什么是不能够在GCC划分数的原因 [英] What is the cause of not being able to divide numbers in GCC

问题描述

我有一个非常奇怪的情况。每次我尝试编译我的胳膊项目（LPC2378，codesourcery臂无 - EABI-GCC-4.5.1）我留下了同样的错误，而联

i'm having a very strange situation. Every time I try to compile my arm project (LPC2378, codesourcery arm-none-eabi-gcc-4.5.1) I am left with the same error whilst linking

/media/data/Projects/arm/uart/main.c:39: undefined reference to `__aeabi_uidiv'
/media/data/Projects/arm/uart/main.c:40: undefined reference to `__aeabi_uidiv'

违规的code是这样的：

The offending code looks like this:

U0DLL = ((((PLLCFG & 0x7FFF) + 1) * F_OSC) / ((((PLLCFG & (0xFF << 16)) >> 16) + 1) * ((CCLKCFG & 0xFF) + 1) * 8 * BAUD * 1)) % 256;
U0DLM = ((((PLLCFG & 0x7FFF) + 1) * F_OSC) / ((((PLLCFG & (0xFF << 16)) >> 16) + 1) * ((CCLKCFG & 0xFF) + 1) * 8 * BAUD * 1)) / 256;

我已搜索周围，这是什么可以用，AFAICT造成的，不使用lgcc＆安培; LC选项LD。我已经解决了，仍然错误仍存在。

I've searched around and what this can be caused by, AFAICT, not using lgcc & lc options for LD. I've resolved that and still the error remains.

整个项目可在我的github回购找到。

如果有人可以帮助将不胜收。干杯。

If anybody could help it would be greatly received. Cheers.

推荐答案

CPU的ARM系列不具备原生的整数除法指令。这样，除法需要由一个库功能来实现。 GCC知道这一点，并创建一个引用（你的情况） __ aeabi_uidiv （为 unsigned int类型司）。

The ARM family of CPUs does not have a native integer division instruction. So, division needs to be implemented by a library function. GCC knows this, and creates a reference to (in your case) __aeabi_uidiv (for unsigned int division).

您将需要包含此功能的适当的运行时支持库链接。

You will need to link with an appropriate runtime support library that contains this function.

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