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https://sourceware.org/git/glibc.git
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12b8dd7718
The commit 9247f53219 triggered some regressions on loongarch and
riscv:
math/test-float-log10
math/test-float32-log10
And it is due a wrong sync with CORE-MATH for special 0.0/-0.0
inputs.
Checked on aarch64-linux-gnu and loongarch64-linux-gnu-lp64d.
162 lines
6.3 KiB
C
162 lines
6.3 KiB
C
/* Correctly-rounded radix-10 logarithm function for binary32 value.
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Copyright (c) 2022-2023 Alexei Sibidanov.
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This file is part of the CORE-MATH project
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project (file src/binary32/log10/log10f.c, revision bc385c2).
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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#include <math.h>
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#include <stdint.h>
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#include <libm-alias-finite.h>
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#include "math_config.h"
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static __attribute__ ((noinline)) float
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as_special (float x)
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{
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uint32_t ux = asuint (x);
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if (ux == 0x7f800000u)
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return x; /* +inf */
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uint32_t ax = ux << 1;
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if (ax == 0u)
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/* -0.0 */
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return __math_divzerof (1);
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if (ax > 0xff000000u)
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return x + x; /* nan */
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return __math_invalidf (x);
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}
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float
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__ieee754_log10f (float x)
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{
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static const double tr[] =
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{
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0x1p+0, 0x1.f81f82p-1, 0x1.f07c1fp-1, 0x1.e9131acp-1,
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0x1.e1e1e1ep-1, 0x1.dae6077p-1, 0x1.d41d41dp-1, 0x1.cd85689p-1,
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0x1.c71c71cp-1, 0x1.c0e0704p-1, 0x1.bacf915p-1, 0x1.b4e81b5p-1,
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0x1.af286bdp-1, 0x1.a98ef6p-1, 0x1.a41a41ap-1, 0x1.9ec8e95p-1,
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0x1.999999ap-1, 0x1.948b0fdp-1, 0x1.8f9c19p-1, 0x1.8acb90fp-1,
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0x1.8618618p-1, 0x1.8181818p-1, 0x1.7d05f41p-1, 0x1.78a4c81p-1,
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0x1.745d174p-1, 0x1.702e05cp-1, 0x1.6c16c17p-1, 0x1.6816817p-1,
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0x1.642c859p-1, 0x1.605816p-1, 0x1.5c9882cp-1, 0x1.58ed231p-1,
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0x1.5555555p-1, 0x1.51d07ebp-1, 0x1.4e5e0a7p-1, 0x1.4afd6ap-1,
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0x1.47ae148p-1, 0x1.446f865p-1, 0x1.4141414p-1, 0x1.3e22cbdp-1,
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0x1.3b13b14p-1, 0x1.3813814p-1, 0x1.3521cfbp-1, 0x1.323e34ap-1,
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0x1.2f684bep-1, 0x1.2c9fb4ep-1, 0x1.29e412ap-1, 0x1.27350b9p-1,
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0x1.2492492p-1, 0x1.21fb781p-1, 0x1.1f7047ep-1, 0x1.1cf06aep-1,
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0x1.1a7b961p-1, 0x1.1811812p-1, 0x1.15b1e5fp-1, 0x1.135c811p-1,
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0x1.1111111p-1, 0x1.0ecf56cp-1, 0x1.0c9715p-1, 0x1.0a6810ap-1,
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0x1.0842108p-1, 0x1.0624dd3p-1, 0x1.041041p-1, 0x1.0204081p-1,
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0.5
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};
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static const double tl[] =
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{
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-0x1.d45fd6237ebe3p-47, 0x1.b947689311b6ep-8, 0x1.b5e909c96d7d5p-7,
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0x1.45f4f59ed2165p-6, 0x1.af5f92cbd8f1ep-6, 0x1.0ba01a606de8cp-5,
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0x1.3ed119b9a2b7bp-5, 0x1.714834298eec2p-5, 0x1.a30a9d98357fbp-5,
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0x1.d41d512670813p-5, 0x1.02428c0f65519p-4, 0x1.1a23444eecc3ep-4,
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0x1.31b30543f4cb4p-4, 0x1.48f3ed39bfd04p-4, 0x1.5fe8049a0e423p-4,
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0x1.769140a6aa008p-4, 0x1.8cf1836c98cb3p-4, 0x1.a30a9d55541a1p-4,
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0x1.b8de4d1ee823ep-4, 0x1.ce6e4202ca2e6p-4, 0x1.e3bc1accace07p-4,
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0x1.f8c9683b5abd4p-4, 0x1.06cbd68ca9a6ep-3, 0x1.11142f19df73p-3,
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0x1.1b3e71fa7a97fp-3, 0x1.254b4d37a46e3p-3, 0x1.2f3b6912cbf07p-3,
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0x1.390f683115886p-3, 0x1.42c7e7fffc5a8p-3, 0x1.4c65808c78d3cp-3,
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0x1.55e8c50751c55p-3, 0x1.5f52445dec3d8p-3, 0x1.68a288c3f12p-3,
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0x1.71da17bdf0d19p-3, 0x1.7af973608afd9p-3, 0x1.84011952a2579p-3,
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0x1.8cf1837a7ea6p-3, 0x1.95cb2891e43d6p-3, 0x1.9e8e7b0f869ep-3,
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0x1.a73beaa5db18dp-3, 0x1.afd3e394558d3p-3, 0x1.b856cf060d9f1p-3,
