diff options
Diffstat (limited to 'src/emu/cpu/rsp/vmac.h')
-rw-r--r-- | src/emu/cpu/rsp/vmac.h | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/src/emu/cpu/rsp/vmac.h b/src/emu/cpu/rsp/vmac.h new file mode 100644 index 00000000000..ecf921a261c --- /dev/null +++ b/src/emu/cpu/rsp/vmac.h @@ -0,0 +1,57 @@ +// license:BSD-3-Clause +// copyright-holders:Tyler J. Stachecki,Ryan Holtz + +inline rsp_vec_t vec_vmacf_vmacu(UINT32 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); + } +} |