0x00000018  00000000  ANDEQ     R0,R0,R0

;/*****************************************************************************/
;/* IRQ0.S: IRQ 0 Nested Interrupt                                            */
;/*****************************************************************************/
;/* This file is part of the uVision/ARM development tools.                   */
;/* Copyright (c) 2005-2006 Keil Software. All rights reserved.               */
;/* This software may only be used under the terms of a valid, current,       */
;/* end user licence from KEIL for a compatible version of KEIL software      */
;/* development tools. Nothing else gives you the right to use this software. */
;/*****************************************************************************/

                AREA    IRQ0, CODE, READONLY
                ARM

                PRESERVE8
                ALIGN
                IMPORT  irq0_nint
                EXPORT  irq0_int
irq0_int        FUNCTION

                SUB     LR, LR, #4        ; Update Link Register
                STMFD   SP!, {R0-R12, LR}    ; Save Workspace & LR to Stack
                MRS     R0, SPSR             ; Copy SPSR to R0
                STMFD   SP!, {R0, R1}        ; Save SPSR to Stack (8-byte)
                MSR     CPSR_c, #0x1F        ; Enable IRQ (Sys Mode)
                STMFD   SP!, {R0, LR}        ; Save LR_sys to Stack (8-byte)
                LDR     R0, =irq0_nint    ; Get IRQ Function Address
                MOV     LR, PC            ; Return Address
                BX      R0                ; Call IRQ Function
                LDMFD   SP!, {R0, LR}        ; Restore LR_sys
                MSR     CPSR_c, #0x92        ; Disable IRQ (IRQ Mode)
                LDMFD   SP!, {R0, R1}        ; Restore SPSR to R0
                MSR     SPSR_cxsf, R0        ; Copy R0 to SPSR
                LDMFD   SP!, {R0-R12, PC}^; Return to program

                ENDFUNC

                END

AT91C_BASE_MC->MC_RCR = AT91C_MC_RCB; // Remap the internal SRAM at 0x0