为android编译程序集 [英] Compiling Assembly for android

问题描述

我找到了 Vikram Aggarwal 的一篇文章，其中谈到了将汇编代码链接到 Android 的 NDK 中，其中甚至还有一些示例代码，展示了如何将 C++ 代码与汇编连接起来.(见 http://www.eggwall.com/2011/09/android-arm-assembly-calling-assembly.html )

I found an article by Vikram Aggarwal that talks about linking Assembly code into Android's NDK, which even has some example code which shows how to connect the C++ code with Assembly. ( see http://www.eggwall.com/2011/09/android-arm-assembly-calling-assembly.html )

我的问题是我想使用相同的函数，但不是从 JNI 存根类调用它，而是想从我的私有类调用我的程序集函数.

My problem is that I want to use the same function but instead of calling it from JNI stub class, I want to call my Assembly function from my private class.

但是在编译时，我收到错误:

But on compilation, I get the error:

error: 'armFunction' was not declared in this scope

有没有人试过这个或者知道如何解决这个问题?

Has anyone tried this or have any idea how to resolve this ?

生成文件:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := quake3

# I want ARM, not thumb.
LOCAL_ARM_MODE := arm    

LOCAL_SRC_FILES := \
    multiple.s \
    macros.h \
    math/Vector2.cpp\
    math/Vector3.cpp\
    math/plane.cpp\
    engine/frustum.cpp\
    engine/BoundingVolume.cpp\
    engine/camera.cpp\
    camera-proxy.cpp\

LOCAL_CFLAGS := -DANDROID_NDK \
                -DDISABLE_IMPORTGL \

LOCAL_LDLIBS := -lGLESv1_CM -ldl -llog
#LOCAL_LDLIBS := -llog -lGLESv2

APP_STL := gnustl_static
APP_CPPFLAGS := -S -frtti -fexceptions
APP_ABI := armeabi armeabi-v7a

include $(BUILD_SHARED_LIBRARY)

cpp 文件中的函数调用:

Function call in cpp file:

void
Java_surreal_quake3_engine_Camera9_nativeGetDirection(JNIEnv* env, jobject thiz)
{
    //Camera* camera = (Camera*) env->GetIntField(thiz, pointerID);

    // get the _Z as the Vector3 java object
    jfieldID vector_fID = env->GetFieldID(cls, "_Z", "Lsurreal/libs/math/Vector3;");
    jobject vector_obj = env->GetObjectField(thiz, vector_fID);

    // call the setter methods on the _vecEye
        //jclass vectorClass = env->FindClass("surreal/libs/math/Vector3");
    jmethodID vector3_set = env->GetMethodID(vector3Class, "set"/*method-name*/, "(FFF)V" /*method-signature*/);
    env->CallVoidMethod(vector_obj, vector3_set, camera->getZ().x, camera->getZ().y, camera->getZ().z);

    int result = armFunction();
}

推荐答案

看类的代码，好像是调用了函数，但是我看不到它的任何声明，因此无法识别.所以你需要在调用之前声明函数的原型(在 C++ 类中):

Looking at the code of the class, it seems like you call the function, but I can't see any declaration of it, so it is not recognized. So you need to have a declaration of the function's prototype before calling it (in the C++ class):

类似于:

int armFunction(void); // << declaration

void Java_surreal_quake3_engine_Camera9_nativeGetDirection(JNIEnv* env, jobject thiz)
{
    // snip - snap
    int result = armFunction(); // << your function call
}

这篇关于为android编译程序集的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！