src/qu8-requantization/gemmlowp-ssse3.c - platform/external/XNNPACK - Git at Google

 // Copyright (c) Facebook, Inc. and its affiliates.
 // All rights reserved.
 //
 // Copyright 2019 Google LLC
 //
 // This source code is licensed under the BSD-style license found in the
 // LICENSE file in the root directory of this source tree.

 #include <assert.h>
 #include <stdint.h>
 #include <stddef.h>

 #include <tmmintrin.h>

 #include <xnnpack/math.h>
 #include <xnnpack/requantization-stubs.h>


 void xnn_qu8_requantize_gemmlowp__ssse3(
     size_t n,
     const int32_t* input,
     float scale,
     uint8_t zero_point,
     uint8_t qmin,
     uint8_t qmax,
     uint8_t* output)
 {
   assert(n % 16 == 0);
   assert(scale < 1.0f);
   assert(scale >= 0x1.0p-32f);

   // Compute requantization parameters.
   const uint32_t scale_bits = float_as_uint32(scale);

   // Multiplier is in [0x40000000, 0x7FFFFF80] range.
   const int32_t multiplier = (int32_t)(((scale_bits & UINT32_C(0x007FFFFF)) | UINT32_C(0x00800000)) << 7);
   assert(multiplier >= INT32_C(0x40000000));
   assert(multiplier <= INT32_C(0x7FFFFF80));

   // Shift is in [0, 31] range.
   const int32_t shift = 127 + 31 - 32 - (float_as_uint32(scale) >> 23);
   assert(shift >= 0);
   assert(shift < 32);

   const __m128i vmultiplier = _mm_set1_epi32(multiplier);
   const __m128i vzero_point = _mm_set1_epi16((short) (uint16_t) zero_point);
   const __m128i vqmin = _mm_set1_epi8((char) qmin);
   const __m128i vqmax = _mm_set1_epi8((char) qmax);
   const __m128i vshift = _mm_cvtsi32_si128((int) shift);
   const uint32_t remainder_mask = (UINT32_C(1) << shift) - UINT32_C(1);
   const __m128i vremainder_mask = _mm_set1_epi32((int) remainder_mask);
   const __m128i vthreshold = _mm_set1_epi32((int) (remainder_mask >> 1));
   const __m128i vq31rounding = _mm_set1_epi64x(UINT64_C(0x40000000));
   for (; n != 0; n -= 16) {
     const __m128i x = _mm_loadu_si128((const __m128i*) input);
     const __m128i y = _mm_loadu_si128((const __m128i*) (input + 4));
     const __m128i z = _mm_loadu_si128((const __m128i*) (input + 8));
     const __m128i w = _mm_loadu_si128((const __m128i*) (input + 12));
     input += 16;

     const __m128i x_abs = _mm_abs_epi32(x);
     const __m128i y_abs = _mm_abs_epi32(y);
     const __m128i z_abs = _mm_abs_epi32(z);
     const __m128i w_abs = _mm_abs_epi32(w);

     const __m128i x_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), x);
     const __m128i y_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), y);
     const __m128i z_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), z);
     const __m128i w_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), w);

     const __m128i x_abs_rev = _mm_shuffle_epi32(x_abs, _MM_SHUFFLE(2, 3, 0, 1));
     const __m128i y_abs_rev = _mm_shuffle_epi32(y_abs, _MM_SHUFFLE(2, 3, 0, 1));
     const __m128i z_abs_rev = _mm_shuffle_epi32(z_abs, _MM_SHUFFLE(2, 3, 0, 1));
     const __m128i w_abs_rev = _mm_shuffle_epi32(w_abs, _MM_SHUFFLE(2, 3, 0, 1));

     const __m128i x_abs_product_even = _mm_mul_epu32(x_abs, vmultiplier);
     const __m128i y_abs_product_even = _mm_mul_epu32(y_abs, vmultiplier);
     const __m128i z_abs_product_even = _mm_mul_epu32(z_abs, vmultiplier);
     const __m128i w_abs_product_even = _mm_mul_epu32(w_abs, vmultiplier);

     const __m128i x_neg_mask_even = _mm_shuffle_epi32(x_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));
     const __m128i y_neg_mask_even = _mm_shuffle_epi32(y_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));
     const __m128i z_neg_mask_even = _mm_shuffle_epi32(z_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));
     const __m128i w_neg_mask_even = _mm_shuffle_epi32(w_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));

