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;------------------------------------------------------------------------------
;-         ATMEL Microcontroller Software Support  -  ROUSSET  -
;------------------------------------------------------------------------------
; The software is delivered "AS IS" without warranty or condition of any
; kind, either express, implied or statutory. This includes without
; limitation any warranty or condition with respect to merchantability or
; fitness for any particular purpose, or against the infringements of
; intellectual property rights of others.
;-----------------------------------------------------------------------------
;- File source          : Cstartup.s79
;- Object               : Generic CStartup for IAR No Use REMAP
;- Compilation flag     : None
;-
;- 1.0 15/Jun/04 JPP    : Creation
;------------------------------------------------------------------------------

#include "AT91SAM7X256_inc.h"

;------------------------------------------------------------------------------
;- Area Definition
;------------------------------------------------------------------------------

;---------------------------------------------------------------
; ?RESET
; Reset Vector.
; Normally, segment INTVEC is linked at address 0.
; For debugging purposes, INTVEC may be placed at other
; addresses.
; A debugger that honors the entry point will start the
; program in a normal way even if INTVEC is not at address 0.
;-------------------------------------------------------------

                PROGRAM ?RESET
                RSEG    INTRAMSTART_REMAP
                RSEG    INTRAMEND_REMAP

                EXTERN  vPortYieldProcessor

                RSEG    ICODE:CODE:ROOT(2)
                CODE32  ; Always ARM mode after reset   
                org     0        
reset           
;------------------------------------------------------------------------------
;- Exception vectors
;--------------------
;- These vectors can be read at address 0 or at RAM address
;- They ABSOLUTELY requires to be in relative addresssing mode in order to
;- guarantee a valid jump. For the moment, all are just looping.
;- If an exception occurs before remap, this would result in an infinite loop.
;- To ensure if a exeption occurs before start application to infinite loop.
;------------------------------------------------------------------------------

                B           InitReset           ; 0x00 Reset handler
undefvec:
                B           undefvec            ; 0x04 Undefined Instruction
swivec:
                B           vPortYieldProcessor ; 0x08 Software Interrupt
pabtvec:
                B           pabtvec             ; 0x0C Prefetch Abort
dabtvec:
                B           dabtvec             ; 0x10 Data Abort
rsvdvec:
                B           rsvdvec             ; 0x14 reserved
irqvec:
                                LDR                     PC, [PC, #-0xF20]       ; Jump directly to the address given by the AIC

fiqvec:                                                                 ; 0x1c FIQ

;------------------------------------------------------------------------------
;- Function             : FIQ_Handler_Entry
;- Treatments           : FIQ Controller Interrupt Handler.
;- Called Functions     : AIC_FVR[interrupt]
;------------------------------------------------------------------------------

FIQ_Handler_Entry:

;- Switch in SVC/User Mode to allow User Stack access for C code
; because the FIQ is not yet acknowledged

;- Save and r0 in FIQ_Register
            mov         r9,r0
                    ldr         r0 , [r8, #AIC_FVR]
            msr         CPSR_c,#I_BIT | F_BIT | ARM_MODE_SVC

;- Save scratch/used registers and LR in User Stack
            stmfd       sp!, { r1-r3, r12, lr}

;- Branch to the routine pointed by the AIC_FVR
            mov         r14, pc
            bx          r0

;- Restore scratch/used registers and LR from User Stack
            ldmia       sp!, { r1-r3, r12, lr}

;- Leave Interrupts disabled and switch back in FIQ mode
            msr         CPSR_c, #I_BIT | F_BIT | ARM_MODE_FIQ

;- Restore the R0 ARM_MODE_SVC register
            mov         r0,r9

;- Restore the Program Counter using the LR_fiq directly in the PC
            subs        pc,lr,#4

InitReset:
;------------------------------------------------------------------------------
;- Low level Init (PMC, AIC, ? ....) by C function AT91F_LowLevelInit
;------------------------------------------------------------------------------
                EXTERN   AT91F_LowLevelInit

#define  __iramend      SFB(INTRAMEND_REMAP)

;- minumum C initialization
;- call  AT91F_LowLevelInit( void)

            ldr     r13,=__iramend            ; temporary stack in internal RAM
;--Call Low level init function in ABSOLUTE through the Interworking
                    ldr     r0,=AT91F_LowLevelInit
            mov     lr, pc
                    bx      r0
;------------------------------------------------------------------------------
;- Stack Sizes Definition
;------------------------
;- Interrupt Stack requires 2 words x 8 priority level x 4 bytes when using
;- the vectoring. This assume that the IRQ management.
;- The Interrupt Stack must be adjusted depending on the interrupt handlers.
;- Fast Interrupt not requires stack If in your application it required you must
;- be definehere.
;- The System stack size is not defined and is limited by the free internal
;- SRAM.
;------------------------------------------------------------------------------

;------------------------------------------------------------------------------
;- Top of Stack Definition
;-------------------------
;- Interrupt and Supervisor Stack are located at the top of internal memory in
;- order to speed the exception handling context saving and restoring.
;- ARM_MODE_SVC (Application, C) Stack is located at the top of the external memory.
;------------------------------------------------------------------------------

IRQ_STACK_SIZE          EQU     300

ARM_MODE_FIQ            EQU     0x11
ARM_MODE_IRQ            EQU     0x12
ARM_MODE_SVC            EQU     0x13

I_BIT                   EQU     0x80
F_BIT                   EQU     0x40

;------------------------------------------------------------------------------
;- Setup the stack for each mode
;-------------------------------
                ldr     r0, =__iramend

;- Set up Fast Interrupt Mode and set FIQ Mode Stack
                msr     CPSR_c, #ARM_MODE_FIQ | I_BIT | F_BIT
;- Init the FIQ register
                ldr     r8, =AT91C_BASE_AIC

;- Set up Interrupt Mode and set IRQ Mode Stack
                msr     CPSR_c, #ARM_MODE_IRQ | I_BIT | F_BIT
                mov     r13, r0                     ; Init stack IRQ
                sub     r0, r0, #IRQ_STACK_SIZE

;- Enable interrupt & Set up Supervisor Mode and set Supervisor Mode Stack
                msr     CPSR_c, #ARM_MODE_SVC
                mov     r13, r0


;---------------------------------------------------------------
; ?CSTARTUP
;---------------------------------------------------------------
                EXTERN  __segment_init
                EXTERN  main
; Initialize segments.
; __segment_init is assumed to use
; instruction set and to be reachable by BL from the ICODE segment
; (it is safest to link them in segment ICODE).
                ldr     r0,=__segment_init
                mov     lr, pc
                bx      r0

                PUBLIC  __main
?jump_to_main:
                ldr     lr,=?call_exit
                ldr     r0,=main
__main:
                bx      r0

;------------------------------------------------------------------------------
;- Loop for ever
;---------------
;- End of application. Normally, never occur.
;- Could jump on Software Reset ( B 0x0 ).
;------------------------------------------------------------------------------
?call_exit:
End
            b       End



;---------------------------------------------------------------
; ?EXEPTION_VECTOR
; This module is only linked if needed for closing files.
;---------------------------------------------------------------
                PUBLIC  AT91F_Default_FIQ_handler
                PUBLIC  AT91F_Default_IRQ_handler
                PUBLIC  AT91F_Spurious_handler

                CODE32  ; Always ARM mode after exeption        

AT91F_Default_FIQ_handler
            b     AT91F_Default_FIQ_handler

AT91F_Default_IRQ_handler
            b     AT91F_Default_IRQ_handler

AT91F_Spurious_handler
            b     AT91F_Spurious_handler

        ENDMOD

        END