wip: better way of handling thread switch (iret in the switch)

src/multitasking/switch_to_thread.s

@@ -1,27 +1,21 @@
 .intel_syntax noprefix
+.set	CLEAR_ERRNO_INTNO, 0x08
 
 .section .text
 	.global switch_thread
 
 switch_thread:
-	mov edx, DWORD PTR [esp]
-	cmp DWORD PTR [current_tcb], 0
-	je .LABEL1
-	mov eax, [current_tcb]
-
-	// save the current stack pointer to the old stack
-	mov [eax+0], esp
-
-	// stack pointer + the 4 regs pushed
-	// and + 1 to get the argument (next thread)
-.LABEL1:
-	mov esi, [esp+4]
-	mov [current_tcb], esi
-
-	mov eax, [current_tcb]
-
-	mov esp, [eax+0] // get esp
-
-	push edx
 	
-	ret
+	mov eax, [esp + 4]
+	mov esp, eax	
+
+	pop eax
+	mov ds, eax
+
+	popa
+	
+	call pic_send_eoi
+
+	add esp, CLEAR_ERRNO_INTNO
+
+	iret