     const __m128i x_product_even = _mm_sub_epi64(_mm_xor_si128(x_abs_product_even, x_neg_mask_even), x_neg_mask_even);
     const __m128i y_product_even = _mm_sub_epi64(_mm_xor_si128(y_abs_product_even, y_neg_mask_even), y_neg_mask_even);
     const __m128i z_product_even = _mm_sub_epi64(_mm_xor_si128(z_abs_product_even, z_neg_mask_even), z_neg_mask_even);
     const __m128i w_product_even = _mm_sub_epi64(_mm_xor_si128(w_abs_product_even, w_neg_mask_even), w_neg_mask_even);

     const __m128i x_rounded_product_even = _mm_add_epi64(x_product_even, vq31rounding);
     const __m128i y_rounded_product_even = _mm_add_epi64(y_product_even, vq31rounding);
     const __m128i z_rounded_product_even = _mm_add_epi64(z_product_even, vq31rounding);
     const __m128i w_rounded_product_even = _mm_add_epi64(w_product_even, vq31rounding);

     const __m128i x_abs_product_odd = _mm_mul_epu32(x_abs_rev, vmultiplier);
     const __m128i y_abs_product_odd = _mm_mul_epu32(y_abs_rev, vmultiplier);
     const __m128i z_abs_product_odd = _mm_mul_epu32(z_abs_rev, vmultiplier);
     const __m128i w_abs_product_odd = _mm_mul_epu32(w_abs_rev, vmultiplier);

     const __m128i x_neg_mask_odd = _mm_shuffle_epi32(x_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));
     const __m128i y_neg_mask_odd = _mm_shuffle_epi32(y_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));
     const __m128i z_neg_mask_odd = _mm_shuffle_epi32(z_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));
     const __m128i w_neg_mask_odd = _mm_shuffle_epi32(w_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));

     const __m128i x_product_odd = _mm_sub_epi64(_mm_xor_si128(x_abs_product_odd, x_neg_mask_odd), x_neg_mask_odd);
     const __m128i y_product_odd = _mm_sub_epi64(_mm_xor_si128(y_abs_product_odd, y_neg_mask_odd), y_neg_mask_odd);
     const __m128i z_product_odd = _mm_sub_epi64(_mm_xor_si128(z_abs_product_odd, z_neg_mask_odd), z_neg_mask_odd);
     const __m128i w_product_odd = _mm_sub_epi64(_mm_xor_si128(w_abs_product_odd, w_neg_mask_odd), w_neg_mask_odd);

     const __m128i x_rounded_product_odd = _mm_add_epi64(x_product_odd, vq31rounding);
     const __m128i y_rounded_product_odd = _mm_add_epi64(y_product_odd, vq31rounding);
     const __m128i z_rounded_product_odd = _mm_add_epi64(z_product_odd, vq31rounding);
     const __m128i w_rounded_product_odd = _mm_add_epi64(w_product_odd, vq31rounding);

     const __m128i x_q31product_even = _mm_srli_epi64(x_rounded_product_even, 31);
     const __m128i x_q31product_odd = _mm_srli_epi64(x_rounded_product_odd, 31);
     const __m128i y_q31product_even = _mm_srli_epi64(y_rounded_product_even, 31);
     const __m128i y_q31product_odd = _mm_srli_epi64(y_rounded_product_odd, 31);
     const __m128i z_q31product_even = _mm_srli_epi64(z_rounded_product_even, 31);
     const __m128i z_q31product_odd = _mm_srli_epi64(z_rounded_product_odd, 31);
     const __m128i w_q31product_even = _mm_srli_epi64(w_rounded_product_even, 31);
     const __m128i w_q31product_odd = _mm_srli_epi64(w_rounded_product_odd, 31);

     const __m128i x_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
         _mm_castsi128_ps(x_q31product_even), _mm_castsi128_ps(x_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));
     const __m128i y_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
         _mm_castsi128_ps(y_q31product_even), _mm_castsi128_ps(y_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));
     const __m128i z_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
         _mm_castsi128_ps(z_q31product_even), _mm_castsi128_ps(z_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));
     const __m128i w_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
         _mm_castsi128_ps(w_q31product_even), _mm_castsi128_ps(w_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));

     const __m128i x_q31product = _mm_shuffle_epi32(x_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));
     const __m128i y_q31product = _mm_shuffle_epi32(y_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));
     const __m128i z_q31product = _mm_shuffle_epi32(z_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));
     const __m128i w_q31product = _mm_shuffle_epi32(w_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));

     const __m128i x_remainder =
         _mm_add_epi32(_mm_and_si128(x_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), x_q31product));
     const __m128i y_remainder =
         _mm_add_epi32(_mm_and_si128(y_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), y_q31product));
     const __m128i z_remainder =
         _mm_add_epi32(_mm_and_si128(z_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), z_q31product));
     const __m128i w_remainder =
         _mm_add_epi32(_mm_and_si128(w_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), w_q31product));

