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1 // Copyright (c) Facebook, Inc. and its affiliates.
2 // All rights reserved.
3 //
4 // Copyright 2019 Google LLC
5 //
6 // This source code is licensed under the BSD-style license found in the
7 // LICENSE file in the root directory of this source tree.
8 
9 #include <assert.h>
10 
11 #include <immintrin.h>
12 
13 #include <xnnpack/igemm.h>
14 
15 
xnn_q8_igemm_ukernel_4x4c2__sse2(size_t mr,size_t nc,size_t kc,size_t ks,const uint8_t ** restrict a,const void * restrict w,uint8_t * restrict c,size_t cm_stride,size_t cn_stride,size_t a_offset,const uint8_t * zero,const union xnn_q8_gemm_params params[restrict static1])16 void xnn_q8_igemm_ukernel_4x4c2__sse2(
17     size_t mr,
18     size_t nc,
19     size_t kc,
20     size_t ks,
21     const uint8_t** restrict a,
22     const void* restrict w,
23     uint8_t* restrict c,
24     size_t cm_stride,
25     size_t cn_stride,
26     size_t a_offset,
27     const uint8_t* zero,
28     const union xnn_q8_gemm_params params[restrict static 1])
29 {
30   assert(mr != 0);
31   assert(mr <= 4);
32   assert(nc != 0);
33   assert(kc != 0);
34   assert(ks != 0);
35   assert(ks % (4 * sizeof(void*)) == 0);
36 
37   uint8_t* c0 = c;
38   uint8_t* c1 = (uint8_t*) ((uintptr_t) c0 + cm_stride);
39   if XNN_UNPREDICTABLE(mr < 2) {
40     c1 = c0;
41   }
42   uint8_t* c2 = (uint8_t*) ((uintptr_t) c1 + cm_stride);
43   if XNN_UNPREDICTABLE(mr <= 2) {
44     c2 = c1;
45   }
46   uint8_t* c3 = (uint8_t*) ((uintptr_t) c2 + cm_stride);
47   if (mr != 4) {
48     c3 = c2;
49   }
50 
51   const __m128i vb_zero_point = _mm_load_si128((const __m128i*) params->sse2.kernel_zero_point);
52 
53   do {
54     __m128i vacc0x0123 = _mm_loadu_si128((const __m128i*) w);
55     __m128i vacc1x0123 = vacc0x0123;
56     __m128i vacc2x0123 = vacc0x0123;
57     __m128i vacc3x0123 = vacc0x0123;
58     w = (const void*) ((uintptr_t) w + 16);
59 
60     const __m128i vzero = _mm_setzero_si128();
61     size_t p = ks;
62     do {
63       const uint8_t* restrict a0 = a[0];
64       if XNN_UNPREDICTABLE(a0 != zero) {
65         a0 = (const uint8_t*) ((uintptr_t) a0 + a_offset);
66       }
67       const uint8_t* restrict a1 = a[1];
68       if XNN_UNPREDICTABLE(a1 != zero) {
69         a1 = (const uint8_t*) ((uintptr_t) a1 + a_offset);
70       }
71       const uint8_t* restrict a2 = a[2];
72       if XNN_UNPREDICTABLE(a2 != zero) {
73         a2 = (const uint8_t*) ((uintptr_t) a2 + a_offset);
74       }
75       const uint8_t* restrict a3 = a[3];
76       if XNN_UNPREDICTABLE(a3 != zero) {
77         a3 = (const uint8_t*) ((uintptr_t) a3 + a_offset);
78       }
79       a += 4;
80 
81       size_t k = kc;
82       while (k >= 8 * sizeof(uint8_t)) {
83         const __m128i va0 = _mm_loadl_epi64((const __m128i*) a0);
84         const __m128i vxa0 = _mm_unpacklo_epi8(va0, vzero);
85         a0 += 8;
86         const __m128i va1 = _mm_loadl_epi64((const __m128i*) a1);
87         const __m128i vxa1 = _mm_unpacklo_epi8(va1, vzero);
88         a1 += 8;
89         const __m128i va2 = _mm_loadl_epi64((const __m128i*) a2);
90         const __m128i vxa2 = _mm_unpacklo_epi8(va2, vzero);
91         a2 += 8;
92         const __m128i va3 = _mm_loadl_epi64((const __m128i*) a3);
93         const __m128i vxa3 = _mm_unpacklo_epi8(va3, vzero);
94         a3 += 8;
95 
96         const __m128i vb0 = _mm_loadl_epi64((const __m128i*) w);
