more scheduler crap

preemptive scheduling is hard, so i went back to cooperative scheduling.

include/sched/sched.h

@@ -1,16 +1,13 @@
 #ifndef SCHED_H
 #define SCHED_H
 
-#include <cpu/idt.h>
-#include <cpu/pic.h>
-#include <cpu/pit.h>
 #include <tty/panic.h>
 #include <sched/process.h>
 
 void sched_init(process_t *proc);
 void sched_add(process_t *proc);
 void sched_remove(process_t *proc);
 unsigned long sched_pid_alloc(void);
-unsigned long sched_step(void);
+void sched_step(void);
 
 #endif

src/boot/init.c

@@ -35,9 +35,8 @@ void init_arch(struct multiboot_info *mb)
 
 void idle(void)
 {
-	for (;;) {
-		asm ("nop");
-	}
+	tty_printf("a");
+	asm ("nop");
 }
 
 void init(struct multiboot_info *mb)
@@ -48,7 +47,8 @@ void init(struct multiboot_info *mb)
 
 	sched_init(process_init(idle, "idle"));
 
-	idle();
+	for (;;)
+		sched_step();
 
 	return;
 }

src/sched/sched.c

@@ -5,56 +5,13 @@ extern void sched_jump(unsigned long eip);
 static process_t *curr = NULL;
 static unsigned long pid = 0;
 
-void sched_int(void)
-{
-	asm ("cli");
-
-	asm ("out %%al, %%dx" : : "d"(0x20), "a"(0x20));
-
-	// save registers
-	asm ("mov %%ebx, %0" : "=r"(curr->regs.ebx));
-	asm ("mov %%ecx, %0" : "=r"(curr->regs.ecx));
-	asm ("mov %%edx, %0" : "=r"(curr->regs.edx));
-
-	asm ("mov %%esi, %0" : "=r"(curr->regs.esi));
-	asm ("mov %%edi, %0" : "=r"(curr->regs.edi));
-
-	asm ("mov %%esp, %0" : "=r"(curr->regs.esp));
-	asm ("mov %%ebp, %0" : "=r"(curr->regs.ebp));
-
-	asm ("mov 12(%%esp), %0" : "=r"(curr->regs.eip));
-
-	if (sched_step() == 1) {
-
-		// restore registers
-
-		asm ("mov %0, %%ebx" : "=r"(curr->regs.ebx));
-		asm ("mov %0, %%ecx" : "=r"(curr->regs.ecx));
-		asm ("mov %0, %%edx" : "=r"(curr->regs.edx));
-
-		asm ("mov %0, %%esi" : "=r"(curr->regs.esi));
-		asm ("mov %0, %%edi" : "=r"(curr->regs.edi));
-
-	//	asm ("mov %0, %%esp" : "=r"(curr->regs.esp));
-	//	asm ("mov %0, %%ebp" : "=r"(curr->regs.ebp));
-
-		sched_jump(curr->regs.eip);
-	}
-
-	asm ("sti; leave; iret");
-}
-
 void sched_init(process_t *proc)
 {
 	if (proc) {
 		curr = proc;
 
 		curr->prev = curr;
 		curr->next = curr;
-
-		idt_set_entry(32, (unsigned long)sched_int);
-		pit_set_phase(PIT_HZ / 1000);
-		pic_enable_irq(0);
 	}
 }
 
@@ -81,29 +38,29 @@ unsigned long sched_pid_alloc(void)
 	return pid++;
 }
 
-unsigned long sched_step(void)
+void sched_step(void)
 {
-	unsigned long schedule = 0;
-
 	if (curr && curr->next) {
 		switch (curr->state) {
+		case PROCESS_RUNNING:
+			PANIC("trying to schedule a running process!");
 		case PROCESS_RUNABLE:
-			schedule = 1;
+			curr->state = PROCESS_RUNNING;
+			sched_jump(curr->regs.eip);
+			curr->state = PROCESS_RUNABLE;
 			break;
 		case PROCESS_SLEEPING:
 			// do nothing and let it sleep
 			break;
 		case PROCESS_ZOMBIE:
 			curr = curr->next;
 			sched_remove(curr->prev);
-			return 0;
+			return;
 		default:
 			PANIC("cannot handle unknown process state!");
 		}
 		curr = curr->next;
 	} else {
 		PANIC("no more processes to schedule!");
 	}
-
-	return schedule;
 }

src/sched/switch.asm

@@ -2,12 +2,6 @@
 ; void sched_jump(unsigned long eip);
 global sched_jump
 sched_jump:
-	pop eax
-	
-	pushfd
-	or dword [esp], 0x200
-	push 0x8
-	push eax
-
-	iret
+	mov eax, [esp + 4]
+	jmp eax