1 /*
2 * Copyright 2021 Google LLC
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include <cassert>
9 #include <cstdio>
10 #include <cstdint>
11 #include "experimental/lowp-basic/QMath.h"
12
13 // Compile for x86_64 + ssse3 with:
14 // c++ -O3 --std=c++17 -mssse3 experimental/lowp-basic/lowp_experiments.cpp -o lowp
15 //
16 // Compile for aarch64 with (Mac os):
17 // c++ -O3 --std=c++17 -arch arm64 experimental/lowp-basic/lowp_experiments.cpp -o lowp
18 //
19 // View assembly:
20 // dumpobj -d lowp | less
21
22 template <int N, typename T> using V = T __attribute__((ext_vector_type(N)));
23
24 #if !defined(__clang__)
25 static_assert(false, "This only works on clang.");
26 #endif
27
28 #if defined(__SSSE3__)
29 #include <immintrin.h>
30 #endif
31
32 #if defined(__ARM_NEON)
33 // From section 5.5.5 of the ARM C Language Extensions (ACLE)
34 #include <arm_neon.h>
35 #endif
36
37 using Q15 = V<8, uint16_t>;
38
39 #if defined(__SSSE3__)
test_mm_mulhrs_epi16_simulation()40 static void test_mm_mulhrs_epi16_simulation() {
41 for (int i = -32768; i < 32768; i++) {
42 for (int j = -32768; j < 32768; j++) {
43 Q15 a(i);
44 Q15 b(j);
45 Q15 simResult = simulate_ssse3_mm_mulhrs_epi16(a, b);
46 Q15 intrinsicResult = _mm_mulhrs_epi16(a, b);
47 for (int i = 0; i < 8; i++) {
48 if (simResult[i] != intrinsicResult[i]) {
49 printf("simulate_ssse3_mm_mulhrs_epi16 broken\n");
50 printf("i: %d, a: %hx b: %hx, intrinsic: %hx, sim: %hx\n",
51 i, a[i], b[i], intrinsicResult[i], simResult[i]);
52 exit(1);
53 }
54 }
55 }
56 }
57 }
58
59 // Use ssse3 to simulate saturating multiply on arm.
ssse3_vqrdmulhq_s16(Q15 a,Q15 b)60 static Q15 ssse3_vqrdmulhq_s16(Q15 a, Q15 b) {
61 constexpr Q15 limit(0x8000);
62 const Q15 product = _mm_mulhrs_epi16(a, b);
63 const Q15 eq = _mm_cmpeq_epi16(product, limit);
64 return _mm_xor_si128(eq, product);
65 }
66
test_ssse3_vqrdmulhq_s16()67 static void test_ssse3_vqrdmulhq_s16() {
68 for (int i = -32768; i < 32768; i++) {
69 for (int j = -32768; j < 32768; j++) {
70 Q15 a(i);
71 Q15 b(j);
72 Q15 simResult = ssse3_vqrdmulhq_s16(a, b);
73 Q15 realVqrdmulhqS16 = simulate_neon_vqrdmulhq_s16(a, b);
74 for (int i = 0; i < 8; i++) {
75 if (simResult[i] != realVqrdmulhqS16[i]) {
76 printf("simulating vqrdmulhq_s16 with ssse3 broken\n");
77 printf("i: %d, a: %hx b: %hx, intrinsic: %hx, sim: %hx\n",
78 i, a[i], b[i], realVqrdmulhqS16[i], simResult[i]);
79 exit(1);
80 }
81 }
82 }
83 }
84 }
85
86 #endif
87
88 #if defined(__ARM_NEON)
test_neon_vqrdmulhq_s16_simulation()89 static void test_neon_vqrdmulhq_s16_simulation() {
90 for (int i = -32768; i < 32768; i++) {
91 for (int j = -32768; j < 32768; j++) {
92 Q15 a(i);
93 Q15 b(j);
94 Q15 simResult = simulate_neon_vqrdmulhq_s16(a, b);
95 Q15 intrinsicResult = vqrdmulhq_s16(a, b);
96 for (int i = 0; i < 8; i++) {
97 if (simResult[i] != intrinsicResult[i]) {
98 printf("simulate_neon_vqrdmulhq_s16 broken\n");
99 printf("i: %d, a: %hx b: %hx, intrinsic: %hx, sim: %hx\n",
100 i, a[i], b[i], intrinsicResult[i], simResult[i]);
101 exit(1);
102 }
103 }
104 }
105 }
106 }
107 #endif
108
main()109 int main() {
110 #if defined(__SSSE3__)
111 //test_mm_mulhrs_epi16_simulation();
112 test_ssse3_vqrdmulhq_s16();
113 #endif
114 #if defined(__ARM_NEON)
115 test_neon_vqrdmulhq_s16_simulation();
116 #endif
117 printf("Done.\n");
118 return 0;
119 }
120