Assembly equivalent

What is following code in assembly is equivalent of higher language like C?

Code:

---

cwd
xor ax,dx
sub ax,dx

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If you have anything similar assembly snapshot equvalent to C, let me know...

My reference for cwd says that the CWD converts a word to a double word.

I think something similar to this code would be

typedef unsigned short uint16;
typedef unsigned int uint32;

cwd
xor ax,dx
sub ax,dx


uint16 a = 5;
uint32 b;
uint32 c = 6;

b = (uint32)a; // cwd
b ^= c; // xor
b -= c; // sub