// license:BSD-3-Clause // copyright-holders:Tyler J. Stachecki,Ryan Holtz inline rsp_vec_t vec_vmadl_vmudl(uint32_t iw, rsp_vec_t vs, rsp_vec_t vt, rsp_vec_t zero, rsp_vec_t *acc_lo, rsp_vec_t *acc_md, rsp_vec_t *acc_hi) { rsp_vec_t hi = _mm_mulhi_epu16(vs, vt); if (iw & 0x8) // VMADL { // 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, hi); *acc_lo = _mm_add_epi16(*acc_lo, hi); overflow_mask = _mm_cmpeq_epi16(*acc_lo, overflow_mask); overflow_mask = _mm_cmpeq_epi16(overflow_mask, zero); hi = _mm_sub_epi16(zero, overflow_mask); // Check for overflow of the upper sum. // // TODO: Since hi can only be {0,1}, we should // be able to generalize this for performance. overflow_mask = _mm_adds_epu16(*acc_md, hi); *acc_md = _mm_add_epi16(*acc_md, hi); overflow_mask = _mm_cmpeq_epi16(*acc_md, overflow_mask); overflow_mask = _mm_cmpeq_epi16(overflow_mask, zero); // Finish up the accumulation of the... accumulator. // Since the product was unsigned, only worry about // positive overflow (i.e.: borrowing not possible). *acc_hi = _mm_sub_epi16(*acc_hi, overflow_mask); return uclamp_acc(*acc_lo, *acc_md, *acc_hi, zero); } else // VMUDL { *acc_lo = hi; *acc_md = zero; *acc_hi = zero; return hi; } }