os_cpu_a_bak.s

ucos-ii-at90S-icc-avr

;*******************************************************************************
;                                   uC/OS-II
;                             The Real-Time Kernel
;
;                         AT90 Specific code
;                               (ICC V6.21)
;
;
; File:			OS_CPU_A.S
; By:			
; Modified by:	
; Port Version:	V1.00
;
;
;*******************************************************************************

;include 

;*******************************************************************************
;                 I/O PORT ADDRESSES
;*******************************************************************************

SREG	=0x3F
SPH	=0x3E
SPL	=0x3D
TCNT0	=0x32

PIND    = 0x10
PORTD   = 0x12

;*******************************************************************************
;                MACROS
;*******************************************************************************

				; Push registers
.macro PUSHRS
                ST      -Y,R0	
                ST      -Y,R1
                ST      -Y,R2
                ST      -Y,R3
                ST      -Y,R4
                ST      -Y,R5
                ST      -Y,R6
                ST      -Y,R7
                ST      -Y,R8
                ST      -Y,R9
                ST      -Y,R10
                ST      -Y,R11
                ST      -Y,R12
                ST      -Y,R13
                ST      -Y,R14
                ST      -Y,R15
                ST      -Y,R16
                ST      -Y,R17
                ST      -Y,R18
                ST      -Y,R19
                ST      -Y,R20
                ST      -Y,R21
                ST      -Y,R22
                ST      -Y,R23
                ST      -Y,R24
                ST      -Y,R25
                ST      -Y,R26
                ST      -Y,R27
                ST      -Y,R30
                ST      -Y,R31
.endmacro

				; Pop registers
.macro POPRS
                LD      R31,Y+
                LD      R30,Y+
                LD      R27,Y+
                LD      R26,Y+
                LD      R25,Y+
                LD      R24,Y+
                LD      R23,Y+
                LD      R22,Y+
                LD      R21,Y+
                LD      R20,Y+
                LD      R19,Y+
                LD      R18,Y+
                LD      R17,Y+
                LD      R16,Y+
                LD      R15,Y+
                LD      R14,Y+
                LD      R13,Y+
                LD      R12,Y+
                LD      R11,Y+
                LD      R10,Y+
                LD      R9,Y+
                LD      R8,Y+
                LD      R7,Y+
                LD      R6,Y+
                LD      R5,Y+
                LD      R4,Y+
                LD      R3,Y+
                LD      R2,Y+
                LD      R1,Y+
                LD      R0,Y+
.endmacro

				; Push stack pointer
.macro PUSHSP
                IN      R16,SPH
                ST      -Y,R16
                IN      R16,SPL
                ST      -Y,R16
.endmacro

				; Pop stack pointer
.macro POPSP
                LD      R16,Y+
                OUT     SPL,R16
                LD      R16,Y+
                OUT     SPH,R16
.endmacro

				;Push SREG
.macro PUSHSREG
                IN      R16,SREG
                ST      -Y,R16
.endmacro

				; Pop SREG
.macro POPSREG
                LD      R16,Y+
                OUT     SREG,R16
.endmacro

.area    text(rel)
;*******************************************************************************
;                 TASK LEVEL CONTEXT SWITCH
;
; Description : This function is called when a task makes a higher priority task
; ready-to-run.
;
; Note(s):
;	1) Upon entry,
;		OSTCBCur     points to the OS_TCB of the task to suspend
;		OSTCBHighRdy points to the OS_TCB of the task to resume
;
;	2) The stack frame of the task to suspend looks as follows:
;
;		SP	+0 --> LSB of task code address
;			+1     MSB of task code address	(High memory)
;
;	3) The saved context of the task to resume looks as follows:
;
;		OSTCBHighRdy->OSTCBStkPtr --> LSB of (return) stack pointer (Low memory)
;                                     MSB of (return) stack pointer
;                                     Flags to load in status register
;                                     R31
;                                     R30
;                                     R7
;                                     .
;                                     .
;                                     .
;                                     R0    (High memory)
;*******************************************************************************

_OSCtxSw::      PUSHRS                              ; Save current task's context
                PUSHSREG
                PUSHSP

		LDS     R30,_OSTCBCur		; Z = OSTCBCur->OSTCBStkPtr
		LDS     R31,_OSTCBCur+1		;
		ST      Z+,R28				; Save Y (R29:R28) pointer
		ST      Z+,R29				;
	
		LDS     R16,_OSPrioHighRdy	; OSPrioCur = OSPrioHighRdy
		STS     _OSPrioCur,R16
	
		LDS     R30,_OSTCBHighRdy ; Let Z point to TCB of highest priority task
		LDS     R31,_OSTCBHighRdy+1	; ready to run
		STS     _OSTCBCur,R30		; OSTCBCur = OSTCBHighRdy
		STS     _OSTCBCur+1,R31 	;

		LD      R28,Z+		; Restore Y pointer
		LD      R29,Z+		;

                POPSP                               ; Restore stack pointer
                POPSREG                             ; Restore status register
                POPRS                               ; Restore all registers 
                RET