Why is the limit in the random32_unbiased function different between the comments and the actual code?

Question

I'm talking about this specific function:

void random32_unbiased(unsigned char *bytes)
  {
    // l = 2^252 + 27742317777372353535851937790883648493.
    // l fits 15 times in 32 bytes (iow, 15 l is the highest multiple of l that fits in 32 bytes)
    static const unsigned char limit[32] = { 0xe3, 0x6a, 0x67, 0x72, 0x8b, 0xce, 0x13, 0x29, 0x8f, 0x30, 0x82, 0x8c, 0x0b, 0xa4, 0x10, 0x39, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0 };
    while(1)
    {
      generate_random_bytes_thread_safe(32, bytes);
      if (!less32(bytes, limit))
        continue;
      sc_reduce32(bytes);
      if (sc_isnonzero(bytes))
        break;
    }
  }

As you can see, the comment states that the limit should be: l = 2^252 + 27742317777372353535851937790883648493

If we perform that simple addition, we'd end with the number: l = 7237005577332262213973186563042994240857116359379907606001950938285454250989

However, when I convert the limit specified in the cpp codebase to decimal value:

static const unsigned char limit[32] = { 0xe3, 0x6a, 0x67, 0x72, 0x8b, 0xce, 0x13, 0x29, 0x8f, 0x30, 0x82, 0x8c, 0x0b, 0xa4, 0x10, 0x39, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0 };

I end with a totally different integer of 256 bits, that in decimal would be:

limit = 102863016385298801202249955531570426590943090958063650200743214154731025858800

Why is there an inconsistency between the limit in the comments and the actual code?

Answer 1

Why is there an inconsistency between the limit in the comments and the actual code?

There's no inconsistency.

l = 2^252 + 27742317777372353535851937790883648493
limit = l * 15 = f00000000000000000000000000000013910a40b8c82308f2913ce8b72676ae3

Reversed byte order:

e36a67728bce13298f30828c0ba41039010000000000000000000000000000f0

The same as defined in:

limit[32] = { 0xe3, 0x6a, 0x67, 0x72, 0x8b, 0xce, 0x13, 0x29, 0x8f, 0x30, 0x82, 0x8c, 0x0b, 0xa4, 0x10, 0x39, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0 }