/* ----------------------------------------------------------------------------
 *         ATMEL Microcontroller Software Support
 * ----------------------------------------------------------------------------
 * Copyright (c) 2008, Atmel Corporation
 *
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the disclaimer below.
 * 
 * Atmel's name may not be used to endorse or promote products derived from
 * this software without specific prior written permission. 
 * 
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

//------------------------------------------------------------------------------
//         Startup routine
//------------------------------------------------------------------------------

        .align      4
        .arm
        
/* Main Application entry
 ************************/
        .section    .text

        .global     entry
entry:
        b       init             /* Branch to the init after the arguments */

/* Mailbox area where PC application stores arguments
 *****************************************************/
mailbox:        
        .space  4*32

isInitialized:
        .word  0x00
/* Store the return address to the current stack
 ***********************************************/
init: 
/*  TO DO: we should not have to set sp to _ssstack. 
 *         This is due to a bug in some ROM monitors
 *         At the beginning of the go command, the monitor
 *         does not return from main() thus the stack is 
 *         not empty. In the same time after the go, the 
 *         function returns at the begining of the main() */
    ldr     sp, =_sstack
    stmdb   sp!, {lr}

/* Clear the zero segment only the first time the applet is loaded */  
/* Check the is_initialized flag  */
    ldr     r0, [pc, #-(8+.-isInitialized)]
    mov     r1, #0
    cmp     r0, r1
    bne     2f
    
/* Clear the zero segment */
    ldr     r0, =_szero
    ldr     r1, =_ezero
    mov     r2, #0
1:
    cmp     r0, r1
    strcc   r2, [r0], #4
    bcc     1b
    
/* Update the is_initialized flag */    
    mov     r1, #1
    str     r1, [pc, #-(8+.-isInitialized)]
2:

/* Branch to main()
 ******************/
    mov     r0, #1
    add     r1, pc,#-(8+.-mailbox)
    ldr     r3, =main
    mov     lr, pc
    bx      r3

/* Jump back to SAM-BA Boot
 **************************/
    ldmfd   sp!, {r0}
    bx      r0
        

