start.s

ucos在所有cpu下的移植范例

;******************************************************************************
;                                  uC/OS-II
;                           The Real-Time Kernel
;
;             (c) Copyright 1998, Jean J. Labrosse, Plantation, FL
;                            All Rights Reserved
;
;                            68HC12 Startup Code
;
; Filename   : START.S
; Programmer : Jean J. Labrosse
;******************************************************************************
;
;/*$PAGE*/
;******************************************************************************
;                             PUBLIC DECLARATIONS
;******************************************************************************

        xdef         _Startup

;******************************************************************************
;                            EXTERNAL DECLARATIONS
;******************************************************************************

        xref         _main

;/*$PAGE*/
;******************************************************************************
;                                  _Startup
;
; Description : This is the function that is called to initialize the system
;               when a RESET occurs.  The stack pointer is set to the top of 
;               the stack, the C function 'AppMain()' defined in the 
;               application software is called.
; Arguments   : None.
; Returns     : None.
;******************************************************************************

_Startup:
                                                            ; Target microprocessor startup code
        sei                                                 ; Disable interrupts.

        lds     #$0BFF                                      ; Initialize stack pointer to the top of the stack.

        LDAA    #$0D0                                       ; CCR code - STOP disabled, XIRQ disabled, and general interrupts disabled.
        TAP                                                 ; Transfer to CCR.
                                                            ; bit7 = S -> STOP disable.
                                                            ; bit6 = X -> XIRQ disable.
                                                            ; bit5 = H -> half carry.
                                                            ; bit4 = I -> interrupt disable.
                                                            ; bit3 = N -> negative.
                                                            ; bit2 = Z -> zero.
                                                            ; bit1 = V -> overflow.
                                                            ; bit0 = C -> carry.

;        clra                                                ; Set all RAM to 0
;        ldx     #$0800
;_StartupClearRAM:
;        staa    0,X
;        inx
;        cpx     #1024                                       ; 68HC12 has 1024 bytes of RAM
;        bne     _StartupClearRAM

        jmp     _main                                        ; Execute 'main()' in application software.

        end