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// license:BSD-3-Clause
// copyright-holders:Tyler J. Stachecki,Ryan Holtz
inline rsp_vec_t vec_vmacf_vmacu(uint32_t iw, rsp_vec_t vs, rsp_vec_t vt, rsp_vec_t zero, rsp_vec_t *acc_lo, rsp_vec_t *acc_mid, rsp_vec_t *acc_hi)
{
// Get the product and shift it over
// being sure to save the carries.
rsp_vec_t lo = _mm_mullo_epi16(vs, vt);
rsp_vec_t hi = _mm_mulhi_epi16(vs, vt);
rsp_vec_t mid = _mm_slli_epi16(hi, 1);
rsp_vec_t carry = _mm_srli_epi16(lo, 15);
hi = _mm_srai_epi16(hi, 15);
mid = _mm_or_si128(mid, carry);
lo = _mm_slli_epi16(lo, 1);
// Tricky part: start accumulating everything.
// Get/keep the carry as we'll add it in later.
rsp_vec_t overflow_mask = _mm_adds_epu16(*acc_lo, lo);
*acc_lo = _mm_add_epi16(*acc_lo, lo);
overflow_mask = _mm_cmpeq_epi16(*acc_lo, overflow_mask);
overflow_mask = _mm_cmpeq_epi16(overflow_mask, zero);
// Add in the carry. If the middle portion is
// already 0xFFFF and we have a carry, we have
// to carry the all the way up to hi.
mid = _mm_sub_epi16(mid, overflow_mask);
carry = _mm_cmpeq_epi16(mid, zero);
carry = _mm_and_si128(carry, overflow_mask);
hi = _mm_sub_epi16(hi, carry);
// Accumulate the middle portion.
overflow_mask = _mm_adds_epu16(*acc_mid, mid);
*acc_mid = _mm_add_epi16(*acc_mid, mid);
overflow_mask = _mm_cmpeq_epi16(*acc_mid, overflow_mask);
overflow_mask = _mm_cmpeq_epi16(overflow_mask, zero);
// Finish up the accumulation of the... accumulator.
*acc_hi = _mm_add_epi16(*acc_hi, hi);
*acc_hi = _mm_sub_epi16(*acc_hi, overflow_mask);
if (iw & 0x1) // VMACU
{
rsp_vec_t overflow_hi_mask = _mm_srai_epi16(*acc_hi, 15);
rsp_vec_t overflow_mid_mask = _mm_srai_epi16(*acc_mid, 15);
mid = _mm_or_si128(overflow_mid_mask, *acc_mid);
overflow_mask = _mm_cmpgt_epi16(*acc_hi, zero);
mid = _mm_andnot_si128(overflow_hi_mask, mid);
return _mm_or_si128(overflow_mask, mid);
}
else // VMACF
{
return sclamp_acc_to_mid(*acc_mid, *acc_hi);
}
}
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