feat:Cooperative Multitasking

2 files changed, 147 insertions, 0 deletions

diff --git a/src/kernel/proc/proc.cc b/src/kernel/proc/proc.cc
new file mode 100644
index 0000000..469b7eb
--- /dev/null
+++ b/src/kernel/proc/proc.cc
@@ -0,0 +1,113 @@
+#include "kernel/proc.h"
+#include "kernel/pmm.h"
+#include "drivers/uart.h"
+
+#define NPROC 10
+
+void str_copy(char *dst, const char *src)
+{
+    while (*src)
+        *dst++ = *src++;
+    *dst = 0;
+}
+
+extern "C" void swtch(struct Context *old_ctx, struct Context *new_ctx);
+
+struct Proc procs[NPROC];
+struct Context main_context;
+
+namespace ProcManager
+{
+    void init()
+    {
+        for (int i = 0; i < NPROC; i++)
+        {
+            procs[i].state = UNUSED;
+        }
+    }
+
+    void create_kernel_thread(void (*func)(), const char *name)
+    {
+        struct Proc *p = nullptr;
+        for(int i = 0; i < NPROC; i++)
+        {
+            if(procs[i].state == UNUSED)
+            {
+                p = &procs[i];
+                p->pid = i + 1;
+                break;
+            }
+        }
+
+        if (!p)
+        {
+            Drivers::uart_puts("Error: No free process slots!\n");
+            return;
+        }
+
+        p->kstack = PMM::alloc_page();
+        if (!p->kstack)
+        {
+            Drivers::uart_puts("Error: Alloc kstack failed!\n");
+            return;
+        }
+
+        p->context.ra = (uint64)func;
+
+        p->context.sp = (uint64)p->kstack + 4096;
+
+        p->state = RUNNABLE;
+        str_copy(p->name, name);
+
+        Drivers::uart_puts("[Proc] Created thread: ");
+        Drivers::uart_puts(name);
+        Drivers::uart_puts("\n");
+    }
+
+    void yield()
+    {
+        struct Proc *p = nullptr;
+        for(int i = 0; i < NPROC; i++)
+        {
+            if (procs[i].state == RUNNING)
+            {
+                p = &procs[i];
+                break;
+            }
+        }
+        if(p)
+        {
+            p->state = RUNNABLE;
+            swtch(&p->context, &main_context);
+        }
+    }
+
+    void scheduler()
+    {
+        struct Proc *p = nullptr;
+        Drivers::uart_puts("[Proc] Scheduler started.\n");
+
+        for (;;)
+        {
+            // int nothing_to_run = 1;
+
+            intr_off();
+
+            for (p = procs; p < &procs[NPROC]; p++)
+            {
+                if (p->state == RUNNABLE)
+                {
+                    // nothing_to_run = 0;
+
+                    p->state = RUNNING;
+
+                    intr_on();
+
+                    swtch(&main_context, &p->context);
+
+                    intr_off();
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/kernel/proc/swtch.S b/src/kernel/proc/swtch.S
new file mode 100644
index 0000000..f59de20
--- /dev/null
+++ b/src/kernel/proc/swtch.S
@@ -0,0 +1,34 @@
+.global swtch
+
+swtch:
+    sd ra, 0(a0)
+    sd sp, 8(a0)
+    sd s0, 16(a0)
+    sd s1, 24(a0)
+    sd s2, 32(a0)
+    sd s3, 40(a0)
+    sd s4, 48(a0)
+    sd s5, 56(a0)
+    sd s6, 64(a0)
+    sd s7, 72(a0)
+    sd s8, 80(a0)
+    sd s9, 88(a0)
+    sd s10, 96(a0)
+    sd s11, 104(a0)
+
+    ld ra, 0(a1)
+    ld sp, 8(a1)
+    ld s0, 16(a1)
+    ld s1, 24(a1)
+    ld s2, 32(a1)
+    ld s3, 40(a1)
+    ld s4, 48(a1)
+    ld s5, 56(a1)
+    ld s6, 64(a1)
+    ld s7, 72(a1)
+    ld s8, 80(a1)
+    ld s9, 88(a1)
+    ld s10, 96(a1)
+    ld s11, 104(a1)
+
+    ret