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-rw-r--r--src/lib/netlist/nl_util.h95
1 files changed, 95 insertions, 0 deletions
diff --git a/src/lib/netlist/nl_util.h b/src/lib/netlist/nl_util.h
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+++ b/src/lib/netlist/nl_util.h
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+// license:GPL-2.0+
+// copyright-holders:Couriersud
+/*
+ * nl_util.h
+ *
+ */
+
+#ifndef NL_UTIL_H_
+#define NL_UTIL_H_
+
+#include <cmath>
+#include <cstring>
+#include <cstdlib>
+
+#include "plib/pstring.h"
+#include "plib/plists.h"
+
+class nl_util
+{
+// this is purely static
+private:
+ nl_util() {};
+
+public:
+
+
+ static const pstring environment(const pstring &var, const pstring &default_val = "")
+ {
+ if (getenv(var.cstr()) == NULL)
+ return default_val;
+ else
+ return pstring(getenv(var.cstr()));
+ }
+};
+
+class nl_math
+{
+// this is purely static
+private:
+ nl_math() {};
+
+public:
+ ATTR_HOT inline static float exp(const float x) { return std::exp(x); }
+ ATTR_HOT inline static double abs(const double x) { return std::abs(x); }
+ ATTR_HOT inline static float abs(const float x) { return std::abs(x); }
+ ATTR_HOT inline static double log(const double x) { return std::log(x); }
+ ATTR_HOT inline static float log(const float x) { return std::log(x); }
+#if defined(_MSC_VER) && _MSC_VER < 1800
+ ATTR_HOT inline static double e_log1p(const double x) { return nl_math::log(1.0 + x); }
+ ATTR_HOT inline static float e_log1p(const float x) { return nl_math::log(1.0 + x); }
+#else
+ ATTR_HOT inline static double e_log1p(const double x) { return log1p(x); }
+ ATTR_HOT inline static float e_log1p(const float x) { return log1pf(x); }
+#endif
+ ATTR_HOT inline static double sqrt(const double x) { return std::sqrt(x); }
+ ATTR_HOT inline static float sqrt(const float x) { return std::sqrt(x); }
+
+ // this one has an accuracy of better than 5%. That's enough for our purpose
+ // add c3 and it'll be better than 1%
+
+#if 0
+ inline static double fastexp_h(const double x)
+ {
+ /* static */ const double ln2r = 1.442695040888963387;
+ /* static */ const double ln2 = 0.693147180559945286;
+ /* static */ const double c3 = 0.166666666666666667;
+ /* static */ const double c4 = 1.0 / 24.0;
+ /* static */ const double c5 = 1.0 / 120.0;
+
+ const double y = x * ln2r;
+ const UINT32 t = y;
+ const double z = (x - ln2 * (double) t);
+ const double e = (1.0 + z * (1.0 + z * (0.5 + z * (c3 + z * (c4 + c5*z)))));
+
+ if (t < 63)
+ //return (double)((UINT64) 1 << t)*(1.0 + z + 0.5 * zz + c3 * zzz+c4*zzzz+c5*zzzzz);
+ return (double)((UINT64) 1 << t) * e;
+ else
+ return pow(2.0, t)*e;
+ }
+
+ ATTR_HOT inline static double exp(const double x)
+ {
+ if (x<0)
+ return 1.0 / fastexp_h(-x);
+ else
+ return fastexp_h(x);
+ }
+#else
+ ATTR_HOT inline static double exp(const double x) { return std::exp(x); }
+#endif
+
+};
+
+#endif /* NL_UTIL_H_ */