1// Copyright 2020 Google LLC
2//
3// This source code is licensed under the BSD-style license found in the
4// LICENSE file in the root directory of this source tree.
5
6$assert BATCH_TILE % 8 == 0
7$assert BATCH_TILE >= 8
8$SIMD_TILE = BATCH_TILE // 8
9#include <assert.h>
10
11#include <immintrin.h>
12
13#include <xnnpack/common.h>
14#include <xnnpack/vunary.h>
15
16
17static const int32_t mask_table[14] = {-1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0};
18
19void xnn_f32_velu_ukernel__avx2_rr1_lut4_p4_perm_x${BATCH_TILE}(
20    size_t n,
21    const float* x,
22    float* y,
23    const union xnn_f32_elu_params params[restrict XNN_MIN_ELEMENTS(1)])
24{
25  assert(n % sizeof(float) == 0);
26
27  const __m256 vprescale = _mm256_broadcast_ps((const __m128*) params->sse.prescale);
28  const __m256 valpha = _mm256_broadcast_ps((const __m128*) params->sse.alpha);
29  const __m256 vbeta = _mm256_broadcast_ps((const __m128*) params->sse.beta);
30
31  const __m256 vsat_cutoff = _mm256_set1_ps(-0x1.154246p+4f);
32  const __m256 vmagic_bias = _mm256_set1_ps(0x1.800000p21f);
33  const __m256 vlog2e = _mm256_set1_ps(0x1.715476p+0f);
34  const __m256 vtable = _mm256_set_ps(
35    0x1.EE89FAp-1f, 0x1.EA09E6p-1f, 0x1.F06FE0p-1f, 0x1.000000p+0f,
36    0x1.EE89FAp-1f, 0x1.EA09E6p-1f, 0x1.F06FE0p-1f, 0x1.000000p+0f);
37  const __m256 vminus_ln2 = _mm256_set1_ps(-0x1.62E43p-1f);
38  const __m256 vc4 = _mm256_set1_ps(0x1.554F9Ap-5f);
39  const __m256 vc3 = _mm256_set1_ps(0x1.557082p-3f);
40  const __m256 vc2 = _mm256_set1_ps(0x1.000002p-1f);
41
42  $if BATCH_TILE > 8:
43    for (; n >= ${BATCH_TILE} * sizeof(float); n -= ${BATCH_TILE} * sizeof(float)) {
44      __m256 vx0 = _mm256_loadu_ps(x);
45      $for N in range(1, SIMD_TILE):
46        __m256 vx${N} = _mm256_loadu_ps(x + ${N * 8});
47      x += ${BATCH_TILE};
48
49      $for N in range(SIMD_TILE):
50        const __m256 vz${N} = _mm256_max_ps(vsat_cutoff, _mm256_mul_ps(vx${N}, vprescale));
51
52      $for N in range(SIMD_TILE):
53        __m256 vn${N} = _mm256_fmadd_ps(vz${N}, vlog2e, vmagic_bias);
54
55      $for N in range(SIMD_TILE):
56        const __m256i ven${N} = _mm256_slli_epi32(_mm256_castps_si256(vn${N}), 21);
57        const __m256i vl${N} = _mm256_castps_si256(_mm256_permutevar_ps(vtable, _mm256_castps_si256(vn${N})));
58        vn${N} = _mm256_sub_ps(vn${N}, vmagic_bias);
59
60      $for N in range(SIMD_TILE):
61        __m256 vs${N} = _mm256_castsi256_ps(_mm256_add_epi32(vl${N}, ven${N}));
62        __m256 vt${N} = _mm256_fmadd_ps(vn${N}, vminus_ln2, vz${N});
63
64      $for N in range(SIMD_TILE):
65        __m256 vp${N} = _mm256_fmadd_ps(vc4, vt${N}, vc3);
66
67      $for N in range(SIMD_TILE):
68        vp${N} = _mm256_fmadd_ps(vp${N}, vt${N}, vc2);
69
70      $for N in range(SIMD_TILE):
71        vp${N} = _mm256_mul_ps(vp${N}, vt${N});
72        vt${N} = _mm256_mul_ps(vt${N}, vs${N});
73
74      $for N in range(SIMD_TILE):
75        vs${N} = _mm256_fmsub_ps(vs${N}, valpha, valpha);
76        vp${N} = _mm256_fmadd_ps(vp${N}, vt${N}, vt${N});
77
78      $for N in range(SIMD_TILE):
79        const __m256 ve${N} = _mm256_fmadd_ps(vp${N}, valpha, vs${N});