     const __m128i x_scaled =
         _mm_sub_epi32(_mm_sra_epi32(x_q31product, vshift), _mm_cmpgt_epi32(x_remainder, vthreshold));
     const __m128i y_scaled =
         _mm_sub_epi32(_mm_sra_epi32(y_q31product, vshift), _mm_cmpgt_epi32(y_remainder, vthreshold));
     const __m128i z_scaled =
         _mm_sub_epi32(_mm_sra_epi32(z_q31product, vshift), _mm_cmpgt_epi32(z_remainder, vthreshold));
     const __m128i w_scaled =
         _mm_sub_epi32(_mm_sra_epi32(w_q31product, vshift), _mm_cmpgt_epi32(w_remainder, vthreshold));

     const __m128i xy_packed = _mm_adds_epi16(_mm_packs_epi32(x_scaled, y_scaled), vzero_point);
     const __m128i zw_packed = _mm_adds_epi16(_mm_packs_epi32(z_scaled, w_scaled), vzero_point);
     const __m128i xyzw_packed = _mm_packus_epi16(xy_packed, zw_packed);
     const __m128i xyzw_clamped = _mm_max_epu8(_mm_min_epu8(xyzw_packed, vqmax), vqmin);

     // 16x PSHUFD
     // 4x SHUFPS
     // 8x PMULUDQ
     // 8x PXOR (setzero)
     // 8x PXOR
     // 4x PAND
     // 8x PADDQ
     // 4x PADDD
     // 2x PADDW
     // 8x PSUBQ
     // 4x PSUBD
     // 8x PSRLQ (immediate)
     // 4x PSRAD (register)
     // 12x PCMPGTD
     // 4x PABSD
     // 2x PACKSSDW
     // 1x PACKUSWB
     // 1x PMAXUB
     // 1x PMINUB
     // ---------------------
     // 107 instructions total

     _mm_storeu_si128((__m128i*) output, xyzw_clamped);
     output += 16;
   }
 }
	// Copyright (c) Facebook, Inc. and its affiliates.
	// All rights reserved.
	//
	// Copyright 2019 Google LLC
	//
	// This source code is licensed under the BSD-style license found in the
	// LICENSE file in the root directory of this source tree.

	#include <assert.h>
	#include <stdint.h>
	#include <stddef.h>

	#include <tmmintrin.h>

	#include <xnnpack/math.h>
	#include <xnnpack/requantization-stubs.h>


	void xnn_qu8_requantize_gemmlowp__ssse3(
	size_t n,
	const int32_t* input,
	float scale,
	uint8_t zero_point,
	uint8_t qmin,
	uint8_t qmax,
	uint8_t* output)
	{
	assert(n % 16 == 0);
	assert(scale < 1.0f);
	assert(scale >= 0x1.0p-32f);

	// Compute requantization parameters.
	const uint32_t scale_bits = float_as_uint32(scale);

	// Multiplier is in [0x40000000, 0x7FFFFF80] range.
	const int32_t multiplier = (int32_t)(((scale_bits & UINT32_C(0x007FFFFF)) \| UINT32_C(0x00800000)) << 7);
	assert(multiplier >= INT32_C(0x40000000));
	assert(multiplier <= INT32_C(0x7FFFFF80));

	// Shift is in [0, 31] range.
	const int32_t shift = 127 + 31 - 32 - (float_as_uint32(scale) >> 23);
	assert(shift >= 0);
	assert(shift < 32);

	const __m128i vmultiplier = _mm_set1_epi32(multiplier);
	const __m128i vzero_point = _mm_set1_epi16((short) (uint16_t) zero_point);
	const __m128i vqmin = _mm_set1_epi8((char) qmin);
	const __m128i vqmax = _mm_set1_epi8((char) qmax);
	const __m128i vshift = _mm_cvtsi32_si128((int) shift);
	const uint32_t remainder_mask = (UINT32_C(1) << shift) - UINT32_C(1);
	const __m128i vremainder_mask = _mm_set1_epi32((int) remainder_mask);
	const __m128i vthreshold = _mm_set1_epi32((int) (remainder_mask >> 1));
	const __m128i vq31rounding = _mm_set1_epi64x(UINT64_C(0x40000000));
	for (; n != 0; n -= 16) {
	const __m128i x = _mm_loadu_si128((const __m128i*) input);
	const __m128i y = _mm_loadu_si128((const __m128i*) (input + 4));
	const __m128i z = _mm_loadu_si128((const __m128i*) (input + 8));
	const __m128i w = _mm_loadu_si128((const __m128i*) (input + 12));
	input += 16;

