fix / 2-layer MIMO performance optimize

openair1/PHY/NR_TRANSPORT/nr_transport_proto.h

@@ -214,6 +214,7 @@ void nr_ulsch_channel_compensation(int **rxdataF_ext,
 */
 void nr_idft(int32_t *z, uint32_t Msc_PUSCH);
 
+void nr_ulsch_shift_llr(int16_t **llr_layers, uint32_t nb_re, uint32_t rxdataF_ext_offset, int shift);
 
 void nr_ulsch_qpsk_qpsk(c16_t *stream0_in, c16_t *stream1_in, c16_t *stream0_out, c16_t *rho01, uint32_t length);
 

openair1/PHY/NR_TRANSPORT/nr_ulsch_llr_computation.c

@@ -3740,3 +3740,14 @@ void nr_ulsch_qam64_qam64(c16_t *stream0_in,
   simde_mm_empty();
   simde_m_empty();
 }
+
+void nr_ulsch_shift_llr(int16_t **llr_layers, uint32_t nb_re, uint32_t rxdataF_ext_offset, int shift)
+{
+  simde__m128i *llr_layers0 = (simde__m128i *)&llr_layers[0][rxdataF_ext_offset];
+  simde__m128i *llr_layers1 = (simde__m128i *)&llr_layers[1][rxdataF_ext_offset];
+
+  for (int i = 0; i < nb_re >> 2; i++) {
+    llr_layers0[i] = simde_mm_srai_epi16(llr_layers0[i], shift);
+    llr_layers1[i] = simde_mm_srai_epi16(llr_layers1[i], shift);
+  }
+}