97         const __m128i vxb0 = _mm_sub_epi16(_mm_unpacklo_epi8(vb0, vzero), vb_zero_point);
98         vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
99         vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
100         vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
101         vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
102 
103         const __m128i vb1 = _mm_loadl_epi64((const __m128i*) ((uintptr_t) w + 8));
104         const __m128i vxb1 = _mm_sub_epi16(_mm_unpacklo_epi8(vb1, vzero), vb_zero_point);
105         vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
106         vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
107         vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
108         vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
109 
110         const __m128i vb2 = _mm_loadl_epi64((const __m128i*) ((uintptr_t) w + 16));
111         const __m128i vxb2 = _mm_sub_epi16(_mm_unpacklo_epi8(vb2, vzero), vb_zero_point);
112         vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
113         vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
114         vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
115         vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
116 
117         const __m128i vb3 = _mm_loadl_epi64((const __m128i*) ((uintptr_t) w + 24));
118         const __m128i vxb3 = _mm_sub_epi16(_mm_unpacklo_epi8(vb3, vzero), vb_zero_point);
119         vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
120         vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
121         vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
122         vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
123 
124         w = (void*) ((uintptr_t) w + 32);
125 
126         k -= 8 * sizeof(uint8_t);
127       }
128       if (k != 0) {
129         const __m128i va0 = _mm_loadl_epi64((const __m128i*) a0);
130         const __m128i vxa0 = _mm_unpacklo_epi8(va0, vzero);
131         const __m128i va1 = _mm_loadl_epi64((const __m128i*) a1);
132         const __m128i vxa1 = _mm_unpacklo_epi8(va1, vzero);
133         const __m128i va2 = _mm_loadl_epi64((const __m128i*) a2);
134         const __m128i vxa2 = _mm_unpacklo_epi8(va2, vzero);
135         const __m128i va3 = _mm_loadl_epi64((const __m128i*) a3);
136         const __m128i vxa3 = _mm_unpacklo_epi8(va3, vzero);
137 
138         const __m128i vb0 = _mm_loadl_epi64((const __m128i*) w);
139         const __m128i vxb0 = _mm_sub_epi16(_mm_unpacklo_epi8(vb0, vzero), vb_zero_point);
140         w = (void*) ((uintptr_t) w + 8);
141 
142         vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
143         vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
144         vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
145         vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(0, 0, 0, 0)), vxb0));
146 
147         if (k > 2 * sizeof(uint8_t)) {
148           const __m128i vb1 = _mm_loadl_epi64((const __m128i*) w);
149           const __m128i vxb1 = _mm_sub_epi16(_mm_unpacklo_epi8(vb1, vzero), vb_zero_point);
150           w = (void*) ((uintptr_t) w + 8);
151 
152           vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
153           vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
154           vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
155           vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(1, 1, 1, 1)), vxb1));
156 
157           if (k > 4 * sizeof(uint8_t)) {
