Subversion Repositories openrisc_2011-10-31

;/*
;    FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
;
;    ***************************************************************************
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;    *        "Using the FreeRTOS Real Time Kernel - a Practical Guide"        *
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;
;    This file is part of the FreeRTOS distribution.
;
;    FreeRTOS is free software; you can redistribute it and/or modify it under
;    the terms of the GNU General Public License (version 2) as published by the
;    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
;    ***NOTE*** The exception to the GPL is included to allow you to distribute
;    a combined work that includes FreeRTOS without being obliged to provide the
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	EXTERN pxCurrentTCB
	EXTERN ulCriticalNesting
 
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Context save and restore macro definitions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
portSAVE_CONTEXT MACRO
 
	; Push R0 as we are going to use the register. 					
	STMDB	SP!, {R0}
 
	; Set R0 to point to the task stack pointer. 					
	STMDB	SP, {SP}^
	NOP
	SUB		SP, SP, #4
	LDMIA	SP!, {R0}
 
	; Push the return address onto the stack. 						
	STMDB	R0!, {LR}
 
	; Now we have saved LR we can use it instead of R0. 				
	MOV		LR, R0
 
	; Pop R0 so we can save it onto the system mode stack. 			
	LDMIA	SP!, {R0}
 
	; Push all the system mode registers onto the task stack. 		
	STMDB	LR, {R0-LR}^
	NOP
	SUB		LR, LR, #60
 
	; Push the SPSR onto the task stack. 							
	MRS		R0, SPSR
	STMDB	LR!, {R0}
 
	LDR		R0, =ulCriticalNesting 
	LDR		R0, [R0]
	STMDB	LR!, {R0}
 
	; Store the new top of stack for the task. 						
	LDR		R1, =pxCurrentTCB
	LDR		R0, [R1]
	STR		LR, [R0]
 
	ENDM
 
 
portRESTORE_CONTEXT MACRO
 
	; Set the LR to the task stack. 									
	LDR		R1, =pxCurrentTCB
	LDR		R0, [R1]
	LDR		LR, [R0]
 
	; The critical nesting depth is the first item on the stack. 	
	; Load it into the ulCriticalNesting variable. 					
	LDR		R0, =ulCriticalNesting
	LDMFD	LR!, {R1}
	STR		R1, [R0]
 
	; Get the SPSR from the stack. 									
	LDMFD	LR!, {R0}
	MSR		SPSR_cxsf, R0
 
	; Restore all system mode registers for the task. 				
	LDMFD	LR, {R0-R14}^
	NOP
 
	; Restore the return address. 									
	LDR		LR, [LR, #+60]
 
	; And return - correcting the offset in the LR to obtain the 	
	; correct address. 												
	SUBS	PC, LR, #4
 
	ENDM