base, python: Add a Temperature type and associated param

Add a class to represent a temperature. The class stores temperatures
in Kelvin and provides helper methods to convert to/from Celsius. The
corresponding param type automatically converts from Kelvin, Celsius,
and Fahrenheit to the underlying C++ type.

Change-Id: I5783cc4f4fecbea5aba9821dfc71bfa77c3f75a9
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39218
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/python/m5/params.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2012-2014, 2017-2019 ARM Limited
+# Copyright (c) 2012-2014, 2017-2019, 2021 Arm Limited
 # All rights reserved.
 #
 # The license below extends only to copyright in the software and shall
@@ -1693,6 +1693,43 @@ class Energy(Float):
         value = convert.toEnergy(value)
         super(Energy, self).__init__(value)
 
+class Temperature(ParamValue):
+    cxx_type = 'Temperature'
+    cmd_line_settable = True
+    ex_str = "1C"
+
+    def __init__(self, value):
+        self.value = convert.toTemperature(value)
+
+    def __call__(self, value):
+        self.__init__(value)
+        return value
+
+    def getValue(self):
+        from _m5.core import Temperature
+        return Temperature.fromKelvin(self.value)
+
+    def config_value(self):
+        return self
+
+    @classmethod
+    def cxx_predecls(cls, code):
+        code('#include "base/temperature.hh"')
+
+    @classmethod
+    def cxx_ini_predecls(cls, code):
+        # Assume that base/str.hh will be included anyway
+        # code('#include "base/str.hh"')
+        pass
+
+    @classmethod
+    def cxx_ini_parse(self, code, src, dest, ret):
+        code('double _temp;')
+        code('bool _ret = to_number(%s, _temp);' % src)
+        code('if (_ret)')
+        code('    %s = Temperature(_temp);' % dest)
+        code('%s _ret;' % ret)
+
 class NetworkBandwidth(float,ParamValue):
     cxx_type = 'float'
     ex_str = "1Gbps"
@@ -2231,6 +2268,7 @@ __all__ = ['Param', 'VectorParam',
            'IpAddress', 'IpNetmask', 'IpWithPort',
            'MemorySize', 'MemorySize32',
            'Latency', 'Frequency', 'Clock', 'Voltage', 'Current', 'Energy',
+           'Temperature',
            'NetworkBandwidth', 'MemoryBandwidth',
            'AddrRange',
            'MaxAddr', 'MaxTick', 'AllMemory',

src/python/m5/util/convert.py

@@ -292,3 +292,25 @@ def toCurrent(value):
 
 def toEnergy(value):
     return toMetricFloat(value, 'energy', 'J')
+
+def toTemperature(value):
+    """Convert a string value specified to a temperature in Kelvin"""
+
+    magnitude, unit = toNum(value,
+                            target_type='temperature',
+                            units=('K', 'C', 'F'),
+                            prefixes=metric_prefixes,
+                            converter=float)
+    if unit == 'K':
+        kelvin = magnitude
+    elif unit == 'C':
+        kelvin = magnitude + 273.15
+    elif unit == 'F':
+        kelvin = (magnitude + 459.67) / 1.8
+    else:
+        raise ValueError(f"'{value}' needs a valid temperature unit.")
+
+    if kelvin < 0:
+        raise ValueError(f"{value} is an invalid temperature")
+
+    return kelvin

src/python/pybind11/core.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2019 ARM Limited
+ * Copyright (c) 2017, 2019, 2021 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -52,6 +52,7 @@
 #include "base/logging.hh"
 #include "base/random.hh"
 #include "base/socket.hh"
+#include "base/temperature.hh"
 #include "base/types.hh"
 #include "sim/core.hh"
 #include "sim/drain.hh"
@@ -220,6 +221,38 @@ pybind_init_core(py::module &m_native)
         .def("__sub__", &Cycles::operator-)
         ;
 
+    py::class_<Temperature>(m_core, "Temperature")
+        .def(py::init<>())
+        .def(py::init<double>())
+        .def_static("from_celsius", &Temperature::fromCelsius)
+        .def_static("from_kelvin", &Temperature::fromKelvin)
+        .def_static("from_fahrenheit", &Temperature::fromFahrenheit)
+        .def("celsius", &Temperature::toCelsius)
+        .def("kelvin", &Temperature::toKelvin)
+        .def("fahrenheit", &Temperature::toFahrenheit)
+        .def(py::self == py::self)
+        .def(py::self != py::self)
+        .def(py::self < py::self)
+        .def(py::self <= py::self)
+        .def(py::self > py::self)
+        .def(py::self >= py::self)
+        .def(py::self + py::self)
+        .def(py::self - py::self)
+        .def(py::self * float())
+        .def(float() * py::self)
+        .def(py::self / float())
+        .def("__str__", [](const Temperature &t) {
+                std::stringstream s;
+                s << t;
+                return s.str();
+            })
+        .def("__repr__", [](const Temperature &t) {
+                std::stringstream s;
+                s << "Temperature(" << t.toKelvin() << ")";
+                return s.str();
+            })
+        ;
+
     py::class_<tm>(m_core, "tm")
         .def_static("gmtime", [](std::time_t t) { return *std::gmtime(&t); })
         .def_readwrite("tm_sec", &tm::tm_sec)