bringup.s

这是一个基于C的操作系统的开发实现,借助的是OS设计思想,以用一些最为关键的技术,模拟一个OS的工作原理

@  ____________________________________________________________________
@ 
@  Copyright (c) 2002, Andrew N. Sloss, Chris Wright and Dominic Symes
@  All rights reserved.
@  ____________________________________________________________________
@ 
@  NON-COMMERCIAL USE License
@  
@  Redistribution and use in source and binary forms, with or without 
@  modification, are permitted provided that the following conditions 
@  are met: 
@  
@  1. For NON-COMMERCIAL USE only.
@ 
@  2. Redistributions of source code must retain the above copyright 
@     notice, this list of conditions and the following disclaimer. 
@ 
@  3. Redistributions in binary form must reproduce the above 
@     copyright notice, this list of conditions and the following 
@     disclaimer in the documentation and/or other materials provided 
@     with the distribution. 
@ 
@  4. All advertising materials mentioning features or use of this 
@     software must display the following acknowledgement:
@ 
@     This product includes software developed by Andrew N. Sloss,
@     Chris Wright and Dominic Symes. 
@ 
@   THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY 
@   EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
@   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
@   PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE CONTRIBUTORS 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. 
@ 
@  If you have questions about this license or would like a different
@  license please email :
@ 
@ 	[e-mail]
@ 
@ 
@ ****************************************************************************
@ * Simple Little Operating System - SLOS
@ ****************************************************************************

@ ****************************************************************************
@ *
@ * Module          : bringup
@ * Description     : provides the low level debug capabilities used
@ *                   in the bringup stage. This debug information is 
@ *                   stored in the FIQ registers. 
@ * OS              : SLOS 0.09
@ * Platform        : generic
@ *
@ ****************************************************************************

@ ****************************************************************************
@ * EXPORT
@ ****************************************************************************

     .text
     .code 32
     .align 0
     .global bringUpSetR8fiq
     .global bringUpSetR9fiq
     .global bringUpSetR10fiq
     .global bringUpInitFIQRegisters

@ -- switchToFIQMode ---------------------------------------------------------
@ Description  : sets the r8 in FIQ mode and return back to SVC mode
@ Parameters   : r1 - fatal number
@ Return       : none... 

switchToFIQMode:

     MOV     r3,lr
     MRS     r1,CPSR
     BIC     r1,r1,#0x1f
     ORR     r1,r1,#0x11 
     MSR     CPSR_c,r1
     MOV     pc,r3 

@ -- switchToSVCMode ---------------------------------------------------------
@ Description  : sets the r8 in FIQ mode and return back to SVC mode
@ Parameters   : r1 - fatal number
@ Return       : none... 


switchToSVCMode:

     MOV     r3,lr                     
     MRS     r1,CPSR
     BIC     r1,r1,#0x1f
     ORR     r1,r1,#0x13 
     MSR     CPSR_c,r1
     MOV     pc,r3

@ -- bringUpSetR8fiq ---------------------------------------------------------
@ Description  : sets the r8 in FIQ mode and return back to SVC mode
@ Parameters   : r1 - fatal number
@ Return       : none... 

bringUpInitFIQRegisters:

@ r1 - fatal error number

     MOV     r2,lr            @ copy link register into r2
     BL      switchToFIQMode  @ change FIQ
     MOV     r8,#0            @ r8FIQ=0
     MOV     r9,#0            @ r9FIQ=0
     MOV     r10,#0           @ r10FIQ=0
     BL      switchToSVCMode  @ change SVC
     MOV     pc,r2            @ return back

@ -- bringUpSetR8fiq ---------------------------------------------------------
@ Description  : sets the r8 in FIQ mode and return back to SVC mode
@ Parameters   : r1 - fatal number
@ Return       : none... 

bringUpSetR8fiq:

@ r1 - fatal error number

     MOV     r2,lr            @ copy link register into r2
     BL      switchToFIQMode  @ change FIQ 	
     MOV     r8,r0            @ r10_fiq = r0
     BL      switchToSVCMode  @ change SVC
     MOV     pc,r2            @ return back

@ -- bringUpSetR9fiq ---------------------------------------------------------
;
@ Description  : sets the r10 FIQ mode and return back to SVC mode
;
@ Parameters   : r2 - exit trace number
@ Return       : none... 
;

bringUpSetR9fiq:

@ r2 - entry trace number

     MOV     r2,lr
     BL      switchToFIQMode  @ change FIQ 	
     MOV     r9,r0            @ r9_fiq = r2
     BL      switchToSVCMode  @ change SVC
     MOV     pc,r2            @ return back

@ -- bringup_setR10fiq -------------------------------------------------------
;
@ Description  : sets the r10 FIQ mode and return back to SVC mode
;
@ Parameters   : r2 - exit trace number
@ Return       : none... 
;

bringUpSetR10fiq:

@ r2 - exit trace number

     MOV     r2,lr
     BL      switchToFIQMode  @ change FIQ 	
     MOV     r10,r0           @ r10_fiq = r2
     BL      switchToSVCMode  @ change SVC
     MOV     pc,r2            @ return back
     .end