1*f3087befSAndrew Turner /* 2*f3087befSAndrew Turner * Double-precision vector log(1+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 d; 18*f3087befSAndrew Turner uint64x2_t inf, minus_one; 19*f3087befSAndrew Turner } data = { .d = V_LOG1P_CONSTANTS_TABLE, 20*f3087befSAndrew Turner .inf = V2 (0x7ff0000000000000), 21*f3087befSAndrew Turner .minus_one = V2 (0xbff0000000000000) }; 22*f3087befSAndrew Turner 23*f3087befSAndrew Turner #define BottomMask v_u64 (0xffffffff) 24*f3087befSAndrew Turner 25*f3087befSAndrew Turner static float64x2_t NOINLINE VPCS_ATTR 26*f3087befSAndrew Turner special_case (float64x2_t x, uint64x2_t cmp, const struct data *d) 27*f3087befSAndrew Turner { 28*f3087befSAndrew Turner /* Side-step special lanes so fenv exceptions are not triggered 29*f3087befSAndrew Turner inadvertently. */ 30*f3087befSAndrew Turner float64x2_t x_nospecial = v_zerofy_f64 (x, cmp); 31*f3087befSAndrew Turner return v_call_f64 (log1p, x, log1p_inline (x_nospecial, &d->d), cmp); 32*f3087befSAndrew Turner } 33*f3087befSAndrew Turner 34*f3087befSAndrew Turner /* Vector log1p approximation using polynomial on reduced interval. Routine is 35*f3087befSAndrew Turner a modification of the algorithm used in scalar log1p, with no shortcut for 36*f3087befSAndrew Turner k=0 and no narrowing for f and k. Maximum observed error is 2.45 ULP: 37*f3087befSAndrew Turner _ZGVnN2v_log1p(0x1.658f7035c4014p+11) got 0x1.fd61d0727429dp+2 38*f3087befSAndrew Turner want 0x1.fd61d0727429fp+2 . */ 39*f3087befSAndrew Turner VPCS_ATTR float64x2_t V_NAME_D1 (log1p) (float64x2_t x) 40*f3087befSAndrew Turner { 41*f3087befSAndrew Turner const struct data *d = ptr_barrier (&data); 42*f3087befSAndrew Turner uint64x2_t ix = vreinterpretq_u64_f64 (x); 43*f3087befSAndrew Turner uint64x2_t ia = vreinterpretq_u64_f64 (vabsq_f64 (x)); 44*f3087befSAndrew Turner 45*f3087befSAndrew Turner uint64x2_t special_cases 46*f3087befSAndrew Turner = vorrq_u64 (vcgeq_u64 (ia, d->inf), vcgeq_u64 (ix, d->minus_one)); 47*f3087befSAndrew Turner 48*f3087befSAndrew Turner if (unlikely (v_any_u64 (special_cases))) 49*f3087befSAndrew Turner return special_case (x, special_cases, d); 50*f3087befSAndrew Turner 51*f3087befSAndrew Turner return log1p_inline (x, &d->d); 52*f3087befSAndrew Turner } 53*f3087befSAndrew Turner 54*f3087befSAndrew Turner TEST_SIG (V, D, 1, log1p, -0.9, 10.0) 55*f3087befSAndrew Turner TEST_ULP (V_NAME_D1 (log1p), 1.95) 56*f3087befSAndrew Turner TEST_DISABLE_FENV_IF_NOT (V_NAME_D1 (log1p), WANT_SIMD_EXCEPT) 57*f3087befSAndrew Turner TEST_SYM_INTERVAL (V_NAME_D1 (log1p), 0.0, 0x1p-23, 50000) 58*f3087befSAndrew Turner TEST_SYM_INTERVAL (V_NAME_D1 (log1p), 0x1p-23, 0.001, 50000) 59*f3087befSAndrew Turner TEST_SYM_INTERVAL (V_NAME_D1 (log1p), 0.001, 1.0, 50000) 60*f3087befSAndrew Turner TEST_INTERVAL (V_NAME_D1 (log1p), 1, inf, 40000) 61*f3087befSAndrew Turner TEST_INTERVAL (V_NAME_D1 (log1p), -1.0, -inf, 500) 62