/*---------------------------------------------------------------------------*
  Project:  CtrBrom - libraries - OS
  File:     os_system.c

  Copyright 2008 Nintendo.  All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law.  They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Date::            $
  $Rev$
  $Author$
 *---------------------------------------------------------------------------*/
#include <brom/os.h>

#define osTPrintf(...) ((void)0)


//============================================================================
//          PROCESSER MODE
//============================================================================
/*---------------------------------------------------------------------------*
  Name:         osGetProcMode

  Description:  Get processor mode from CPSR

  Arguments:    None.

  Returns:      CPU processor mode (field 0x10-0x1f)
 *---------------------------------------------------------------------------*/
#include <brom/code32.h>
ASM OSProcMode osGetProcMode( void )
{
    mrs     r0, cpsr
    and     r0, r0, #HW_PSR_CPU_MODE_MASK

    bx      lr
}
#include <brom/codereset.h>

//============================================================================
//          WAIT
//============================================================================
/*---------------------------------------------------------------------------*
  Name:         i_osWaitCpuCycles

  Description:  Loop and Wait for specified CPU cycles at least

  Arguments:    cycles      waiting CPU cycle

  Returns:      None
 *---------------------------------------------------------------------------*/
#include <brom/code32.h>
ASM void  i_osWaitCpuCycles( OSCpuCycle cycle )
{
    sub    r0, r0, #(6-2) // subtract call-return overhead and add the margin of 2 cycles
LSYM(1)
    subs   r0, r0, #4   // 1 cycle
    bcs    BSYM(1)      // 3 cycle
    bx     lr
}
#include <brom/codereset.h>

//============================================================================
//          TERMINATE and HALT
//============================================================================
/*---------------------------------------------------------------------------*
  Name:         osTerminate

  Description:  Halt CPU and loop
  
  Arguments:    None

  Returns:      --  (Never return)
 *---------------------------------------------------------------------------*/
void osTerminate(void)
{
    while (1)
    {
        (void)osDisableInterrupts();
        osHalt();
    }
}

/*---------------------------------------------------------------------------*
  Name:         osHalt

  Description:  Halt CPU
  
  Arguments:    None

  Returns:      None
 *---------------------------------------------------------------------------*/
#include <brom/code32.h>
ASM void osHalt( void )
{
        mov     r0, #0
        mcr     p15, 0, r0, c7, c0, 4
        bx      lr
}
#include <brom/codereset.h>

/*---------------------------------------------------------------------------*
  Name:         osExit

  Description:  Display exit string and Terminate.
                This is useful for 'loadrun' tool command.                 
  
  Arguments:    status : exit status

  Returns:      --  (Never return)
 *---------------------------------------------------------------------------*/
void osExit(int status)
{
#ifdef SDK_FINALROM
#pragma unused( status )
#endif
    (void)osDisableInterrupts();
    osTPrintf("\n" OS_EXIT_STRING, status);
    osTerminate();
}