os_cpu_a.s

UCOS/II for ICCAVR - The version of UCOS/II is 2.04 - the original port was done by Ole Saether

;********************************************************************************************************
;                                               uC/OS-II
;                                         The Real-Time Kernel
;
;                                       ATmega128  Specific code
;
;
; File     : OS_CPU_A.S
; By       : Ole Saether
;            Jean J. Labrosse
;********************************************************************************************************
;                                           I/O PORT ADDRESSES
;********************************************************************************************************

BIT00   = 0x01
BIT01   = 0x02
BIT02   = 0x04
BIT03   = 0x08
BIT04   = 0x10
BIT05   = 0x20
BIT06   = 0x40
BIT07   = 0x80

SREG    = 0x3F
SPH     = 0x3E
SPL     = 0x3D
RAMPZ   = 0x3B

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

                .macro  PUSH_ALL                            ; Save all registers
                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
                IN      R16,RAMPZ
                ST      -Y,R16
                .endmacro

                .macro  POP_ALL                             ; Restore all registers
                LD      R16,Y+
                OUT     RAMPZ,R16
                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

                .macro  PUSH_SP                             ; Save stack pointer
                IN      R16,SPH
                ST      -Y,R16
                IN      R16,SPL
                ST      -Y,R16
                .endmacro

                .macro  POP_SP                              ; Restore stack pointer
                LD      R16,Y+
                OUT     SPL,R16
                LD      R16,Y+
                OUT     SPH,R16
                .endmacro

                .macro  PUSH_SREG                           ; Save status register
                IN      R16,SREG
                ST      -Y,R16
                .endmacro

                .macro  POP_SREG                            ; Restore status registers
                LD      R16,Y+
                OUT     SREG,R16
                .endmacro

                .area   text(rel)

;/*$PAGE*/.
;********************************************************************************************************
;                            DISABLE/ENABLE INTERRUPTS USING OS_CRITICAL_METHOD #3
;
; Description : These functions are used to disable and enable interrupts using OS_CRITICAL_METHOD #3.
;
;               OS_CPU_SR  OSCPUSaveSR (void)
;                     Get current value of SREG
;                     Disable interrupts
;                     Return original value of SREG
;
;               void  OSCPURestoreSR (OS_CPU_SR cpu_sr)
;                     Set SREG to cpu_sr
;                     Return
;********************************************************************************************************

_OS_CPU_SR_Save::
                IN      R16,SREG                    ; Get current state of interrupts disable flag
                CLI                                 ; Disable interrupts
                RET                                 ; Return original SREG value in R16


_OS_CPU_SR_Restore::
                OUT     SREG,R16                    ; Restore SREG
                RET                                 ; Return

;/*$PAGE*/.
;********************************************************************************************************
;                               START HIGHEST PRIORITY TASK READY-TO-RUN
;
; Description : This function is called by OSStart() to start the highest priority task that was created
;               by your application before calling OSStart().
;
; Note(s)     : 1) The (data)stack frame is assumed to look as follows:
;
;                  OSTCBHighRdy->OSTCBStkPtr --> SPL of (return) stack pointer           (Low memory)
;                                                SPH of (return) stack pointer
;                                                Flags to load in status register
;                                                R31
;                                                R30
;                                                R27
;                                                .
;                                                .
;                                                R0
;                                                PCH
;                                                PCL                                     (High memory)
;
;                  where the stack pointer points to the task start address.
;
;
;               2) OSStartHighRdy() MUST:
;                      a) Call OSTaskSwHook() then,
;                      b) Set OSRunning to TRUE,
;                      c) Switch to the highest priority task.
;********************************************************************************************************

_OSStartHighRdy::
                CALL    _OSTaskSwHook               ; Invoke user defined context switch hook
                LDS     R16,_OSRunning              ; Indicate that we are multitasking