horrible hacks and other stuff

src/PCB.c

 #include "PCB.h"
 #include "PCB.h"
+#include "serial.h"
+#include "term.h"
+#define NUM_SYSCALLS 256
+
+process* curproc;
+process* otherproc;
+
+void setproc(process* proc)
+{
+    curproc=proc; 
+}
+
+void schedule()
+{
+    context_switch(&curproc->ctxt, otherproc->ctxt);
+    process* t = curproc;
+    curproc = otherproc;
+    otherproc = t;
+}
+
+int yield()
+{
+    //lock mutex
+    curproc->state = RUNNABLE;
+    schedule();
+    //unlock mutex
+    return 1;
+}
+
+int print1()
+{
+    terminal_writestring("1");
+    return 1;
+}
+
+int print2()
+{
+    terminal_writestring("2");
+    return 2;
+}
+
+int(*syscalls[NUM_SYSCALLS])()={0,0,0, yield, print1, print2};
+/*NOPE, exit, fork, yield, test, test*/
+
+void syscall()
+{
+    int num = curproc->tf->eax;
+    
+    if(num>0 && num<NUM_SYSCALLS && syscalls[num])
+    {
+        curproc->tf->eax = syscalls[num]();
+    }
+    else
+    {
+        serial_writestring("UNKNOWN SYSCALL CALLED\n");
+        curproc->tf->eax = -1;
+    }
+}

src/PCB.h

@@ -49,16 +49,22 @@ typedef struct//regs needed for context
     uint32_t eip;
     uint32_t eip;
 }__attribute__((packed)) context;
 }__attribute__((packed)) context;
 
 
+enum procstate {KILLED, RUNNABLE, RUNNING};
+
 typedef struct
 typedef struct
 {
 {
     page_directory_entry* mem;
     page_directory_entry* mem;
     volatile int pid;
     volatile int pid;
     struct process* parent;
     struct process* parent;
+    char* kstack;//apparently we need this. idk why
     trapframe* tf;
     trapframe* tf;
     context* ctxt;
     context* ctxt;
     char name[32];
     char name[32];
+    enum procstate state;
 }__attribute__((packed)) process;
 }__attribute__((packed)) process;
 
 
 extern void context_switch(context** old, context* new);
 extern void context_switch(context** old, context* new);
+void syscall();
+void setproc(process* proc);
 
 
 #endif
 #endif

src/idt.c

@@ -105,6 +105,7 @@ int idt_init(uint16_t code_sel)
     idtsetup();
     idtsetup();
     idt_install();
     idt_install();
     load_error_handlers();
     load_error_handlers();
+    handlers[0x100] = syscall;
     return 0;
     return 0;
 }
 }
 #pragma GCC pop_options
 #pragma GCC pop_options

src/switch.asm

 global context_switch
 global context_switch
-switch:
+context_switch:
         mov eax, [esp+4]
         mov eax, [esp+4]
         mov edx, [esp+8]
         mov edx, [esp+8]