===================================================================
RCS file: /cvs/funnyos/arch/testarm/boot/loader.S,v
retrieving revision 1.2
retrieving revision 1.5
diff -u -r1.2 -r1.5
--- funnyos/arch/testarm/boot/loader.S	2007/10/29 20:34:23	1.2
+++ funnyos/arch/testarm/boot/loader.S	2007/11/23 13:37:42	1.5
@@ -1,5 +1,5 @@
 /*
- * $Id: loader.S,v 1.2 2007/10/29 20:34:23 init Exp $
+ * $Id: loader.S,v 1.5 2007/11/23 13:37:42 nbrk Exp $
  */
 /*
  *	FunnyOS loader
@@ -10,23 +10,39 @@
 .global main
 
 _start:
-bl 	_vector_reset		/* reset */
+b 	_vector_reset		/* reset */
 bl 	_vector_undef		/* undefined insn */
 bl 	_vector_swi			/* software intr handler */
 bl 	_vector_dataabrt	/* data abort */
 bl 	_vector_prefabrt	/* prefetch abort */
 .word 0x00000000		/* [reserved] */
-bl 	_vector_irq			/* IRQ */
+b 	_vector_irq			/* IRQ */
 bl 	_vector_fiq			/* Fast Interrupt Request */
 
 _vector_reset:
 	/*
-		Will enter here just right after RESET.
-		Set up stack and call main.
-	*/
+	 *	Will enter here just right after RESET.
+	 *	Set up stack and call main.
+	 */
 
-	ldr r13, Astack	/* XXX stack at the end of phys mem */
+	/*
+	 * Setup an IRQ stack
+	 */
+	/* switch into irq mode with interrupts disabled */
+	msr cpsr_c, #(0x12 | 0x80) 
 
+	/* set sp (sp is banked) */
+	ldr sp, Airqstack
+
+	/*
+	 * Setup system stack
+	 */
+	/* switch into system mode (interrupts turned off) */
+	msr cpsr_c, #(0x1f | 0x80)
+
+	/* set system stack pointer */
+	ldr sp, Asysstack
+
 	b main
 	/* NOTREACHED */
 
@@ -45,12 +61,32 @@
 	nop
 
 _vector_irq:
+	/* decrement pc by one insn */
+	sub lr, lr, #4
+
+	/* store all system mode registers */
+	stmdb sp!, {r0-r12, lr}
+
+	/* store sys_mode's cpsr */
+//	mrs r1, spsr
+//	stmdb sp!, {r1}
+
+	/* pass sp (which now contains struct pcb of interrupted task) to irq_trampoline */
+	mov r0, sp
+
 	bl irq_trampoline
 
+	/* load r0-r12 and pc from the stack */
+	/* note ^ that copies SPSR into CPSR */
+	/** here we may return to different task (if pcb was changed in the stack memory) **/
+	ldmia sp!, {r0-r12, pc}^
+
 _vector_fiq:
 	nop
 
 /* last word of the physical memory */
-Astack:
+Asysstack:
 .word 	0x01fffffc
+Airqstack:
+.word 	0x01fff000