[fiber] Implement resumable functions as fibers

Add experimental option for implementing resumable functions in terms of
fibers.

src/modm/processing/resumable/fiber/macros.hpp

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2021, Christopher Durand
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_RF_MACROS_HPP
+#define MODM_RF_MACROS_HPP
+
+#include <modm/architecture/interface/assert.hpp>
+#include <modm/architecture/utils.hpp>
+#include <modm/processing/fiber/scheduler.hpp>
+
+/// @ingroup modm_processing_resumable
+/// @{
+
+#define RF_BEGIN(index)
+
+#define RF_BEGIN()
+
+#define RF_END_RETURN(...) return __VA_ARGS__
+
+#define RF_END()
+
+#define RF_END_RETURN(...) return __VA_ARGS__
+
+#define RF_YIELD() modm::fiber::yield()
+
+#define RF_WAIT_WHILE(...) \
+    do { \
+        while (__VA_ARGS__) { \
+            modm::fiber::yield(); \
+        } \
+    } while(0)
+
+#define RF_WAIT_UNTIL(...) \
+    RF_WAIT_WHILE(!(__VA_ARGS__))
+
+#define RF_CALL(...) __VA_ARGS__
+
+// TODO: implement blocking
+#define RF_CALL(...) __VA_ARGS__
+
+#define RF_RETURN_CALL(...) return __VA_ARGS__
+
+#define RF_RETURN(...) return __VA_ARGS__
+
+#define RF_RETURN() return
+
+/// @}
+
+#endif
+
+#endif // MODM_RF_MACROS_HPP

src/modm/processing/resumable/fiber/nested_resumable.hpp

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2021, Christopher Durand
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_NESTED_RESUMABLE_HPP
+#define MODM_NESTED_RESUMABLE_HPP
+
+#include "macros.hpp"
+#include <cstdint>
+
+namespace modm
+{
+
+/**
+ * Dummy implementation to be used with fibers
+ *
+ * @ingroup	modm_processing_resumable
+ */
+template<uint8_t Levels = 1>
+class NestedResumable
+{};
+/// @endcond
+
+} // namespace modm
+
+#endif // MODM_NESTED_RESUMABLE_HPP

src/modm/processing/resumable/fiber/resumable.hpp

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2021, Christopher Durand
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_RESUMABLE_HPP
+#define MODM_RESUMABLE_HPP
+
+#include "macros.hpp"
+#include <cstdint>
+
+namespace modm
+{
+
+/**
+ * Dummy implementation to be used with fibers
+ *
+ * @ingroup	modm_processing_resumable
+ */
+template <typename T>
+using ResumableResult = T;
+
+/**
+ * Dummy implementation to be used with fibers
+ *
+ * @ingroup	modm_processing_resumable
+ */
+template<uint8_t Functions = 1>
+class Resumable
+{};
+
+} // namespace modm
+
+#endif // MODM_RESUMABLE_HPP

src/modm/processing/resumable/module.lb

@@ -19,19 +19,32 @@ def init(module):
 def prepare(module, options):
     module.depends(":architecture:assert")
 
-    module.add_option(
-        BooleanOption(
-            name="check_nesting_depth",
-            default=True,
-            description=descr_nesting_depth))
+    if not options[":processing:resumable:__use_fibers"]:
+        module.add_option(
+            BooleanOption(
+                name="check_nesting_depth",
+                default=True,
+                description=descr_nesting_depth))
+
+    if options[":__fibers"]:
+        module.add_option(
+            BooleanOption(
+                name="__use_fibers",
+                default=False,
+                description="Implement resumable functions with fibers for compatibility with drivers"))
 
     return True
 
 def build(env):
     env.outbasepath = "modm/src/modm/processing/resumable"
-    env.copy(".", ignore=env.ignore_files("*.md", "*.in"))
+    if env.get(":processing:resumable:__use_fibers", False):
+        env.copy("fiber/nested_resumable.hpp", "nested_resumable.hpp")
+        env.copy("fiber/resumable.hpp", "resumable.hpp")
+        env.copy("fiber/macros.hpp", "macros.hpp")
+    else:
+        env.copy(".", ignore=env.ignore_files("*.md", "*.in"))
+        env.template("nested_resumable.hpp.in")
     env.copy("../resumable.hpp")
-    env.template("nested_resumable.hpp.in")
 
 
 # ============================ Option Descriptions ============================