Rounding corners

Which problem? The rouding corners? You still need to specify an appropriate G64Pn setting.

Or the slow downs at segment ends while milling your "curve"? You may need to specify a different G64Pn setting for that section of code as you may need more blending at these corners in order to maintain a constant speed and smooth out the kinks you've programed into that code.

i think the problem is from how i generate my g-code, and how i describe the roundings and and circles.

Can someone give me advice for a free software for g-cod generating.Because my program is slef made (from my frined programer) .

Why don't you try the freeware version of Sheetcam? There is a limit on the number of lines of code it will generate, but for small one off jobs, it will probably be enough. Other than that you could try Fusion 360 but I think making a POST for your machine might be harder.