Function BigInt_Multiply2

numpy/core/src/multiarray/dragon4.c:476–500

result = in * 2 */

/* result = in * 2 */
static void
BigInt_Multiply2(BigInt *result, const BigInt *in)
{
    /* shift all the blocks by one */
    npy_uint32 carry = 0;

    npy_uint32 *resultCur = result->blocks;
    const npy_uint32 *pLhsCur = in->blocks;
    const npy_uint32 *pLhsEnd = in->blocks + in->length;
    for ( ; pLhsCur != pLhsEnd; ++pLhsCur, ++resultCur) {
        npy_uint32 cur = *pLhsCur;
        *resultCur = (cur << 1) | carry;
        carry = cur >> 31;
    }

    if (carry != 0) {
        /* grow the array */
        DEBUG_ASSERT(in->length + 1 <= c_BigInt_MaxBlocks);
        *resultCur = carry;
        result->length = in->length + 1;
    }
    else {
        result->length = in->length;
    }
}

/* result = result * 2 */
static void