1*f3087befSAndrew Turner /* 2*f3087befSAndrew Turner * Double-precision vector atanh(x) function. 3*f3087befSAndrew Turner * 4*f3087befSAndrew Turner * Copyright (c) 2022-2024, Arm Limited. 5*f3087befSAndrew Turner * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception 6*f3087befSAndrew Turner */ 7*f3087befSAndrew Turner 8*f3087befSAndrew Turner #include "v_math.h" 9*f3087befSAndrew Turner #include "test_sig.h" 10*f3087befSAndrew Turner #include "test_defs.h" 11*f3087befSAndrew Turner 12*f3087befSAndrew Turner #define WANT_V_LOG1P_K0_SHORTCUT 0 13*f3087befSAndrew Turner #include "v_log1p_inline.h" 14*f3087befSAndrew Turner 15*f3087befSAndrew Turner const static struct data 16*f3087befSAndrew Turner { 17*f3087befSAndrew Turner struct v_log1p_data log1p_consts; 18*f3087befSAndrew Turner uint64x2_t one; 19*f3087befSAndrew Turner uint64x2_t sign_mask; 20*f3087befSAndrew Turner } data = { .log1p_consts = V_LOG1P_CONSTANTS_TABLE, 21*f3087befSAndrew Turner .one = V2 (0x3ff0000000000000), 22*f3087befSAndrew Turner .sign_mask = V2 (0x8000000000000000) }; 23*f3087befSAndrew Turner 24*f3087befSAndrew Turner static float64x2_t VPCS_ATTR NOINLINE 25*f3087befSAndrew Turner special_case (float64x2_t x, float64x2_t halfsign, float64x2_t y, 26*f3087befSAndrew Turner uint64x2_t special, const struct data *d) 27*f3087befSAndrew Turner { 28*f3087befSAndrew Turner y = log1p_inline (y, &d->log1p_consts); 29*f3087befSAndrew Turner return v_call_f64 (atanh, vbslq_f64 (d->sign_mask, halfsign, x), 30*f3087befSAndrew Turner vmulq_f64 (halfsign, y), special); 31*f3087befSAndrew Turner } 32*f3087befSAndrew Turner 33*f3087befSAndrew Turner /* Approximation for vector double-precision atanh(x) using modified log1p. 34*f3087befSAndrew Turner The greatest observed error is 3.31 ULP: 35*f3087befSAndrew Turner _ZGVnN2v_atanh(0x1.ffae6288b601p-6) got 0x1.ffd8ff31b5019p-6 36*f3087befSAndrew Turner want 0x1.ffd8ff31b501cp-6. */ 37*f3087befSAndrew Turner VPCS_ATTR 38*f3087befSAndrew Turner float64x2_t V_NAME_D1 (atanh) (float64x2_t x) 39*f3087befSAndrew Turner { 40*f3087befSAndrew Turner const struct data *d = ptr_barrier (&data); 41*f3087befSAndrew Turner 42*f3087befSAndrew Turner float64x2_t halfsign = vbslq_f64 (d->sign_mask, x, v_f64 (0.5)); 43*f3087befSAndrew Turner float64x2_t ax = vabsq_f64 (x); 44*f3087befSAndrew Turner uint64x2_t ia = vreinterpretq_u64_f64 (ax); 45*f3087befSAndrew Turner uint64x2_t special = vcgeq_u64 (ia, d->one); 46*f3087befSAndrew Turner 47*f3087befSAndrew Turner #if WANT_SIMD_EXCEPT 48*f3087befSAndrew Turner ax = v_zerofy_f64 (ax, special); 49*f3087befSAndrew Turner #endif 50*f3087befSAndrew Turner 51*f3087befSAndrew Turner float64x2_t y; 52*f3087befSAndrew Turner y = vaddq_f64 (ax, ax); 53*f3087befSAndrew Turner y = vdivq_f64 (y, vsubq_f64 (vreinterpretq_f64_u64 (d->one), ax)); 54*f3087befSAndrew Turner 55*f3087befSAndrew Turner if (unlikely (v_any_u64 (special))) 56*f3087befSAndrew Turner #if WANT_SIMD_EXCEPT 57*f3087befSAndrew Turner return special_case (x, halfsign, y, special, d); 58*f3087befSAndrew Turner #else 59*f3087befSAndrew Turner return special_case (ax, halfsign, y, special, d); 60*f3087befSAndrew Turner #endif 61*f3087befSAndrew Turner 62*f3087befSAndrew Turner y = log1p_inline (y, &d->log1p_consts); 63*f3087befSAndrew Turner return vmulq_f64 (y, halfsign); 64*f3087befSAndrew Turner } 65*f3087befSAndrew Turner 66*f3087befSAndrew Turner TEST_SIG (V, D, 1, atanh, -1.0, 1.0) 67*f3087befSAndrew Turner TEST_DISABLE_FENV_IF_NOT (V_NAME_D1 (atanh), WANT_SIMD_EXCEPT) 68*f3087befSAndrew Turner TEST_ULP (V_NAME_D1 (atanh), 3.32) 69*f3087befSAndrew Turner TEST_SYM_INTERVAL (V_NAME_D1 (atanh), 0, 0x1p-23, 10000) 70*f3087befSAndrew Turner TEST_SYM_INTERVAL (V_NAME_D1 (atanh), 0x1p-23, 1, 90000) 71*f3087befSAndrew Turner TEST_SYM_INTERVAL (V_NAME_D1 (atanh), 1, inf, 100) 72*f3087befSAndrew Turner /* atanh is asymptotic at 1, which is the default control value - have to set 73*f3087befSAndrew Turner -c 0 specially to ensure fp exceptions are triggered correctly (choice of 74*f3087befSAndrew Turner control lane is irrelevant if fp exceptions are disabled). */ 75*f3087befSAndrew Turner TEST_CONTROL_VALUE (V_NAME_D1 (atanh), 0) 76