home/raed/androidstudioprojects/simd/app/src/main/cpp/native-lib.cpp/home/raed/androidstudioprojects/simd/app/src/main/cpp/native-lib.cpp:7:30:错误：使用未声明标识符'vld1q_dup_f16'^/home/raed/androidstudioprojects/simd/app/src/main/cpp/native-lib.cpp:9:29:错误：使用未声明的标识符'vld1q_dup_f16'float16x8_t one_f16x8=vld1q_dup_f16(&one)；^/home/raed/androidstudioprojects/simd/app/src/main/cpp/native-lib.cpp:10:23:错误：使用未声明的标识符'vmaxq_f16'float16x8_t max=vmaxq_f16(zero_f16x8,one_f16x8)；生成^3个错误。忍者：构建停止：子命令失败。

Answer 1

半精度浮点并不适用于所有Arm目标。检查是否定义了__arm_feature_fp16_vector_arithmetic宏，以确定函数是否可用。

难道不可能在Android上使用霓虹灯16位浮点数？

它不是一个真正的Android的东西；有些Android设备会支持它，有些则不会。这取决于CPU。