158             const __m128i vb2 = _mm_loadl_epi64((const __m128i*) w);
159             const __m128i vxb2 = _mm_sub_epi16(_mm_unpacklo_epi8(vb2, vzero), vb_zero_point);
160             w = (void*) ((uintptr_t) w + 8);
161 
162             vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
163             vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
164             vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
165             vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(2, 2, 2, 2)), vxb2));
166 
167             if (k > 6 * sizeof(uint8_t)) {
168               const __m128i vb3 = _mm_loadl_epi64((const __m128i*) w);
169               const __m128i vxb3 = _mm_sub_epi16(_mm_unpacklo_epi8(vb3, vzero), vb_zero_point);
170               w = (void*) ((uintptr_t) w + 8);
171 
172               vacc0x0123 = _mm_add_epi32(vacc0x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa0, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
173               vacc1x0123 = _mm_add_epi32(vacc1x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa1, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
174               vacc2x0123 = _mm_add_epi32(vacc2x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa2, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
175               vacc3x0123 = _mm_add_epi32(vacc3x0123, _mm_madd_epi16(_mm_shuffle_epi32(vxa3, _MM_SHUFFLE(3, 3, 3, 3)), vxb3));
176             }
177           }
178         }
179       }
180       p -= 4 * sizeof(void*);
181     } while (p != 0);
182 
183     const __m128i vmultiplier = _mm_load_si128((const __m128i*) params->sse2.multiplier);
184     const __m128i vrounding = _mm_load_si128((const __m128i*) params->sse2.rounding);
185 
186     const __m128i vnmask0x0123 = _mm_cmpgt_epi32(_mm_setzero_si128(), vacc0x0123);
187     const __m128i vnmask1x0123 = _mm_cmpgt_epi32(_mm_setzero_si128(), vacc1x0123);
188     const __m128i vnmask2x0123 = _mm_cmpgt_epi32(_mm_setzero_si128(), vacc2x0123);
189     const __m128i vnmask3x0123 = _mm_cmpgt_epi32(_mm_setzero_si128(), vacc3x0123);
190 
191     const __m128i vabsacc0x0123 = _mm_sub_epi32(_mm_xor_si128(vacc0x0123, vnmask0x0123), vnmask0x0123);
192     const __m128i vabsacc1x0123 = _mm_sub_epi32(_mm_xor_si128(vacc1x0123, vnmask1x0123), vnmask1x0123);
193     const __m128i vabsacc2x0123 = _mm_sub_epi32(_mm_xor_si128(vacc2x0123, vnmask2x0123), vnmask2x0123);
194     const __m128i vabsacc3x0123 = _mm_sub_epi32(_mm_xor_si128(vacc3x0123, vnmask3x0123), vnmask3x0123);
195 
196     const __m128i vabsacc0x1032 = _mm_shuffle_epi32(vabsacc0x0123, _MM_SHUFFLE(2, 3, 0, 1));
197     const __m128i vabsacc1x1032 = _mm_shuffle_epi32(vabsacc1x0123, _MM_SHUFFLE(2, 3, 0, 1));
198     const __m128i vabsacc2x1032 = _mm_shuffle_epi32(vabsacc2x0123, _MM_SHUFFLE(2, 3, 0, 1));
199     const __m128i vabsacc3x1032 = _mm_shuffle_epi32(vabsacc3x0123, _MM_SHUFFLE(2, 3, 0, 1));
200 
201     const __m128i vabsprod0x02 = _mm_mul_epu32(vabsacc0x0123, vmultiplier);
202     const __m128i vabsprod1x02 = _mm_mul_epu32(vabsacc1x0123, vmultiplier);
203     const __m128i vabsprod2x02 = _mm_mul_epu32(vabsacc2x0123, vmultiplier);
204     const __m128i vabsprod3x02 = _mm_mul_epu32(vabsacc3x0123, vmultiplier);
205 
206     const __m128i vnmask0x02 = _mm_shuffle_epi32(vnmask0x0123, _MM_SHUFFLE(2, 2, 0, 0));
207     const __m128i vnmask1x02 = _mm_shuffle_epi32(vnmask1x0123, _MM_SHUFFLE(2, 2, 0, 0));
208     const __m128i vnmask2x02 = _mm_shuffle_epi32(vnmask2x0123, _MM_SHUFFLE(2, 2, 0, 0));
