diff options
Diffstat (limited to 'pl/math/log.c')
| -rw-r--r-- | pl/math/log.c | 161 |
1 files changed, 0 insertions, 161 deletions
diff --git a/pl/math/log.c b/pl/math/log.c deleted file mode 100644 index 40b0441d981d..000000000000 --- a/pl/math/log.c +++ /dev/null @@ -1,161 +0,0 @@ -/* - * Double-precision log(x) function. - * - * Copyright (c) 2018-2023, Arm Limited. - * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception - */ - -#include <float.h> -#include <math.h> -#include <stdint.h> -#include "math_config.h" - -#define T __log_data.tab -#define T2 __log_data.tab2 -#define B __log_data.poly1 -#define A __log_data.poly -#define Ln2hi __log_data.ln2hi -#define Ln2lo __log_data.ln2lo -#define N (1 << LOG_TABLE_BITS) -#define OFF 0x3fe6000000000000 - -/* Top 16 bits of a double. */ -static inline uint32_t -top16 (double x) -{ - return asuint64 (x) >> 48; -} - -double -optr_aor_log_f64 (double x) -{ - /* double_t for better performance on targets with FLT_EVAL_METHOD==2. */ - double_t w, z, r, r2, r3, y, invc, logc, kd, hi, lo; - uint64_t ix, iz, tmp; - uint32_t top; - int k, i; - - ix = asuint64 (x); - top = top16 (x); - -#if LOG_POLY1_ORDER == 10 || LOG_POLY1_ORDER == 11 -#define LO asuint64 (1.0 - 0x1p-5) -#define HI asuint64 (1.0 + 0x1.1p-5) -#elif LOG_POLY1_ORDER == 12 -#define LO asuint64 (1.0 - 0x1p-4) -#define HI asuint64 (1.0 + 0x1.09p-4) -#endif - if (unlikely (ix - LO < HI - LO)) - { - /* Handle close to 1.0 inputs separately. */ - /* Fix sign of zero with downward rounding when x==1. */ - if (WANT_ROUNDING && unlikely (ix == asuint64 (1.0))) - return 0; - r = x - 1.0; - r2 = r * r; - r3 = r * r2; -#if LOG_POLY1_ORDER == 10 - /* Worst-case error is around 0.516 ULP. */ - y = r3 - * (B[1] + r * B[2] + r2 * B[3] - + r3 * (B[4] + r * B[5] + r2 * B[6] + r3 * (B[7] + r * B[8]))); - w = B[0] * r2; /* B[0] == -0.5. */ - hi = r + w; - y += r - hi + w; - y += hi; -#elif LOG_POLY1_ORDER == 11 - /* Worst-case error is around 0.516 ULP. */ - y = r3 - * (B[1] + r * B[2] - + r2 - * (B[3] + r * B[4] + r2 * B[5] - + r3 * (B[6] + r * B[7] + r2 * B[8] + r3 * B[9]))); - w = B[0] * r2; /* B[0] == -0.5. */ - hi = r + w; - y += r - hi + w; - y += hi; -#elif LOG_POLY1_ORDER == 12 - y = r3 - * (B[1] + r * B[2] + r2 * B[3] - + r3 - * (B[4] + r * B[5] + r2 * B[6] - + r3 * (B[7] + r * B[8] + r2 * B[9] + r3 * B[10]))); -#if N <= 64 - /* Worst-case error is around 0.532 ULP. */ - w = B[0] * r2; /* B[0] == -0.5. */ - hi = r + w; - y += r - hi + w; - y += hi; -#else - /* Worst-case error is around 0.507 ULP. */ - w = r * 0x1p27; - double_t rhi = r + w - w; - double_t rlo = r - rhi; - w = rhi * rhi * B[0]; /* B[0] == -0.5. */ - hi = r + w; - lo = r - hi + w; - lo += B[0] * rlo * (rhi + r); - y += lo; - y += hi; -#endif -#endif - return eval_as_double (y); - } - if (unlikely (top - 0x0010 >= 0x7ff0 - 0x0010)) - { - /* x < 0x1p-1022 or inf or nan. */ - if (ix * 2 == 0) - return __math_divzero (1); - if (ix == asuint64 (INFINITY)) /* log(inf) == inf. */ - return x; - if ((top & 0x8000) || (top & 0x7ff0) == 0x7ff0) - return __math_invalid (x); - /* x is subnormal, normalize it. */ - ix = asuint64 (x * 0x1p52); - ix -= 52ULL << 52; - } - - /* 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 = ix - OFF; - i = (tmp >> (52 - LOG_TABLE_BITS)) % N; - k = (int64_t) tmp >> 52; /* arithmetic shift */ - iz = ix - (tmp & 0xfffULL << 52); - invc = T[i].invc; - logc = T[i].logc; - z = asdouble (iz); - - /* log(x) = log1p(z/c-1) + log(c) + k*Ln2. */ - /* r ~= z/c - 1, |r| < 1/(2*N). */ -#if HAVE_FAST_FMA - /* rounding error: 0x1p-55/N. */ - r = fma (z, invc, -1.0); -#else - /* rounding error: 0x1p-55/N + 0x1p-66. */ - r = (z - T2[i].chi - T2[i].clo) * invc; -#endif - kd = (double_t) k; - - /* hi + lo = r + log(c) + k*Ln2. */ - w = kd * Ln2hi + logc; - hi = w + r; - lo = w - hi + r + kd * Ln2lo; - - /* log(x) = lo + (log1p(r) - r) + hi. */ - r2 = r * r; /* rounding error: 0x1p-54/N^2. */ - /* Worst case error if |y| > 0x1p-5: - 0.5 + 4.13/N + abs-poly-error*2^57 ULP (+ 0.002 ULP without fma) - Worst case error if |y| > 0x1p-4: - 0.5 + 2.06/N + abs-poly-error*2^56 ULP (+ 0.001 ULP without fma). */ -#if LOG_POLY_ORDER == 6 - y = lo + r2 * A[0] + r * r2 * (A[1] + r * A[2] + r2 * (A[3] + r * A[4])) + hi; -#elif LOG_POLY_ORDER == 7 - y = lo - + r2 - * (A[0] + r * A[1] + r2 * (A[2] + r * A[3]) - + r2 * r2 * (A[4] + r * A[5])) - + hi; -#endif - return eval_as_double (y); -} |