code: static int equal(byte b, byte c) {
          int ub = b;
          int uc = c;
          int x = ub ^ uc; /* 0: yes; 1..255: no */
          int y = x; /* 0: yes; 1..255: no */
          y -= 1; /* 4294967295: yes; 0..254: no */
          y >>>= 31; /* 1: yes; 0: no */
          return y;
      }
docs: CONVERT #include "crypto_uint32.h"