diff options
Diffstat (limited to 'sysdeps/aarch64/fpu/atan2f_advsimd.c')
| -rw-r--r-- | sysdeps/aarch64/fpu/atan2f_advsimd.c | 60 |
1 files changed, 35 insertions, 25 deletions
diff --git a/sysdeps/aarch64/fpu/atan2f_advsimd.c b/sysdeps/aarch64/fpu/atan2f_advsimd.c index 56e610c..e65406f 100644 --- a/sysdeps/aarch64/fpu/atan2f_advsimd.c +++ b/sysdeps/aarch64/fpu/atan2f_advsimd.c @@ -1,6 +1,6 @@ /* Single-precision AdvSIMD atan2 - Copyright (C) 2023-2024 Free Software Foundation, Inc. + Copyright (C) 2023-2025 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -22,34 +22,39 @@ static const struct data { - float32x4_t poly[8]; - float32x4_t pi_over_2; + float32x4_t c0, pi_over_2, c4, c6, c2; + float c1, c3, c5, c7; + uint32x4_t comp_const; } data = { /* Coefficients of polynomial P such that atan(x)~x+x*P(x^2) on [2**-128, 1.0]. Generated using fpminimax between FLT_MIN and 1. */ - .poly = { V4 (-0x1.55555p-2f), V4 (0x1.99935ep-3f), V4 (-0x1.24051ep-3f), - V4 (0x1.bd7368p-4f), V4 (-0x1.491f0ep-4f), V4 (0x1.93a2c0p-5f), - V4 (-0x1.4c3c60p-6f), V4 (0x1.01fd88p-8f) }, - .pi_over_2 = V4 (0x1.921fb6p+0f), + .c0 = V4 (-0x1.55555p-2f), .c1 = 0x1.99935ep-3f, + .c2 = V4 (-0x1.24051ep-3f), .c3 = 0x1.bd7368p-4f, + .c4 = V4 (-0x1.491f0ep-4f), .c5 = 0x1.93a2c0p-5f, + .c6 = V4 (-0x1.4c3c60p-6f), .c7 = 0x1.01fd88p-8f, + .pi_over_2 = V4 (0x1.921fb6p+0f), .comp_const = V4 (2 * 0x7f800000lu - 1), }; #define SignMask v_u32 (0x80000000) /* Special cases i.e. 0, infinity and nan (fall back to scalar calls). */ static float32x4_t VPCS_ATTR NOINLINE -special_case (float32x4_t y, float32x4_t x, float32x4_t ret, uint32x4_t cmp) +special_case (float32x4_t y, float32x4_t x, float32x4_t ret, + uint32x4_t sign_xy, uint32x4_t cmp) { + /* Account for the sign of y. */ + ret = vreinterpretq_f32_u32 ( + veorq_u32 (vreinterpretq_u32_f32 (ret), sign_xy)); return v_call2_f32 (atan2f, y, x, ret, cmp); } /* Returns 1 if input is the bit representation of 0, infinity or nan. */ static inline uint32x4_t -zeroinfnan (uint32x4_t i) +zeroinfnan (uint32x4_t i, const struct data *d) { /* 2 * i - 1 >= 2 * 0x7f800000lu - 1. */ - return vcgeq_u32 (vsubq_u32 (vmulq_n_u32 (i, 2), v_u32 (1)), - v_u32 (2 * 0x7f800000lu - 1)); + return vcgeq_u32 (vsubq_u32 (vmulq_n_u32 (i, 2), v_u32 (1)), d->comp_const); } /* Fast implementation of vector atan2f. Maximum observed error is @@ -58,12 +63,13 @@ zeroinfnan (uint32x4_t i) want 0x1.967f00p-1. */ float32x4_t VPCS_ATTR NOINLINE V_NAME_F2 (atan2) (float32x4_t y, float32x4_t x) { - const struct data *data_ptr = ptr_barrier (&data); + const struct data *d = ptr_barrier (&data); uint32x4_t ix = vreinterpretq_u32_f32 (x); uint32x4_t iy = vreinterpretq_u32_f32 (y); - uint32x4_t special_cases = vorrq_u32 (zeroinfnan (ix), zeroinfnan (iy)); + uint32x4_t special_cases + = vorrq_u32 (zeroinfnan (ix, d), zeroinfnan (iy, d)); uint32x4_t sign_x = vandq_u32 (ix, SignMask); uint32x4_t sign_y = vandq_u32 (iy, SignMask); @@ -77,14 +83,14 @@ float32x4_t VPCS_ATTR NOINLINE V_NAME_F2 (atan2) (float32x4_t y, float32x4_t x) /* Set up z for call to atanf. */ float32x4_t n = vbslq_f32 (pred_aygtax, vnegq_f32 (ax), ay); - float32x4_t d = vbslq_f32 (pred_aygtax, ay, ax); - float32x4_t z = vdivq_f32 (n, d); + float32x4_t q = vbslq_f32 (pred_aygtax, ay, ax); + float32x4_t z = vdivq_f32 (n, q); /* Work out the correct shift. */ float32x4_t shift = vreinterpretq_f32_u32 ( vandq_u32 (pred_xlt0, vreinterpretq_u32_f32 (v_f32 (-2.0f)))); shift = vbslq_f32 (pred_aygtax, vaddq_f32 (shift, v_f32 (1.0f)), shift); - shift = vmulq_f32 (shift, data_ptr->pi_over_2); + shift = vmulq_f32 (shift, d->pi_over_2); /* Calculate the polynomial approximation. Use 2-level Estrin scheme for P(z^2) with deg(P)=7. However, @@ -96,23 +102,27 @@ float32x4_t VPCS_ATTR NOINLINE V_NAME_F2 (atan2) (float32x4_t y, float32x4_t x) float32x4_t z2 = vmulq_f32 (z, z); float32x4_t z4 = vmulq_f32 (z2, z2); - float32x4_t ret = vfmaq_f32 ( - v_pairwise_poly_3_f32 (z2, z4, data_ptr->poly), z4, - vmulq_f32 (z4, v_pairwise_poly_3_f32 (z2, z4, data_ptr->poly + 4))); + float32x4_t c1357 = vld1q_f32 (&d->c1); + float32x4_t p01 = vfmaq_laneq_f32 (d->c0, z2, c1357, 0); + float32x4_t p23 = vfmaq_laneq_f32 (d->c2, z2, c1357, 1); + float32x4_t p45 = vfmaq_laneq_f32 (d->c4, z2, c1357, 2); + float32x4_t p67 = vfmaq_laneq_f32 (d->c6, z2, c1357, 3); + float32x4_t p03 = vfmaq_f32 (p01, z4, p23); + float32x4_t p47 = vfmaq_f32 (p45, z4, p67); + + float32x4_t ret = vfmaq_f32 (p03, z4, vmulq_f32 (z4, p47)); /* y = shift + z * P(z^2). */ ret = vaddq_f32 (vfmaq_f32 (z, ret, vmulq_f32 (z2, z)), shift); - /* Account for the sign of y. */ - ret = vreinterpretq_f32_u32 ( - veorq_u32 (vreinterpretq_u32_f32 (ret), sign_xy)); - if (__glibc_unlikely (v_any_u32 (special_cases))) { - return special_case (y, x, ret, special_cases); + return special_case (y, x, ret, sign_xy, special_cases); } - return ret; + /* Account for the sign of y. */ + return vreinterpretq_f32_u32 ( + veorq_u32 (vreinterpretq_u32_f32 (ret), sign_xy)); } libmvec_hidden_def (V_NAME_F2 (atan2)) HALF_WIDTH_ALIAS_F2(atan2) |