怎么将ASCII数转换为整数

嗨论坛，
这似乎应该是一个简单的，但我找不到我需要的答案。
我从GPS接收器接收ASCII格式的UTC时间，我需要将它们转换为整数，以便我可以对它们进行操作（例如，当我们丢失GPS时保持时钟）。
我在硬件中这样做是因为我需要次秒定时精度。
现在问题是你如何有效地转换ASCII数字，例如2017年（ASCII中的四个字节）到unsigned int？
我想出的唯一方法是做数学，2 * 1000 + 0 * 100 + 1 * 10 + 7，在FPGA上不理想。
还有更多的切割方法吗？
我想我可以在查找表中对这些年进行硬编码，然后我只需要对数字进行数学计算，最多可以达到60（分钟/秒）。
谢谢



以下为原文

Hi forum,

This seems like it should have been a simple one but I am not find the answers I need.  I receive UTC time in ASCII format from the GPS receiver, and I need to convert them to integers so I can operate on them (for example maintaining clock when we loss GPS).  I am doing this in hardware because I need the sub second timing accuracy.  Now the question is how do you efficiently convert a ASCII number, say for example the year 2017 (four bytes in ASCII) to unsigned int?  The only way I came up with is to do math, 2*1000+0*100+1*10+7, not ideal on a fpga.  Are there any more cleaver methods out there?  I suppose I could hard code the years in a lookup table, and then I would only have to do math on numbers up to 60 (for the minutes/seconds).

Thanks