[fiber] Add stack size query to context and task

Author: salkinium

src/modm/processing/fiber/context.h

@@ -97,6 +97,12 @@ modm_context_stack_watermark(modm_context_t *ctx);
  */
 size_t
 modm_context_stack_usage(const modm_context_t *ctx);
+
+/**
+ * Returns the configured stack size.
+ */
+size_t
+modm_context_stack_size(const modm_context_t *ctx);
 /// @}
 
 #ifdef __cplusplus

src/modm/processing/fiber/context_arm64.cpp

@@ -113,6 +113,12 @@ modm_context_stack_usage(const modm_context_t *ctx)
 	return 0;
 }
 
+size_t
+modm_context_stack_size(const modm_context_t *ctx)
+{
+	return (ctx->top - ctx->bottom) * StackSizeWord;
+}
+
 static modm_context_t main_context;
 
 uintptr_t

src/modm/processing/fiber/context_arm_m.cpp.in

@@ -139,6 +139,12 @@ modm_context_stack_usage(const modm_context_t *ctx)
 	return 0;
 }
 
+size_t
+modm_context_stack_size(const modm_context_t *ctx)
+{
+	return (ctx->top - ctx->bottom) * StackSizeWord;
+}
+
 #define MODM_PUSH_CONTEXT() \
 %% if is_cm0
 		"push {r4-r7, lr}	\n\t" \

src/modm/processing/fiber/context_avr.cpp

@@ -146,6 +146,12 @@ modm_context_stack_usage(const modm_context_t *ctx)
 	return 0;
 }
 
+size_t
+modm_context_stack_size(const modm_context_t *ctx)
+{
+	return (ctx->top - ctx->bottom) * StackSizeWord;
+}
+
 extern "C" uintptr_t modm_context_jump_entry(modm_context_t*, modm_context_t*);
 extern "C" void modm_context_jump_return(uintptr_t, modm_context_t*);
 static uintptr_t main_context_sp;

src/modm/processing/fiber/context_x86_64.cpp.in

@@ -120,6 +120,12 @@ modm_context_stack_usage(const modm_context_t *ctx)
 	return 0;
 }
 
+size_t
+modm_context_stack_size(const modm_context_t *ctx)
+{
+	return (ctx->top - ctx->bottom) * StackSizeWord;
+}
+
 static modm_context_t main_context;
 
 uintptr_t

src/modm/processing/fiber/module.md

@@ -289,7 +289,8 @@ fiber1.stack_watermark();
 // now you can run the fibers via the scheduler
 modm::fiber::Scheduler::run();
 // can be called from inside or outside the fiber, before or after running!
-size_t bytes = fiber.stack_usage();
+size_t total = fiber.stack_size();
+size_t used = fiber.stack_usage();
 ```
 
 Note that stack usage measurement through watermarking can be inaccurate if the

src/modm/processing/fiber/task.hpp

@@ -142,6 +142,14 @@ class Task
 		return modm_context_stack_usage(&ctx);
 	}
 
+	/// @returns the available stack size excluding the storage of the callable.
+	/// @see `modm_context_stack_size()`.
+	[[nodiscard]] size_t inline
+	stack_size() const
+	{
+		return modm_context_stack_size(&ctx);
+	}
+
 	/// Adds the task to the currently active scheduler, if not already running.
 	/// @returns if the fiber has been scheduled.
 	bool