1 files changed, 28 insertions, 0 deletions
diff --git a/kernel/exceptions/irq.S b/kernel/exceptions/irq.S
new file mode 100644
index 0000000..a7e78bc
--- /dev/null
+++ b/kernel/exceptions/irq.S
@@ -0,0 +1,28 @@
+.section ".text.exceptions"
+.globl irq
+irq:
+	cpsid ai
+	stmfd sp!, {r0-r12,lr}
+	// Run IRQ handler
+	bl c_irq_handler
+	cmp r0, #1
+	bne 1f
+	// Schedule if interrupted a thread
+	mrs r1, spsr
+	and r1, r1, #0x1f
+	cmp r1, #0x10
+	bne 1f
+	ldmfd sp!, {r0-r12,lr}
+	// Don't skip missed instruction upon return
+	sub lr, #4
+	push {r3}
+	// Store the instruction in a special area for
+	//  future processing
+	ldr r3, =irqlr
+	str lr, [r3, #0]
+	pop {r3}
+	cps #0x13
+	b schedule
+1:
+	ldmfd sp!, {r0-r12,lr}
+	subs pc, lr, #4