From dafaba7407d1d82d82be38ec2c47da9dea357132 Mon Sep 17 00:00:00 2001
From: Mathieu Maret <mathieu.maret@gmail.com>
Date: Fri, 24 Apr 2020 23:34:34 +0200
Subject: [PATCH] kthread implement yield

---
 core/kthread.c | 36 +++++++++++++++++++++++++++++-------
 core/kthread.h |  7 +++----
 tests/test.c   | 28 ++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 11 deletions(-)

diff --git a/core/kthread.c b/core/kthread.c
index 69fb4c7..fce5417 100644
--- a/core/kthread.c
+++ b/core/kthread.c
@@ -1,19 +1,25 @@
-#include "assert.h"
 #include "kthread.h"
-#include "list.h"
 #include "alloc.h"
+#include "assert.h"
+#include "irq.h"
 #include "klibc.h"
+#include "list.h"
 #include "vga.h"
 
 static struct kthread *currentThread;
 
-void kthreadExit(){
+void kthreadExit()
+{
+        uint32_t flags;
+        disable_IRQs(flags);
         struct kthread *current = currentThread;
-        struct kthread *next =  kthreadSelectNext();
+        struct kthread *next    = kthreadSelectNext();
         if (next == current)
                 assert("cannot exit thread");
         currentThread = next;
-        cpu_context_exit_to(next->cpuState, (cpu_kstate_function_arg1_t *)kthreadDelete, (uint32_t)current);
+        cpu_context_exit_to(next->cpuState, (cpu_kstate_function_arg1_t *)kthreadDelete,
+                            (uint32_t)current);
+        restore_IRQs(flags);
         return;
 }
 
@@ -71,10 +77,26 @@ struct kthread *kthreadSelectNext(){
         return nextThread;
 }
 
-struct cpu_state *switchKthread(struct cpu_state *prevCpu){
-        currentThread->cpuState = prevCpu;
+struct cpu_state *switchKthread(struct cpu_state *prevCpu)
+{
+        uint32_t flags;
+        disable_IRQs(flags);
+        currentThread->cpuState    = prevCpu;
         struct kthread *nextThread = kthreadSelectNext();
         printStringDetails(nextThread->name, RED, BLACK, 40, VGA_HEIGHT - 1);
         currentThread = nextThread;
+        restore_IRQs(flags);
         return nextThread->cpuState;
 }
+
+int kthreadYield()
+{
+        uint32_t flags;
+        disable_IRQs(flags);
+        struct kthread *next    = kthreadSelectNext();
+        struct kthread *current = currentThread;
+        currentThread           = next;
+        cpu_context_switch(&current->cpuState, next->cpuState);
+        restore_IRQs(flags);
+        return 0;
+}
diff --git a/core/kthread.h b/core/kthread.h
index 60183f7..128bb8f 100644
--- a/core/kthread.h
+++ b/core/kthread.h
@@ -15,14 +15,13 @@ struct kthread {
 	struct kthread *prev;
 };
 
-
 int kthreadSetup(vaddr_t mainStack, size_t mainStackSize);
 void kthreadExit();
 
-struct kthread *kthreadCreate(const char *name, cpu_kstate_function_arg1_t func,
-			      void *args);
-
+struct kthread *kthreadCreate(const char *name, cpu_kstate_function_arg1_t func, void *args);
 void kthreadDelete(struct kthread *thread);
 
 struct kthread *kthreadSelectNext();
 struct cpu_state *switchKthread(struct cpu_state *prevCpu);
+
+int kthreadYield();
diff --git a/tests/test.c b/tests/test.c
index 17ffc57..c970349 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -2,6 +2,7 @@
 #include "assert.h"
 #include "cpu_context.h"
 #include "klibc.h"
+#include "kthread.h"
 #include "list.h"
 #include "mem.h"
 #include "paging.h"
@@ -217,6 +218,32 @@ void testCoroutine()
     printf("Back in main !\n");
 }
 
+static void kthread1(void *strIn)
+{
+    char *str = (char *)strIn;
+    printf("\nkth1: %s\n", (char *)strIn);
+    for (; *str != '\n'; str++) {
+        printf("kth1_: %c\n", *str);
+	kthreadYield();
+    }
+}
+
+static void kthread2(void *strIn)
+{
+    char *str = (char *)strIn;
+    printf("\nkth2: %s\n", (char *)strIn);
+    for (; *str != '\n'; str++) {
+        printf("kth2_: %c\n", *str);
+	kthreadYield();
+    }
+}
+
+void testKthread()
+{
+	kthreadCreate("Test1", (cpu_kstate_function_arg1_t *)kthread1, (void *)"Hlowrd\n");
+	kthreadCreate("Test2", (cpu_kstate_function_arg1_t *)kthread2, (void *)"el ol\n");
+}
+
 void run_test(void)
 {
 	testPaging();
@@ -230,4 +257,5 @@ void run_test(void)
 	printf("Testing backtrace\n");
 	test_backtrace();
 	testCoroutine();
+	testKthread();
 }