kopia lustrzana https://github.com/micropython/micropython
70 wiersze
2.6 KiB
C
70 wiersze
2.6 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2023 Damien P. George
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*
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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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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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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
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* THE SOFTWARE.
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*/
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#include <math.h>
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#include <stdint.h>
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#define INF_POS (0x7f800000)
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#define INF_NEG (0xff800000)
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union float_int_t {
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float f;
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uint32_t i;
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};
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float __wrap___aeabi_fadd(float x, float y);
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// The pico-sdk wraps __aeabi_fadd() with __wrap___aeabi_fadd() in order to use the ROM
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// floating-point functions. But __wrap___aeabi_fadd() does not handle inf+(-inf) or
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// (-inf)+inf correctly. To fix this we provide our own __aeabi_fadd() that fixes the
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// inf calculation, and do not use the "--wrap=" linker command. The compiler then
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// picks our __aeabi_fadd() instead of its built-in one. And the pico-sdk function
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// still exists for us to call.
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float __aeabi_fadd(float x, float y) {
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// Handle addition of inf/-inf. This is optimised to reduce C stack usage, and
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// only have one comparison/jump in the common case of x != inf.
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union float_int_t xu = {.f = x};
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union float_int_t yu = {.f = y};
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if ((xu.i << 1) == (INF_POS << 1)) {
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if (xu.i == INF_POS) {
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if (yu.i == INF_POS) {
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return INFINITY;
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} else if (yu.i == INF_NEG) {
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return NAN;
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}
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} else {
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if (yu.i == INF_POS) {
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return NAN;
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} else if (yu.i == INF_NEG) {
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return -INFINITY;
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}
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}
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}
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// Use the pico-sdk function for all other calculations.
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return __wrap___aeabi_fadd(x, y);
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}
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