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0x1.c0c5134de1ffcp-3, 0x1.c91f1371bc99fp-3, 0x1.d1652ffcd3f53p-3,
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0x1.d997c6f635e75p-3, 0x1.e1b733ab90f3bp-3, 0x1.e9c3ceadac856p-3,
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0x1.f1bdeec43a305p-3, 0x1.f9a5e7a5fa3fep-3, 0x1.00be05ac02f2bp-2,
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0x1.04a054d81a2d4p-2, 0x1.087a0835957fbp-2, 0x1.0c4b457099517p-2,
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0x1.101431aa1fe51p-2, 0x1.13d4f08b98dd8p-2, 0x1.178da53edb892p-2,
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0x1.1b3e71e9f9d58p-2, 0x1.1ee777defdeedp-2, 0x1.2288d7b48e23bp-2,
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0x1.2622b0f52e49fp-2, 0x1.29b522a4c6314p-2, 0x1.2d404b0e30f8p-2,
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0x1.30c4478f3fbe5p-2, 0x1.34413509f7915p-2
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};
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static const union
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{
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float f;
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uint32_t u;
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} st[] =
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{
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{ 0x1p+0 }, { 0x1.4p+3 }, { 0x1.9p+6 }, { 0x1.f4p+9 },
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{ 0x1.388p+13 }, { 0x1.86ap+16 }, { 0x1.e848p+19 }, { 0x1.312dp+23 },
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{ 0x1.7d784p+26 }, { 0x1.dcd65p+29 }, { 0x1.2a05f2p+33 }, { 0 },
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{ 0 }, { 0 }, { 0 }, { 0 }
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};
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static const double b[] =
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{
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0x1.bcb7b15c5a2f8p-2, -0x1.bcbb1dbb88ebap-3, 0x1.2871c39d521c6p-3
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};
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static const double c[] =
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{
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0x1.bcb7b1526e50ep-2, -0x1.bcb7b1526e53dp-3, 0x1.287a7636f3fa2p-3,
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-0x1.bcb7b146a14b3p-4, 0x1.63c627d5219cbp-4, -0x1.2880736c8762dp-4,
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0x1.fc1ecf913961ap-5
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};
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uint32_t ux = asuint (x);
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if (__glibc_unlikely (ux < (1 << 23) || ux >= 0x7f800000u))
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{
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if (ux == 0 || ux >= 0x7f800000u)
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return as_special (x);
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/* subnormal */
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int n = __builtin_clz (ux) - 8;
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ux <<= n;
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ux -= n << 23;
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}
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unsigned m = ux & ((1 << 23) - 1), j = (m + (1 << (23 - 7))) >> (23 - 6);
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double ix = tr[j], l = tl[j];
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int e = ((int) ux >> 23) - 127;
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unsigned je = e + 1;
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je = (je * 0x4d104d4) >> 28;
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if (__glibc_unlikely (ux == st[je].u))
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return je;
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double tz = asdouble (((int64_t) m | ((int64_t) 1023 << 23)) << (52 - 23));
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double z = tz * ix - 1, z2 = z * z;
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double r
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= ((e * 0x1.34413509f79ffp-2 + l) + z * b[0]) + z2 * (b[1] + z * b[2]);
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float ub = r, lb = r + 0x1.b008p-34;
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if (__glibc_unlikely (ub != lb))
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{
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double f = z
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* ((c[0] + z * c[1])
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+ z2
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* ((c[2] + z * c[3])
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+ z2 * (c[4] + z * c[5] + z2 * c[6])));
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f -= 0x1.0cee0ed4ca7e9p-54 * e;
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f += l - tl[0];
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double el = e * 0x1.34413509f7ap-2;
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r = el + f;
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ub = r;
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tz = r;
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if (__glibc_unlikely (!((asuint64 (tz) & ((1 << 28) - 1)))))
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{
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double dr = (el - r) + f;
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r += dr * 32;
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ub = r;
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}
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}
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return ub;
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}
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libm_alias_finite (__ieee754_log10f, __log10f)
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