209     const __m128i vnmask3x02 = _mm_shuffle_epi32(vnmask3x0123, _MM_SHUFFLE(2, 2, 0, 0));
210 
211     const __m128i vprod0x02 = _mm_sub_epi64(_mm_xor_si128(vabsprod0x02, vnmask0x02), vnmask0x02);
212     const __m128i vprod1x02 = _mm_sub_epi64(_mm_xor_si128(vabsprod1x02, vnmask1x02), vnmask1x02);
213     const __m128i vprod2x02 = _mm_sub_epi64(_mm_xor_si128(vabsprod2x02, vnmask2x02), vnmask2x02);
214     const __m128i vprod3x02 = _mm_sub_epi64(_mm_xor_si128(vabsprod3x02, vnmask3x02), vnmask3x02);
215 
216     const __m128i vq31prod0x02 = _mm_srli_epi64(_mm_add_epi64(vprod0x02, vrounding), 31);
217     const __m128i vq31prod1x02 = _mm_srli_epi64(_mm_add_epi64(vprod1x02, vrounding), 31);
218     const __m128i vq31prod2x02 = _mm_srli_epi64(_mm_add_epi64(vprod2x02, vrounding), 31);
219     const __m128i vq31prod3x02 = _mm_srli_epi64(_mm_add_epi64(vprod3x02, vrounding), 31);
220 
221     const __m128i vabsprod0x13 = _mm_mul_epu32(vabsacc0x1032, vmultiplier);
222     const __m128i vabsprod1x13 = _mm_mul_epu32(vabsacc1x1032, vmultiplier);
223     const __m128i vabsprod2x13 = _mm_mul_epu32(vabsacc2x1032, vmultiplier);
224     const __m128i vabsprod3x13 = _mm_mul_epu32(vabsacc3x1032, vmultiplier);
225 
226     const __m128i vnmask0x13 = _mm_shuffle_epi32(vnmask0x0123, _MM_SHUFFLE(3, 3, 1, 1));
227     const __m128i vnmask1x13 = _mm_shuffle_epi32(vnmask1x0123, _MM_SHUFFLE(3, 3, 1, 1));
228     const __m128i vnmask2x13 = _mm_shuffle_epi32(vnmask2x0123, _MM_SHUFFLE(3, 3, 1, 1));
229     const __m128i vnmask3x13 = _mm_shuffle_epi32(vnmask3x0123, _MM_SHUFFLE(3, 3, 1, 1));
230 
231     const __m128i vprod0x13 = _mm_sub_epi64(_mm_xor_si128(vabsprod0x13, vnmask0x13), vnmask0x13);
232     const __m128i vprod1x13 = _mm_sub_epi64(_mm_xor_si128(vabsprod1x13, vnmask1x13), vnmask1x13);
233     const __m128i vprod2x13 = _mm_sub_epi64(_mm_xor_si128(vabsprod2x13, vnmask2x13), vnmask2x13);
234     const __m128i vprod3x13 = _mm_sub_epi64(_mm_xor_si128(vabsprod3x13, vnmask3x13), vnmask3x13);
235 
236     const __m128i vq31prod0x13 = _mm_srli_epi64(_mm_add_epi64(vprod0x13, vrounding), 31);
237     const __m128i vq31prod1x13 = _mm_srli_epi64(_mm_add_epi64(vprod1x13, vrounding), 31);
238     const __m128i vq31prod2x13 = _mm_srli_epi64(_mm_add_epi64(vprod2x13, vrounding), 31);
239     const __m128i vq31prod3x13 = _mm_srli_epi64(_mm_add_epi64(vprod3x13, vrounding), 31);
240 
241     const __m128i vq31prod0x0213 = _mm_castps_si128(_mm_shuffle_ps(
242         _mm_castsi128_ps(vq31prod0x02), _mm_castsi128_ps(vq31prod0x13), _MM_SHUFFLE(2, 0, 2, 0)));
243     const __m128i vq31prod1x0213 = _mm_castps_si128(_mm_shuffle_ps(
244         _mm_castsi128_ps(vq31prod1x02), _mm_castsi128_ps(vq31prod1x13), _MM_SHUFFLE(2, 0, 2, 0)));
245     const __m128i vq31prod2x0213 = _mm_castps_si128(_mm_shuffle_ps(
246         _mm_castsi128_ps(vq31prod2x02), _mm_castsi128_ps(vq31prod2x13), _MM_SHUFFLE(2, 0, 2, 0)));
247     const __m128i vq31prod3x0213 = _mm_castps_si128(_mm_shuffle_ps(
248         _mm_castsi128_ps(vq31prod3x02), _mm_castsi128_ps(vq31prod3x13), _MM_SHUFFLE(2, 0, 2, 0)));
249 
250     const __m128i vq31prod0x0123 = _mm_shuffle_epi32(vq31prod0x0213, _MM_SHUFFLE(3, 1, 2, 0));
251     const __m128i vq31prod1x0123 = _mm_shuffle_epi32(vq31prod1x0213, _MM_SHUFFLE(3, 1, 2, 0));
252     const __m128i vq31prod2x0123 = _mm_shuffle_epi32(vq31prod2x0213, _MM_SHUFFLE(3, 1, 2, 0));
