41   u32 x[16];  in chacha_block()  local
42   memcpy(x, in, 64);  in chacha_block()
44     QR(x[0], x[4], x[ 8], x[12]);  in chacha_block()
45     QR(x[1], x[5], x[ 9], x[13]);  in chacha_block()
46     QR(x[2], x[6], x[10], x[14]);  in chacha_block()
47     QR(x[3], x[7], x[11], x[15]);  in chacha_block()
48     QR(x[0], x[5], x[10], x[15]);  in chacha_block()
49     QR(x[1], x[6], x[11], x[12]);  in chacha_block()
50     QR(x[2], x[7], x[ 8], x[13]);  in chacha_block()
51     QR(x[3], x[4], x[ 9], x[14]);  in chacha_block()
53   for(i=0; i<16; i++) out[i] = x[i]+in[i];  in chacha_block()