	const __m128i x_abs = _mm_abs_epi32(x);
	const __m128i y_abs = _mm_abs_epi32(y);
	const __m128i z_abs = _mm_abs_epi32(z);
	const __m128i w_abs = _mm_abs_epi32(w);

	const __m128i x_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), x);
	const __m128i y_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), y);
	const __m128i z_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), z);
	const __m128i w_neg_mask = _mm_cmpgt_epi32(_mm_setzero_si128(), w);

	const __m128i x_abs_rev = _mm_shuffle_epi32(x_abs, _MM_SHUFFLE(2, 3, 0, 1));
	const __m128i y_abs_rev = _mm_shuffle_epi32(y_abs, _MM_SHUFFLE(2, 3, 0, 1));
	const __m128i z_abs_rev = _mm_shuffle_epi32(z_abs, _MM_SHUFFLE(2, 3, 0, 1));
	const __m128i w_abs_rev = _mm_shuffle_epi32(w_abs, _MM_SHUFFLE(2, 3, 0, 1));

	const __m128i x_abs_product_even = _mm_mul_epu32(x_abs, vmultiplier);
	const __m128i y_abs_product_even = _mm_mul_epu32(y_abs, vmultiplier);
	const __m128i z_abs_product_even = _mm_mul_epu32(z_abs, vmultiplier);
	const __m128i w_abs_product_even = _mm_mul_epu32(w_abs, vmultiplier);

	const __m128i x_neg_mask_even = _mm_shuffle_epi32(x_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));
	const __m128i y_neg_mask_even = _mm_shuffle_epi32(y_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));
	const __m128i z_neg_mask_even = _mm_shuffle_epi32(z_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));
	const __m128i w_neg_mask_even = _mm_shuffle_epi32(w_neg_mask, _MM_SHUFFLE(2, 2, 0, 0));

	const __m128i x_product_even = _mm_sub_epi64(_mm_xor_si128(x_abs_product_even, x_neg_mask_even), x_neg_mask_even);
	const __m128i y_product_even = _mm_sub_epi64(_mm_xor_si128(y_abs_product_even, y_neg_mask_even), y_neg_mask_even);
	const __m128i z_product_even = _mm_sub_epi64(_mm_xor_si128(z_abs_product_even, z_neg_mask_even), z_neg_mask_even);
	const __m128i w_product_even = _mm_sub_epi64(_mm_xor_si128(w_abs_product_even, w_neg_mask_even), w_neg_mask_even);

	const __m128i x_rounded_product_even = _mm_add_epi64(x_product_even, vq31rounding);
	const __m128i y_rounded_product_even = _mm_add_epi64(y_product_even, vq31rounding);
	const __m128i z_rounded_product_even = _mm_add_epi64(z_product_even, vq31rounding);
	const __m128i w_rounded_product_even = _mm_add_epi64(w_product_even, vq31rounding);

	const __m128i x_abs_product_odd = _mm_mul_epu32(x_abs_rev, vmultiplier);
	const __m128i y_abs_product_odd = _mm_mul_epu32(y_abs_rev, vmultiplier);
	const __m128i z_abs_product_odd = _mm_mul_epu32(z_abs_rev, vmultiplier);
	const __m128i w_abs_product_odd = _mm_mul_epu32(w_abs_rev, vmultiplier);

	const __m128i x_neg_mask_odd = _mm_shuffle_epi32(x_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));
	const __m128i y_neg_mask_odd = _mm_shuffle_epi32(y_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));
	const __m128i z_neg_mask_odd = _mm_shuffle_epi32(z_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));
	const __m128i w_neg_mask_odd = _mm_shuffle_epi32(w_neg_mask, _MM_SHUFFLE(3, 3, 1, 1));

	const __m128i x_product_odd = _mm_sub_epi64(_mm_xor_si128(x_abs_product_odd, x_neg_mask_odd), x_neg_mask_odd);
	const __m128i y_product_odd = _mm_sub_epi64(_mm_xor_si128(y_abs_product_odd, y_neg_mask_odd), y_neg_mask_odd);
	const __m128i z_product_odd = _mm_sub_epi64(_mm_xor_si128(z_abs_product_odd, z_neg_mask_odd), z_neg_mask_odd);
	const __m128i w_product_odd = _mm_sub_epi64(_mm_xor_si128(w_abs_product_odd, w_neg_mask_odd), w_neg_mask_odd);

