async.s

ARM嵌入式系统开发--软件设计与优化随书源代码。开发环境asm+c

;  ____________________________________________________________________
; 
;  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 
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;     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. 
; 
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; 
; ****************************************************************************
; * Simple Little Operating System - mpuSLOS
; ****************************************************************************

; ****************************************************************************
; *
; * Module      : async 
; * Description : switch on system (enable cache and asynchronous mode).
; * History     :
; *
; * 8th July 2002 Andrew N. Sloss
; * - ported from Chris Wright's example code. 
; * 
; ****************************************************************************

	IMPORT jumpToTask1
	IMPORT mpuChangeControl

	EXPORT switchOnSystem

	AREA async940,CODE,READONLY

; -------------------------------------------------------------------
; switchOnSystem :
;      enables I & D cache, and Write back
;      special to the 940 set the bus to asynchronous clocking
; -------------------------------------------------------------------
 
switchOnSystem

;infinite
;    B infinite

; enable: Icache,WB,Dcache,MPU

     LDR     r0,=0x100d
     LDR     r1,=0x100d
     BL      mpuChangeControl
 
; asynchronous clocking, 940t only

     LDR     r0,=0xc0000000
     LDR     r1,=0xc0000000
     BL      mpuChangeControl

; -------------------------------------------------------------------
; Jump to Task 1 and switch to User mode and enable IRQ interrupts
; -------------------------------------------------------------------

     MOV     r0,#0x20000
     B       jumpToTask1
     END