Fixed error in green threads example. See: https://github.com/cfsamson/example-greenthreads/issues/20. Ugh... But it works now!

src/0_background_information.md

@@ -149,6 +149,7 @@ _**Press the expand icon in the top right corner to show the example code.**_
 
 ```rust, edition2018
 # #![feature(llvm_asm, naked_functions)]
+# use std::ptr;
 #
 # const DEFAULT_STACK_SIZE: usize = 1024 * 1024 * 2;
 # const MAX_THREADS: usize = 4;
@@ -171,6 +172,7 @@ _**Press the expand icon in the top right corner to show the example code.**_
 #     stack: Vec<u8>,
 #     ctx: ThreadContext,
 #     state: State,
+#     task: Option<Box<dyn Fn()>>,
 # }
 #
 # #[derive(Debug, Default)]
@@ -183,6 +185,7 @@ _**Press the expand icon in the top right corner to show the example code.**_
 #     r12: u64,
 #     rbx: u64,
 #     rbp: u64,
+#     thread_ptr: u64,
 # }
 #
 # impl Thread {
@@ -192,6 +195,7 @@ _**Press the expand icon in the top right corner to show the example code.**_
 #             stack: vec![0_u8; DEFAULT_STACK_SIZE],
 #             ctx: ThreadContext::default(),
 #             state: State::Available,
+#             task: None,
 #         }
 #     }
 # }
@@ -203,9 +207,11 @@ _**Press the expand icon in the top right corner to show the example code.**_
 #             stack: vec![0_u8; DEFAULT_STACK_SIZE],
 #             ctx: ThreadContext::default(),
 #             state: State::Running,
+#             task: None,
 #         };
 #
 #         let mut threads = vec![base_thread];
+#         threads[0].ctx.thread_ptr = &threads[0] as *const Thread as u64;
 #         let mut available_threads: Vec<Thread> = (1..MAX_THREADS).map(|i| Thread::new(i)).collect();
 #         threads.append(&mut available_threads);
 #
@@ -263,28 +269,39 @@ _**Press the expand icon in the top right corner to show the example code.**_
 #            );
 #            switch();
 #        }
-#         self.threads.len() > 0
+#         true
 #     }
 #
-#     pub fn spawn(&mut self, f: fn()) {
+#     pub fn spawn<F: Fn() + 'static>(f: F){
-#         let available = self
+#         unsafe {
+#             let rt_ptr = RUNTIME as *mut Runtime;
+#             let available = (*rt_ptr)
 #                 .threads
 #                 .iter_mut()
 #                 .find(|t| t.state == State::Available)
 #                 .expect("no available thread.");
 #
 #             let size = available.stack.len();
-#         unsafe {
 #             let s_ptr = available.stack.as_mut_ptr().offset(size as isize);
 #             let s_ptr = (s_ptr as usize & !15) as *mut u8;
+#             available.task = Some(Box::new(f));
+#             available.ctx.thread_ptr = available as *const Thread as u64;
+#             //ptr::write(s_ptr.offset((size - 8) as isize) as *mut u64, guard as u64);
 #             std::ptr::write(s_ptr.offset(-16) as *mut u64, guard as u64);
 #             std::ptr::write(s_ptr.offset(-24) as *mut u64, skip as u64);
-#             std::ptr::write(s_ptr.offset(-32) as *mut u64, f as u64);
+#             std::ptr::write(s_ptr.offset(-32) as *mut u64, call as u64);
 #             available.ctx.rsp = s_ptr.offset(-32) as u64;
-#         }
 #             available.state = State::Ready;
 #         }
 #     }
+# }
+#
+# fn call(thread: u64) {
+#     let thread = unsafe { &*(thread as *const Thread) };
+#     if let Some(f) = &thread.task {
+#         f();
+#     }
+# }
 #
 # #[naked]
 # fn skip() { }
@@ -292,7 +309,9 @@ _**Press the expand icon in the top right corner to show the example code.**_
 # fn guard() {
 #     unsafe {
 #         let rt_ptr = RUNTIME as *mut Runtime;
-#         (*rt_ptr).t_return();
+#         let rt = &mut *rt_ptr;
+#         println!("THREAD {} FINISHED.", rt.threads[rt.current].id);
+#         rt.t_return();
 #     };
 # }
 #
@@ -322,6 +341,7 @@ _**Press the expand icon in the top right corner to show the example code.**_
 #        mov     0x20(%rsi), %r12
 #        mov     0x28(%rsi), %rbx
 #        mov     0x30(%rsi), %rbp
+#        mov     0x38(%rsi), %rdi
 #        "
 #    );
 # }