1 /* 2 * Double-precision vector log(1+x) function. 3 * 4 * Copyright (c) 2022-2024, Arm Limited. 5 * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception 6 */ 7 8 #include "v_math.h" 9 #include "test_sig.h" 10 #include "test_defs.h" 11 12 #define WANT_V_LOG1P_K0_SHORTCUT 0 13 #include "v_log1p_inline.h" 14 15 const static struct data 16 { 17 struct v_log1p_data d; 18 uint64x2_t inf, minus_one; 19 } data = { .d = V_LOG1P_CONSTANTS_TABLE, 20 .inf = V2 (0x7ff0000000000000), 21 .minus_one = V2 (0xbff0000000000000) }; 22 23 #define BottomMask v_u64 (0xffffffff) 24 25 static float64x2_t NOINLINE VPCS_ATTR 26 special_case (float64x2_t x, uint64x2_t cmp, const struct data *d) 27 { 28 /* Side-step special lanes so fenv exceptions are not triggered 29 inadvertently. */ 30 float64x2_t x_nospecial = v_zerofy_f64 (x, cmp); 31 return v_call_f64 (log1p, x, log1p_inline (x_nospecial, &d->d), cmp); 32 } 33 34 /* Vector log1p approximation using polynomial on reduced interval. Routine is 35 a modification of the algorithm used in scalar log1p, with no shortcut for 36 k=0 and no narrowing for f and k. Maximum observed error is 2.45 ULP: 37 _ZGVnN2v_log1p(0x1.658f7035c4014p+11) got 0x1.fd61d0727429dp+2 38 want 0x1.fd61d0727429fp+2 . */ 39 VPCS_ATTR float64x2_t V_NAME_D1 (log1p) (float64x2_t x) 40 { 41 const struct data *d = ptr_barrier (&data); 42 uint64x2_t ix = vreinterpretq_u64_f64 (x); 43 uint64x2_t ia = vreinterpretq_u64_f64 (vabsq_f64 (x)); 44 45 uint64x2_t special_cases 46 = vorrq_u64 (vcgeq_u64 (ia, d->inf), vcgeq_u64 (ix, d->minus_one)); 47 48 if (unlikely (v_any_u64 (special_cases))) 49 return special_case (x, special_cases, d); 50 51 return log1p_inline (x, &d->d); 52 } 53 54 TEST_SIG (V, D, 1, log1p, -0.9, 10.0) 55 TEST_ULP (V_NAME_D1 (log1p), 1.95) 56 TEST_DISABLE_FENV_IF_NOT (V_NAME_D1 (log1p), WANT_SIMD_EXCEPT) 57 TEST_SYM_INTERVAL (V_NAME_D1 (log1p), 0.0, 0x1p-23, 50000) 58 TEST_SYM_INTERVAL (V_NAME_D1 (log1p), 0x1p-23, 0.001, 50000) 59 TEST_SYM_INTERVAL (V_NAME_D1 (log1p), 0.001, 1.0, 50000) 60 TEST_INTERVAL (V_NAME_D1 (log1p), 1, inf, 40000) 61 TEST_INTERVAL (V_NAME_D1 (log1p), -1.0, -inf, 500) 62