1 // Copyright 2021 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 #include <assert.h>
7 #include <stddef.h>
8 #include <stdint.h>
9
10 #include <wasm_simd128.h>
11
12 #include <xnnpack/math-stubs.h>
13
14
xnn_math_f16_f32_cvt__wasmsimd_int16(size_t n,const void * input,float * output)15 void xnn_math_f16_f32_cvt__wasmsimd_int16(
16 size_t n,
17 const void* input,
18 float* output)
19 {
20 assert(n % (8 * sizeof(float)) == 0);
21
22 const v128_t vsign_mask = wasm_i16x8_const_splat(0x8000);
23 const v128_t vexp_offset = wasm_i16x8_const_splat(0x7000);
24 const v128_t vexp_scale = wasm_f32x4_const_splat(0x1.0p-112f);
25 const v128_t vmagic_mask = wasm_i16x8_const_splat(0x3F00);
26 const v128_t vmagic_bias = wasm_f32x4_const_splat(0.5f);
27 const v128_t vdenorm_cutoff = wasm_i16x8_const_splat(0x0400);
28
29 const uint16_t* i = (const uint16_t*) input;
30 for (; n != 0; n -= 8 * sizeof(float)) {
31 const v128_t vh = wasm_v128_load(i);
32 i += 8;
33
34 const v128_t vsign = wasm_v128_and(vh, vsign_mask);
35
36 const v128_t vnonsign = wasm_v128_xor(vh, vsign);
37
38 const v128_t vprenorm_lo = wasm_i16x8_shl(vnonsign, 13);
39 const v128_t vprenorm_hi = wasm_i16x8_add(wasm_u16x8_shr(vnonsign, 3), vexp_offset);
40
41 const v128_t vnorm_lo = wasm_f32x4_mul(wasm_v16x8_shuffle(vprenorm_lo, vprenorm_hi, 0, 8, 1, 9, 2, 10, 3, 11), vexp_scale);
42 const v128_t vnorm_hi = wasm_f32x4_mul(wasm_v16x8_shuffle(vprenorm_lo, vprenorm_hi, 4, 12, 5, 13, 6, 14, 7, 15), vexp_scale);
43
44 const v128_t vdenorm_lo = wasm_f32x4_sub(wasm_v16x8_shuffle(vnonsign, vmagic_mask, 0, 8, 1, 9, 2, 10, 3, 11), vmagic_bias);
45 const v128_t vdenorm_hi = wasm_f32x4_sub(wasm_v16x8_shuffle(vnonsign, vmagic_mask, 4, 12, 5, 13, 6, 14, 7, 15), vmagic_bias);
46
47 const v128_t vmask = wasm_i16x8_gt(vnonsign, vdenorm_cutoff);
48 const v128_t vmask_lo = wasm_i32x4_extend_low_i16x8(vmask);
49 const v128_t vmask_hi = wasm_i32x4_extend_high_i16x8(vmask);
50
51 const v128_t vzero = wasm_i16x8_const_splat(0);
52 const v128_t vf_lo = wasm_v128_or(wasm_v16x8_shuffle(vzero, vsign, 0, 8, 1, 9, 2, 10, 3, 11),
53 wasm_v128_bitselect(vnorm_lo, vdenorm_lo, vmask_lo));
54 const v128_t vf_hi = wasm_v128_or(wasm_v16x8_shuffle(vzero, vsign, 4, 12, 5, 13, 6, 14, 7, 15),
55 wasm_v128_bitselect(vnorm_hi, vdenorm_hi, vmask_hi));
56
57 wasm_v128_store(output, vf_lo);
58 wasm_v128_store(output + 4, vf_hi);
59 output += 8;
60 }
61 }
62