diff options
Diffstat (limited to 'math/aarch64/v_log.c')
| -rw-r--r-- | math/aarch64/v_log.c | 100 |
1 files changed, 0 insertions, 100 deletions
diff --git a/math/aarch64/v_log.c b/math/aarch64/v_log.c deleted file mode 100644 index 1d1c1fa62c04..000000000000 --- a/math/aarch64/v_log.c +++ /dev/null @@ -1,100 +0,0 @@ -/* - * Double-precision vector log(x) function. - * - * Copyright (c) 2019-2023, Arm Limited. - * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception - */ - -#include "mathlib.h" -#include "v_math.h" - -static const struct data -{ - uint64x2_t min_norm; - uint32x4_t special_bound; - float64x2_t poly[5]; - float64x2_t ln2; - uint64x2_t sign_exp_mask; -} data = { - /* Worst-case error: 1.17 + 0.5 ulp. - Rel error: 0x1.6272e588p-56 in [ -0x1.fc1p-9 0x1.009p-8 ]. */ - .poly = { V2 (-0x1.ffffffffffff7p-2), V2 (0x1.55555555170d4p-2), - V2 (-0x1.0000000399c27p-2), V2 (0x1.999b2e90e94cap-3), - V2 (-0x1.554e550bd501ep-3) }, - .ln2 = V2 (0x1.62e42fefa39efp-1), - .min_norm = V2 (0x0010000000000000), - .special_bound = V4 (0x7fe00000), /* asuint64(inf) - min_norm. */ - .sign_exp_mask = V2 (0xfff0000000000000) -}; - -#define A(i) d->poly[i] -#define N (1 << V_LOG_TABLE_BITS) -#define IndexMask (N - 1) -#define Off v_u64 (0x3fe6900900000000) - -struct entry -{ - float64x2_t invc; - float64x2_t logc; -}; - -static inline struct entry -lookup (uint64x2_t i) -{ - /* Since N is a power of 2, n % N = n & (N - 1). */ - struct entry e; - uint64_t i0 = (i[0] >> (52 - V_LOG_TABLE_BITS)) & IndexMask; - uint64_t i1 = (i[1] >> (52 - V_LOG_TABLE_BITS)) & IndexMask; - float64x2_t e0 = vld1q_f64 (&__v_log_data.table[i0].invc); - float64x2_t e1 = vld1q_f64 (&__v_log_data.table[i1].invc); - e.invc = vuzp1q_f64 (e0, e1); - e.logc = vuzp2q_f64 (e0, e1); - return e; -} - -static float64x2_t VPCS_ATTR NOINLINE -special_case (float64x2_t x, float64x2_t y, float64x2_t hi, float64x2_t r2, - uint32x2_t cmp) -{ - return v_call_f64 (log, x, vfmaq_f64 (hi, y, r2), vmovl_u32 (cmp)); -} - -float64x2_t VPCS_ATTR V_NAME_D1 (log) (float64x2_t x) -{ - const struct data *d = ptr_barrier (&data); - float64x2_t z, r, r2, p, y, kd, hi; - uint64x2_t ix, iz, tmp; - uint32x2_t cmp; - int64x2_t k; - struct entry e; - - ix = vreinterpretq_u64_f64 (x); - cmp = vcge_u32 (vsubhn_u64 (ix, d->min_norm), - vget_low_u32 (d->special_bound)); - - /* x = 2^k z; where z is in range [Off,2*Off) and exact. - The range is split into N subintervals. - The ith subinterval contains z and c is near its center. */ - tmp = vsubq_u64 (ix, Off); - k = vshrq_n_s64 (vreinterpretq_s64_u64 (tmp), 52); /* arithmetic shift. */ - iz = vsubq_u64 (ix, vandq_u64 (tmp, d->sign_exp_mask)); - z = vreinterpretq_f64_u64 (iz); - e = lookup (tmp); - - /* log(x) = log1p(z/c-1) + log(c) + k*Ln2. */ - r = vfmaq_f64 (v_f64 (-1.0), z, e.invc); - kd = vcvtq_f64_s64 (k); - - /* hi = r + log(c) + k*Ln2. */ - hi = vfmaq_f64 (vaddq_f64 (e.logc, r), kd, d->ln2); - /* y = r2*(A0 + r*A1 + r2*(A2 + r*A3 + r2*A4)) + hi. */ - r2 = vmulq_f64 (r, r); - y = vfmaq_f64 (A (2), A (3), r); - p = vfmaq_f64 (A (0), A (1), r); - y = vfmaq_f64 (y, A (4), r2); - y = vfmaq_f64 (p, y, r2); - - if (unlikely (v_any_u32h (cmp))) - return special_case (x, y, hi, r2, cmp); - return vfmaq_f64 (hi, y, r2); -} |
