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b2e3e3e30e
This is a full re-write of the CMake Tutorial for CMake 3.23, both the functionality it provides, as well as the modern workflows that developers use when interfacing with CMake. Issue: #22663, #23086, #23799, #26053, #26105, #26153, #26914
80 lines
1.6 KiB
C++
80 lines
1.6 KiB
C++
#include <cmath>
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#include <format>
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#include <MathLogger.h>
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// TODO3: If the TUTORIAL_USE_SSE2 definition is set, include
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// the <emmintrin.h> header
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namespace {
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mathlogger::Logger Logger;
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#if defined(TUTORIAL_USE_GNU_BUILTIN)
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typedef double v2df __attribute__((vector_size(16)));
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double gnu_mysqrt(double x)
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{
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v2df root = __builtin_ia32_sqrtsd(v2df{ x, 0.0 });
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double result = root[0];
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Logger.Log(std::format("Computed sqrt of {} to be {} with GNU-builtins\n", x,
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result));
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return result;
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}
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#elif defined(TUTORIAL_USE_SSE2)
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double sse2_mysqrt(double x)
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{
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__m128d root = _mm_sqrt_sd(_mm_setzero_pd(), _mm_set_sd(x));
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double result = _mm_cvtsd_f64(root);
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Logger.Log(
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std::format("Computed sqrt of {} to be {} with SSE2\n", x, result));
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return result;
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}
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#endif
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// a hack square root calculation using simple operations
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double fallback_mysqrt(double x)
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{
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if (x <= 0) {
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return 0;
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}
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double result = x;
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// do ten iterations
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for (int i = 0; i < 10; ++i) {
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if (result <= 0) {
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result = 0.1;
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}
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double delta = x - (result * result);
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result = result + 0.5 * delta / result;
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Logger.Log(std::format("Computing sqrt of {} to be {}\n", x, result));
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}
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return result;
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}
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double mysqrt(double x)
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{
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#if defined(TUTORIAL_USE_GNU_BUILTIN)
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return gnu_mysqrt(x);
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#elif defined(TUTORIAL_USE_SSE2)
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return sse2_mysqrt(x);
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#else
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return fallback_mysqrt(x);
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#endif
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}
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}
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namespace mathfunctions {
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double sqrt(double x)
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{
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#ifdef TUTORIAL_USE_STD_SQRT
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return std::sqrt(x);
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#else
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return mysqrt(x);
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#endif
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}
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}
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