我有一个真正的全加器表。现在我想完成加法器，以便它也可以用于减法（带溢出指示器）。 （OF = XYS'+ X'Y'）
x y cin --- cout s
0 0 0 --- 0 0
0 0 1 --- 0 1
0 1 0 --- 0 1
0 1 1 --- 1 0
1 0 0 --- 1 1
1 0 1 --- 1 0
1 1 0 --- 1 0
1 1 1 --- 1 1
cout = xy + xc + yc s = x'y'c + x'yc'+ xy'c'+ xyc
我原以为减法的真实表就是这样：
sub s x y --- overflow
0 0 0 0 --- 0
0 0 0 1 --- 0
0 0 1 0 --- 0
0 0 1 1 --- 1
0 1 0 0 --- 1
0 1 0 1 --- 0
0 1 1 0 --- 0
0 1 1 1 --- 0
这张桌子对吗？
或者我需要使用这个
0 0 0 0 --- 0
0 0 0 1 --- 0
0 0 1 0 --- 0
0 0 1 1 --- 1 === can any one explain why i got 1 in the overflow here?
0 1 0 0 --- 1
0 1 0 1 --- 0
0 1 1 0 --- 0
0 1 1 1 --- 0
1 0 0 0 --- 0
1 0 0 1 --- 0
1 0 1 0 --- 1 is this the correct true table ?
1 0 1 1 --- 0
1 1 0 0 --- 0
1 1 0 1 --- 1
1 1 1 0 --- 0
1 1 1 1 --- 0
这个真正的表是否正确，函数（=溢出）OF = XYS'+ X'Y's 如何为这个制作AU？ 需要帮助PLZ