iOS：使用64bit的vDSP功能 [英] iOS: using vDSP functions in 64bit

问题描述

在iOS中，我有一个函数调用依赖于 vDSP_vgathr ，苹果的一名成员加速框架：

  int pix = image.size。高度* image.size.width; 
 float * array =（float *）malloc（sizeof（float）* pix * 4）; 
 float * colorPlane =（float *）malloc（sizeof（float）* pix）; 
 float * y_r =（float *）malloc（sizeof（float）* pix）
 int * malloc（sizeof（int）* pix）
 
 vDSP_vgathr（colorPlane，（const vDSP_Length *）idx，1，y_r，1，（int）（rate * pix））; 
  

我见过一个SO问题，与我得到的错误有关， EXC_I386_GPFLT 和64位系统和非规范指针。 解决方案（和另外一个）我已经看过包含 tgmath.h ，但在使用（成功编译）时，它什么都不做，我仍然得到 EXC_I386_GPFLT 。

我尝试了许多其他可能的解决方案，包括类型化各种对象和不同的函数调用。我怎样才能使这个函数调用工作与64位体系结构？

解决方案

文档为 vDSP_vgathr 说它被定义为

  void vDSP_vgathr（
 float * __ vDSP_A，
 vDSP_Length * __ vDSP_B，
 vDSP_Stride __vDSP_J，
 float * __ vDSP_C，
 vDSP_Stride __vDSP_K，
 vDSP_Length __vDSP_N 
）; 
  

您将一个int传递给该函数， vDSP_Length


 <$> c $ c> unsigned long * idxSend =（unsigned long *）malloc（sizeof（unsigned long）* N）; （i = 0; i< N; i ++）idxSend [i] =（unsigned long）idx [i]; 
 vDSP_vgathr（...，idxSend，...）; 
  

解决了您的问题。

In iOS, I have a function call that depends on vDSP_vgathr, a member of Apple's Accelerate framework:

int pix = image.size.height * image.size.width;
float * array = (float *)malloc(sizeof(float) * pix * 4);
float * colorPlane = (float *)malloc(sizeof(float) * pix);
float * y_r = (float *)malloc(sizeof(float) * pix)
int * malloc(sizeof(int) * pix)

vDSP_vgathr(colorPlane, (const vDSP_Length *)idx, 1, y_r, 1, (int)(rate*pix));

I've seen an SO question that relating to the error I get, EXC_I386_GPFLT, and 64 bit systems and non-canonical pointers. The solution (and another one) I've seen suggest including tgmath.h, but when used (with a successful compile), it does nothing and I still get EXC_I386_GPFLT.

I've tried a host of other potential solutions including typecasting various objects and different function calls. How can I do I make this function call work with the 64 bit architecture?

解决方案

The docs for vDSP_vgathr say it's defined as

void vDSP_vgathr (
   float *__vDSP_A,
   vDSP_Length *__vDSP_B,
   vDSP_Stride __vDSP_J,
   float *__vDSP_C,
   vDSP_Stride __vDSP_K,
   vDSP_Length __vDSP_N
);

You're passing an int into that function and vDSP_Length is defined as unsigned long. So, pass an unsigned long in:

unsigned long * idxSend = (unsigned long *)malloc(sizeof(unsigned long) * N);
for (i=0; i<N; i++) idxSend[i] = (unsigned long)idx[i];
vDSP_vgathr(..., idxSend, ...);

That solves your problem.

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