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README.md

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+# utask
+
+utask (micro-task) is an extremely lightweight cooperative multitasking
+library. µTasks are simply executed round-robin until each one yields.
+
+By using compiler extensions in the form of synchronization builtins and
+carefully constructed clobber lists, utask gets an absolutely minimal context
+switch. Instead of saving and restoring all registers every time (on some
+architectures this is a lot — a RISC-V with floating point has 63 registers!),
+utask simply invalidates all registers before the context switch. This tells
+the compiler that after the switch, it is responsible for recomputing the
+contents of any registers that had active allocations. This is _much_ faster,
+because chances are, you do not have all 63 registers in use at once.
+
+## Supported architectures
+
+- RISC-V
+
+## API example
+
+```c
+static void task1_f(uintptr_t arg);
+static void task2_f(uintptr_t arg);
+
+utask_decl_stack(task1_s, 1024);
+utask_decl_stack(task2_s, 1024);
+
+utask_t task1 = {
+	.func = task1_f,
+	.stack = task1_s,
+	.stack_size = sizeof(task1_s),
+	.name = "task1",
+	UTASK_INIT
+};
+
+utask_t task2 = {
+	.func = task2_f,
+	.stack = task2_s,
+	.stack_size = sizeof(task2_s),
+	.name = "task2",
+	UTASK_INIT
+};
+
+int main()
+{
+	utask_add(&task2, 0);
+	utask_add(&task1, 0);
+	utask_run();
+}
+
+static void task1_f(uintptr_t arg)
+{
+	printf("Hello, ");
+	utask_yield();
+}
+
+static void task2_f(uintptr_t arg)
+{
+	printf("world!\n");
+	utask_yield();
+}
+```
+
+## Copying
+
+This code may not be used by anybody for any purpose. Be gay, do crime.