updated stuff to use an array for now

src/PCB.c

@@ -2,27 +2,43 @@
 #include "serial.h"
 #include "term.h"
 #define NUM_SYSCALLS 256
+#define NUM_PROCS 16
 
-process* curproc;
-process* otherproc;
+process* procs[NUM_PROCS]; 
+int curproc=-1;
+int firstfree=0;
 
-void setproc(process* proc)
+//process* curproc;
+//process* otherproc;
+
+void addproc(process* proc)
 {
-    curproc=proc; 
+    procs[firstfree]=proc;
+    firstfree++;
+    //curproc=proc; 
 }
 
 void schedule()
 {
-    context_switch(&curproc->ctxt, otherproc->ctxt);
-    process* t = curproc;
-    curproc = otherproc;
-    otherproc = t;
+    int old = curproc;
+    curproc++;
+    while(procs[curproc]==0 || procs[curproc]->state!=RUNNABLE)
+    {
+        curproc=(curproc<NUM_PROCS-1)?curproc+1:0;
+    }
+    context_switch(&procs[old]->ctxt, procs[curproc]->ctxt);
+    //procs[old]->state=RUNNABLE;
+    procs[curproc]->state=RUNNING;
+    //process* t = curproc;
+    //curproc = otherproc;
+    //otherproc = t;
+    
 }
 
 int yield()
 {
     //lock mutex
-    curproc->state = RUNNABLE;
+    procs[curproc]->state = RUNNABLE;
     schedule();
     //unlock mutex
     return 1;
@@ -45,15 +61,23 @@ int(*syscalls[NUM_SYSCALLS])()={0,0,0, yield, print1, print2};
 
 void syscall()
 {
-    int num = curproc->tf->eax;
+    int num = procs[curproc]->tf->eax;
     
     if(num>0 && num<NUM_SYSCALLS && syscalls[num])
     {
-        curproc->tf->eax = syscalls[num]();
+        procs[curproc]->tf->eax = syscalls[num]();
     }
     else
     {
         serial_writestring("UNKNOWN SYSCALL CALLED\n");
-        curproc->tf->eax = -1;
+        procs[curproc]->tf->eax = -1;
+    }
+}
+
+void proc_setup()
+{
+    for(int i=0;i<NUM_PROCS;i++)
+    {
+        procs[i]=NULL;
     }
 }

src/PCB.h

@@ -65,6 +65,7 @@ typedef struct
 
 extern void context_switch(context** old, context* new);
 void syscall();
-void setproc(process* proc);
+void addproc(process* proc);
+void proc_setup();
 
 #endif

src/kern.c

@@ -20,6 +20,7 @@
 #include "pit.h"
 #include "io.h"
 #include "elf.h"
+#include "PCB.h"
 
 // The parameters passed here ultimately come through the bootloader
 void kernel_main(multiboot_info* mbt, uint32_t magic)
@@ -39,6 +40,7 @@ void kernel_main(multiboot_info* mbt, uint32_t magic)
     pic_init(0x20,0x28);
     pit_init();
     io_init();
+    proc_setup();
     pit_start_counter(100, PIT_OCW_CONT_0, PIT_OCW_MODE_SQWVGEN);
     enable_int();