80        vx${N} = _mm256_mul_ps(vx${N}, vbeta);
81
82      $for N in range(SIMD_TILE):
83        const __m256 vy${N} = _mm256_blendv_ps(vx${N}, ve${N}, vx${N});
84
85      _mm256_storeu_ps(y, vy0);
86      $for N in range(1, SIMD_TILE):
87        _mm256_storeu_ps(y + ${N * 8}, vy${N});
88      y += ${BATCH_TILE};
89    }
90  for (; n >= 8 * sizeof(float); n -= 8 * sizeof(float)) {
91    __m256 vx = _mm256_loadu_ps(x);
92    x += 8;
93
94    const __m256 vz = _mm256_max_ps(vsat_cutoff, _mm256_mul_ps(vx, vprescale));
95
96    __m256 vn = _mm256_fmadd_ps(vz, vlog2e, vmagic_bias);
97    const __m256i ven = _mm256_slli_epi32(_mm256_castps_si256(vn), 21);
98    const __m256i vl = _mm256_castps_si256(_mm256_permutevar_ps(vtable, _mm256_castps_si256(vn)));
99    __m256 vs = _mm256_castsi256_ps(_mm256_add_epi32(vl, ven));
100    vn = _mm256_sub_ps(vn, vmagic_bias);
101
102    __m256 vt = _mm256_fmadd_ps(vn, vminus_ln2, vz);
103
104    __m256 vp = _mm256_fmadd_ps(vc4, vt, vc3);
105    vp = _mm256_fmadd_ps(vp, vt, vc2);
106    vp = _mm256_mul_ps(vp, vt);
107
108    vt = _mm256_mul_ps(vt, vs);
109    vs = _mm256_fmsub_ps(vs, valpha, valpha);
110    vp = _mm256_fmadd_ps(vp, vt, vt);
111    const __m256 ve = _mm256_fmadd_ps(vp, valpha, vs);
112
113    vx = _mm256_mul_ps(vx, vbeta);
114    const __m256 vy = _mm256_blendv_ps(vx, ve, vx);
115
116    _mm256_storeu_ps(y, vy);
117    y += 8;
118  }
119  if XNN_UNLIKELY(n != 0) {
120    assert(n >= 1 * sizeof(float));
121    assert(n <= 7 * sizeof(float));
122    __m256i vmask = _mm256_loadu_si256((const __m256i*) ((uintptr_t) &mask_table[7] - n));
123
124    __m256 vx = _mm256_maskload_ps(x, vmask);
125
126    const __m256 vz = _mm256_max_ps(vsat_cutoff, _mm256_mul_ps(vx, vprescale));
127
128    __m256 vn = _mm256_fmadd_ps(vz, vlog2e, vmagic_bias);
129    const __m256i ven = _mm256_slli_epi32(_mm256_castps_si256(vn), 21);
130    const __m256i vl = _mm256_castps_si256(_mm256_permutevar_ps(vtable, _mm256_castps_si256(vn)));
131    __m256 vs = _mm256_castsi256_ps(_mm256_add_epi32(vl, ven));
132    vn = _mm256_sub_ps(vn, vmagic_bias);
133
134    __m256 vt = _mm256_fmadd_ps(vn, vminus_ln2, vz);
135
136    __m256 vp = _mm256_fmadd_ps(vc4, vt, vc3);
137    vp = _mm256_fmadd_ps(vp, vt, vc2);
138    vp = _mm256_mul_ps(vp, vt);
139
140    vt = _mm256_mul_ps(vt, vs);
141    vs = _mm256_fmsub_ps(vs, valpha, valpha);
142    vp = _mm256_fmadd_ps(vp, vt, vt);
143    const __m256 ve = _mm256_fmadd_ps(vp, valpha, vs);
144
145    vx = _mm256_mul_ps(vx, vbeta);
146    const __m256 vy = _mm256_blendv_ps(vx, ve, vx);
147
148    // _mm256_maskstore_ps(y, vmask, vf) could be used here, but triggers msan failures (probably an msan bug).
149    __m128 vy_lo = _mm256_castps256_ps128(vy);
150    if (n & (4 * sizeof(float))) {
151      _mm_storeu_ps(y, vy_lo);
152      vy_lo = _mm256_extractf128_ps(vy, 1);
153      y += 4;
154    }
155    if (n & (2 * sizeof(float))) {
156      _mm_storel_pi((__m64*) y, vy_lo);
157      vy_lo = _mm_movehl_ps(vy_lo, vy_lo);
158      y += 2;
159    }
160    if (n & (1 * sizeof(float))) {
161      _mm_store_ss(y, vy_lo);
162    }
163  }
164}
165