src/f32-vrnd/vrndne-neon.c.in

// Copyright 2020 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.

$assert BATCH_TILE % 4 == 0
$assert BATCH_TILE >= 4
$ABC = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#include <assert.h>

#include <arm_neon.h>

#include <xnnpack/common.h>
#include <xnnpack/math.h>
#include <xnnpack/vunary.h>


void xnn_f32_vrndne_ukernel__neon_x${BATCH_TILE}(
    size_t n,
    const float* x,
    float* y,
    const union xnn_f32_rnd_params params[restrict XNN_MIN_ELEMENTS(1)]) XNN_DISABLE_TSAN
{
  assert(n != 0);
  assert(n % sizeof(float) == 0);

  const float32x4_t vmagic_number = vreinterpretq_f32_u32(vmovq_n_u32(UINT32_C(0x4B000000)));
  for (; n >= ${BATCH_TILE} * sizeof(float); n -= ${BATCH_TILE} * sizeof(float)) {
    $for N in range(0, BATCH_TILE, 4):
      const float32x4_t vx${ABC[N:N+4]} = vld1q_f32(x); x += 4;

    $for N in range(0, BATCH_TILE, 4):
      const float32x4_t vabsx${ABC[N:N+4]} = vabsq_f32(vx${ABC[N:N+4]});
      uint32x4_t vrndmask${ABC[N:N+4]} = vcaltq_f32(vmagic_number, vx${ABC[N:N+4]});

    $for N in range(0, BATCH_TILE, 4):
      float32x4_t vrndabsx${ABC[N:N+4]} = vaddq_f32(vabsx${ABC[N:N+4]}, vmagic_number);

    $for N in range(0, BATCH_TILE, 4):
      vrndmask${ABC[N:N+4]} = vorrq_u32(vrndmask${ABC[N:N+4]}, vmovq_n_u32(UINT32_C(0x80000000)));

    $for N in range(0, BATCH_TILE, 4):
      vrndabsx${ABC[N:N+4]} = vsubq_f32(vrndabsx${ABC[N:N+4]}, vmagic_number);

    $for N in range(0, BATCH_TILE, 4):
      const float32x4_t vy${ABC[N:N+4]} = vbslq_f32(vrndmask${ABC[N:N+4]}, vx${ABC[N:N+4]}, vrndabsx${ABC[N:N+4]});

    $for N in range(0, BATCH_TILE, 4):
      vst1q_f32(y, vy${ABC[N:N+4]}); y += 4;
  }
  $if BATCH_TILE > 4:
    for (; n >= 4 * sizeof(float); n -= 4 * sizeof(float)) {
      const float32x4_t vx = vld1q_f32(x); x += 4;
      const float32x4_t vabsx = vabsq_f32(vx);
      uint32x4_t vrndmask = vcaltq_f32(vmagic_number, vx);
      float32x4_t vrndabsx = vaddq_f32(vabsx, vmagic_number);
      vrndmask = vorrq_u32(vrndmask, vmovq_n_u32(UINT32_C(0x80000000)));
      vrndabsx = vsubq_f32(vrndabsx, vmagic_number);
      const float32x4_t vy = vbslq_f32(vrndmask, vx, vrndabsx);
      vst1q_f32(y, vy); y += 4;
    }
  if XNN_UNLIKELY(n != 0) {
    const float32x4_t vx = vld1q_f32(x);
    const float32x4_t vabsx = vabsq_f32(vx);
    uint32x4_t vrndmask = vcaltq_f32(vmagic_number, vx);
    float32x4_t vrndabsx = vaddq_f32(vabsx, vmagic_number);
    vrndmask = vorrq_u32(vrndmask, vmovq_n_u32(UINT32_C(0x80000000)));
    vrndabsx = vsubq_f32(vrndabsx, vmagic_number);
    const float32x4_t vy = vbslq_f32(vrndmask, vx, vrndabsx);
    float32x2_t vy_lo = vget_low_f32(vy);
    if (n & (2 * sizeof(float))) {
      vst1_f32(y, vy_lo); y += 2;
      vy_lo = vget_high_f32(vy);
    }
    if (n & (1 * sizeof(float))) {
      vst1_lane_f32(y, vy_lo, 0);
    }
  }
}