论文标题
ISO 18037：2008标准定点算术的GCC实施中四舍五入的问题
Issues with rounding in the GCC implementation of the ISO 18037:2008 standard fixed-point arithmetic
论文作者
论文摘要
我们描述了\ textit {gcc}编译器实现定点算术数据类型和操作中缺乏循环模式引起的各种问题。我们证明，在常数的转换，从一种数值类型转换为较不精确的类型和乘法的结果中，圆头到达最佳。此外，我们表明，即使在进行算术操作之前，在固定点算术算术算术中的混合精确操作也是如此。创建了ISO 18037：2008标准是为了标准化嵌入式系统的C语言扩展（包括定点算术）。嵌入式系统通常基于手臂处理器，目前已经制造了约1000亿。因此，考虑到这些嵌入式系统正在运行的广泛的应用程序类型，我们在本文中讨论的数值问题的观察可能非常危险，并且很重要。
We describe various issues caused by the lack of round-to-nearest mode in the \textit{gcc} compiler implementation of the fixed-point arithmetic data types and operations. We demonstrate that round-to-nearest is not performed in the conversion of constants, conversion from one numerical type to a less precise type and results of multiplications. Furthermore, we show that mixed-precision operations in fixed-point arithmetic lose precision on arguments, even before carrying out arithmetic operations. The ISO 18037:2008 standard was created to standardize C language extensions, including fixed-point arithmetic, for embedded systems. Embedded systems are usually based on ARM processors, of which approximately 100 billion have been manufactured by now. Therefore, the observations about numerical issues that we discuss in this paper can be rather dangerous and are important to address, given the wide ranging type of applications that these embedded systems are running.
