1*f3087befSAndrew Turner /* 2*f3087befSAndrew Turner * Single-precision vector exp(x) - 1 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 #include "v_expm1f_inline.h" 12*f3087befSAndrew Turner 13*f3087befSAndrew Turner static const struct data 14*f3087befSAndrew Turner { 15*f3087befSAndrew Turner struct v_expm1f_data d; 16*f3087befSAndrew Turner #if WANT_SIMD_EXCEPT 17*f3087befSAndrew Turner uint32x4_t thresh; 18*f3087befSAndrew Turner #else 19*f3087befSAndrew Turner float32x4_t oflow_bound; 20*f3087befSAndrew Turner #endif 21*f3087befSAndrew Turner } data = { 22*f3087befSAndrew Turner .d = V_EXPM1F_DATA, 23*f3087befSAndrew Turner #if !WANT_SIMD_EXCEPT 24*f3087befSAndrew Turner /* Value above which expm1f(x) should overflow. Absolute value of the 25*f3087befSAndrew Turner underflow bound is greater than this, so it catches both cases - there is 26*f3087befSAndrew Turner a small window where fallbacks are triggered unnecessarily. */ 27*f3087befSAndrew Turner .oflow_bound = V4 (0x1.5ebc4p+6), 28*f3087befSAndrew Turner #else 29*f3087befSAndrew Turner /* asuint(oflow_bound) - asuint(0x1p-23), shifted left by 1 for absolute 30*f3087befSAndrew Turner compare. */ 31*f3087befSAndrew Turner .thresh = V4 (0x1d5ebc40), 32*f3087befSAndrew Turner #endif 33*f3087befSAndrew Turner }; 34*f3087befSAndrew Turner 35*f3087befSAndrew Turner /* asuint(0x1p-23), shifted by 1 for abs compare. */ 36*f3087befSAndrew Turner #define TinyBound v_u32 (0x34000000 << 1) 37*f3087befSAndrew Turner 38*f3087befSAndrew Turner static float32x4_t VPCS_ATTR NOINLINE 39*f3087befSAndrew Turner special_case (float32x4_t x, uint32x4_t special, const struct data *d) 40*f3087befSAndrew Turner { 41*f3087befSAndrew Turner return v_call_f32 ( 42*f3087befSAndrew Turner expm1f, x, expm1f_inline (v_zerofy_f32 (x, special), &d->d), special); 43*f3087befSAndrew Turner } 44*f3087befSAndrew Turner 45*f3087befSAndrew Turner /* Single-precision vector exp(x) - 1 function. 46*f3087befSAndrew Turner The maximum error is 1.62 ULP: 47*f3087befSAndrew Turner _ZGVnN4v_expm1f(0x1.85f83p-2) got 0x1.da9f4p-2 48*f3087befSAndrew Turner want 0x1.da9f44p-2. */ 49*f3087befSAndrew Turner float32x4_t VPCS_ATTR NOINLINE V_NAME_F1 (expm1) (float32x4_t x) 50*f3087befSAndrew Turner { 51*f3087befSAndrew Turner const struct data *d = ptr_barrier (&data); 52*f3087befSAndrew Turner 53*f3087befSAndrew Turner #if WANT_SIMD_EXCEPT 54*f3087befSAndrew Turner uint32x4_t ix = vreinterpretq_u32_f32 (x); 55*f3087befSAndrew Turner /* If fp exceptions are to be triggered correctly, fall back to scalar for 56*f3087befSAndrew Turner |x| < 2^-23, |x| > oflow_bound, Inf & NaN. Add ix to itself for 57*f3087befSAndrew Turner shift-left by 1, and compare with thresh which was left-shifted offline - 58*f3087befSAndrew Turner this is effectively an absolute compare. */ 59*f3087befSAndrew Turner uint32x4_t special 60*f3087befSAndrew Turner = vcgeq_u32 (vsubq_u32 (vaddq_u32 (ix, ix), TinyBound), d->thresh); 61*f3087befSAndrew Turner #else 62*f3087befSAndrew Turner /* Handles very large values (+ve and -ve), +/-NaN, +/-Inf. */ 63*f3087befSAndrew Turner uint32x4_t special = vcagtq_f32 (x, d->oflow_bound); 64*f3087befSAndrew Turner #endif 65*f3087befSAndrew Turner 66*f3087befSAndrew Turner if (unlikely (v_any_u32 (special))) 67*f3087befSAndrew Turner return special_case (x, special, d); 68*f3087befSAndrew Turner 69*f3087befSAndrew Turner /* expm1(x) ~= p * t + (t - 1). */ 70*f3087befSAndrew Turner return expm1f_inline (x, &d->d); 71*f3087befSAndrew Turner } 72*f3087befSAndrew Turner 73*f3087befSAndrew Turner HALF_WIDTH_ALIAS_F1 (expm1) 74*f3087befSAndrew Turner 75*f3087befSAndrew Turner TEST_SIG (V, F, 1, expm1, -9.9, 9.9) 76*f3087befSAndrew Turner TEST_ULP (V_NAME_F1 (expm1), 1.13) 77*f3087befSAndrew Turner TEST_DISABLE_FENV_IF_NOT (V_NAME_F1 (expm1), WANT_SIMD_EXCEPT) 78*f3087befSAndrew Turner TEST_SYM_INTERVAL (V_NAME_F1 (expm1), 0, 0x1p-23, 1000) 79*f3087befSAndrew Turner TEST_INTERVAL (V_NAME_F1 (expm1), -0x1p-23, 0x1.5ebc4p+6, 1000000) 80*f3087befSAndrew Turner TEST_INTERVAL (V_NAME_F1 (expm1), -0x1p-23, -0x1.9bbabcp+6, 1000000) 81*f3087befSAndrew Turner TEST_INTERVAL (V_NAME_F1 (expm1), 0x1.5ebc4p+6, inf, 1000) 82*f3087befSAndrew Turner TEST_INTERVAL (V_NAME_F1 (expm1), -0x1.9bbabcp+6, -inf, 1000) 83