	const __m128i x_rounded_product_odd = _mm_add_epi64(x_product_odd, vq31rounding);
	const __m128i y_rounded_product_odd = _mm_add_epi64(y_product_odd, vq31rounding);
	const __m128i z_rounded_product_odd = _mm_add_epi64(z_product_odd, vq31rounding);
	const __m128i w_rounded_product_odd = _mm_add_epi64(w_product_odd, vq31rounding);

	const __m128i x_q31product_even = _mm_srli_epi64(x_rounded_product_even, 31);
	const __m128i x_q31product_odd = _mm_srli_epi64(x_rounded_product_odd, 31);
	const __m128i y_q31product_even = _mm_srli_epi64(y_rounded_product_even, 31);
	const __m128i y_q31product_odd = _mm_srli_epi64(y_rounded_product_odd, 31);
	const __m128i z_q31product_even = _mm_srli_epi64(z_rounded_product_even, 31);
	const __m128i z_q31product_odd = _mm_srli_epi64(z_rounded_product_odd, 31);
	const __m128i w_q31product_even = _mm_srli_epi64(w_rounded_product_even, 31);
	const __m128i w_q31product_odd = _mm_srli_epi64(w_rounded_product_odd, 31);

	const __m128i x_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
	_mm_castsi128_ps(x_q31product_even), _mm_castsi128_ps(x_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));
	const __m128i y_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
	_mm_castsi128_ps(y_q31product_even), _mm_castsi128_ps(y_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));
	const __m128i z_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
	_mm_castsi128_ps(z_q31product_even), _mm_castsi128_ps(z_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));
	const __m128i w_q31product_0213 = _mm_castps_si128(_mm_shuffle_ps(
	_mm_castsi128_ps(w_q31product_even), _mm_castsi128_ps(w_q31product_odd), _MM_SHUFFLE(2, 0, 2, 0)));

	const __m128i x_q31product = _mm_shuffle_epi32(x_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));
	const __m128i y_q31product = _mm_shuffle_epi32(y_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));
	const __m128i z_q31product = _mm_shuffle_epi32(z_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));
	const __m128i w_q31product = _mm_shuffle_epi32(w_q31product_0213, _MM_SHUFFLE(3, 1, 2, 0));

	const __m128i x_remainder =
	_mm_add_epi32(_mm_and_si128(x_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), x_q31product));
	const __m128i y_remainder =
	_mm_add_epi32(_mm_and_si128(y_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), y_q31product));
	const __m128i z_remainder =
	_mm_add_epi32(_mm_and_si128(z_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), z_q31product));
	const __m128i w_remainder =
	_mm_add_epi32(_mm_and_si128(w_q31product, vremainder_mask), _mm_cmpgt_epi32(_mm_setzero_si128(), w_q31product));

	const __m128i x_scaled =
	_mm_sub_epi32(_mm_sra_epi32(x_q31product, vshift), _mm_cmpgt_epi32(x_remainder, vthreshold));
	const __m128i y_scaled =
	_mm_sub_epi32(_mm_sra_epi32(y_q31product, vshift), _mm_cmpgt_epi32(y_remainder, vthreshold));
	const __m128i z_scaled =
	_mm_sub_epi32(_mm_sra_epi32(z_q31product, vshift), _mm_cmpgt_epi32(z_remainder, vthreshold));
	const __m128i w_scaled =
	_mm_sub_epi32(_mm_sra_epi32(w_q31product, vshift), _mm_cmpgt_epi32(w_remainder, vthreshold));

	const __m128i xy_packed = _mm_adds_epi16(_mm_packs_epi32(x_scaled, y_scaled), vzero_point);
	const __m128i zw_packed = _mm_adds_epi16(_mm_packs_epi32(z_scaled, w_scaled), vzero_point);
	const __m128i xyzw_packed = _mm_packus_epi16(xy_packed, zw_packed);
	const __m128i xyzw_clamped = _mm_max_epu8(_mm_min_epu8(xyzw_packed, vqmax), vqmin);

	// 16x PSHUFD
	// 4x SHUFPS
	// 8x PMULUDQ
	// 8x PXOR (setzero)
	// 8x PXOR
	// 4x PAND
	// 8x PADDQ
	// 4x PADDD
	// 2x PADDW
	// 8x PSUBQ
	// 4x PSUBD
	// 8x PSRLQ (immediate)
	// 4x PSRAD (register)
	// 12x PCMPGTD
	// 4x PABSD
	// 2x PACKSSDW
	// 1x PACKUSWB
	// 1x PMAXUB
	// 1x PMINUB
	// ---------------------
	// 107 instructions total

	_mm_storeu_si128((__m128i*) output, xyzw_clamped);
	output += 16;
	}
	}