获取IEEE单precision位的浮点 [英] Getting the IEEE Single-precision bits for a float

问题描述

我需要写一个IEEE单precision浮点数为32位硬件寄存器在一个特定的地址。要做到这一点，我需要一个float类型的变量转换为一个无符号整数。我可以再presentation这样的整数：

I need to write an IEEE single-precision floating point number to a 32-bit hardware register at a particular address. To do that, I need to convert a variable of type float to an unsigned integer. I can get the integer representation like this:

float a = 2.39;
unsigned int *target;
printf("a = %f\n",a);
target = &a;
printf("target = %08X\n",*target);

返回：

a = 2.390000
target = 4018F5C3

都很好。然而，这会导致编译器警告cast.c：12：警告：从兼容的指针类型赋值

All good. However this causes a compiler warning "cast.c:12: warning: assignment from incompatible pointer type"

有没有其他办法做到这一点不产生警告？这是一个特定的硬件，我并不需要处理不同的字节顺序等，我不通过每个字符出于性能的考虑要循环其他一些问题，往往建议。好像你也许能够使用reinter pret_cast在C ++中，但我使用C

Is there any other way to do this which doesn't generate the warning? This is for specific hardware, I don't need to handle different endianness etc and I don't want to loop through each char for performance reasons as some other questions tend to suggest. It seems like you might be able to use reinterpret_cast in C++ but I am using C.

推荐答案

您可以使用双关语的类型与工会，

You can use type punning with a union,

union {
    float f;
    uint32_t u;
} un;
un.f = your_float;
uint32_t target = un.u;

得到位。或者你可以使用的memcpy 。

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