253     const __m128i vq31prod3x0123 = _mm_shuffle_epi32(vq31prod3x0213, _MM_SHUFFLE(3, 1, 2, 0));
254 
255     const __m128i vremainder_mask = _mm_load_si128((const __m128i*) params->sse2.remainder_mask);
256 
257     const __m128i vrem0x0123 =
258       _mm_add_epi32(_mm_and_si128(vq31prod0x0123, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), vq31prod0x0123));
259     const __m128i vrem1x0123 =
260       _mm_add_epi32(_mm_and_si128(vq31prod1x0123, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), vq31prod1x0123));
261     const __m128i vrem2x0123 =
262       _mm_add_epi32(_mm_and_si128(vq31prod2x0123, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), vq31prod2x0123));
263     const __m128i vrem3x0123 =
264       _mm_add_epi32(_mm_and_si128(vq31prod3x0123, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), vq31prod3x0123));
265 
266     const __m128i vremainder_threshold = _mm_load_si128((const __m128i*) params->sse2.remainder_threshold);
267     const __m128i vshift = _mm_load_si128((const __m128i*) params->sse2.shift);
268 
269     vacc0x0123 = _mm_sub_epi32(_mm_sra_epi32(vq31prod0x0123, vshift), _mm_cmpgt_epi32(vrem0x0123, vremainder_threshold));
270     vacc1x0123 = _mm_sub_epi32(_mm_sra_epi32(vq31prod1x0123, vshift), _mm_cmpgt_epi32(vrem1x0123, vremainder_threshold));
271     vacc2x0123 = _mm_sub_epi32(_mm_sra_epi32(vq31prod2x0123, vshift), _mm_cmpgt_epi32(vrem2x0123, vremainder_threshold));
272     vacc3x0123 = _mm_sub_epi32(_mm_sra_epi32(vq31prod3x0123, vshift), _mm_cmpgt_epi32(vrem3x0123, vremainder_threshold));
273 
274     const __m128i voutput_zero_point = _mm_load_si128((const __m128i*) params->sse2.output_zero_point);
275     const __m128i vacc01x0123 = _mm_adds_epi16(_mm_packs_epi32(vacc0x0123, vacc1x0123), voutput_zero_point);
276     const __m128i vacc23x0123 = _mm_adds_epi16(_mm_packs_epi32(vacc2x0123, vacc3x0123), voutput_zero_point);
277     __m128i vout = _mm_packus_epi16(vacc01x0123, vacc23x0123);
278     vout = _mm_min_epu8(vout, _mm_load_si128((const __m128i*) params->sse2.output_max));
279     vout = _mm_max_epu8(vout, _mm_load_si128((const __m128i*) params->sse2.output_min));
280 
281     if XNN_LIKELY(nc >= 4) {
282       *((uint32_t*) c3) = (uint32_t) _mm_cvtsi128_si32(_mm_srli_si128(vout, 12));
283       c3 += cn_stride;
284       *((uint32_t*) c2) = (uint32_t) _mm_cvtsi128_si32(_mm_unpackhi_epi32(vout, vout));
285       c2 += cn_stride;
286       *((uint32_t*) c1) = (uint32_t) _mm_cvtsi128_si32(_mm_srli_epi64(vout, 32));
287       c1 += cn_stride;
288       *((uint32_t*) c0) = (uint32_t) _mm_cvtsi128_si32(vout);
289       c0 += cn_stride;
290 
291       a = (const uint8_t**restrict) ((uintptr_t) a - ks);
292 
293       nc -= 4;
294     } else {
295       if (nc & 2) {
296         *((uint16_t*) c3) = (uint16_t) _mm_extract_epi16(vout, 6); c3 += 2;
297         *((uint16_t*) c2) = (uint16_t) _mm_extract_epi16(vout, 4); c2 += 2;
298         *((uint16_t*) c1) = (uint16_t) _mm_extract_epi16(vout, 2); c1 += 2;
299         *((uint16_t*) c0) = (uint16_t) _mm_extract_epi16(vout, 0); c0 += 2;
300         vout = _mm_srli_epi32(vout, 16);
301       }
302       if (nc & 1) {
303         *((uint8_t*) c3) = (uint8_t) _mm_extract_epi16(vout, 6);
304         *((uint8_t*) c2) = (uint8_t) _mm_extract_epi16(vout, 4);
305         *((uint8_t*) c1) = (uint8_t) _mm_extract_epi16(vout, 2);
306         *((uint8_t*) c0) = (uint8_t) _mm_cvtsi128_si32(vout);
307       }
308 
309       nc = 0;
310     }
311   } while (nc != 0);
312 }
313