Add simple exception handling

This adds support for exception handling.
It should provide simple and fast reporting of crucial info and full restoration without powering off.

nyx/nyx_gui/start.S

@@ -23,8 +23,8 @@
 .extern memset
 .type memset, %function
 
-.extern ipl_main
-.type ipl_main, %function
+.extern _irq_setup
+.type _irq_setup, %function
 
 .globl _start
 .type _start, %function
@@ -36,7 +36,7 @@ _start:
 
 	/* If we are not in the right location already, copy a relocator to upper IRAM. */
 	ADR R2, _reloc_ipl
-	LDR R3, =0x4003FFE0
+	LDR R3, =0x4003FF00
 	MOV R4, #(_real_start - _reloc_ipl)
 _copy_loop:
 	LDMIA R2!, {R5}
@@ -48,7 +48,7 @@ _copy_loop:
 	LDR R2, =__ipl_end
 	SUB R2, R2, R1
 	LDR R3, =_real_start
-	LDR R4, =0x4003FFE0
+	LDR R4, =0x4003FF00
 	BX R4
 
 _reloc_ipl:
@@ -67,7 +67,7 @@ _real_start:
 	LDR R2, =__bss_end
 	SUB R2, R2, R0
 	BL memset
-	BL ipl_main
+	BL _irq_setup
 	B .
 
 .globl pivot_stack