cpu_a.s

来自「移植到freescale 9s12系列单片机的uCOSII」· S 代码 · 共 64 行

;********************************************************************************************************
;                                               uC/CPU
;                                    CPU CONFIGURATION & PORT LAYER
;
;                          (c) Copyright 1999-2005; Micrium, Inc.; Weston, FL
;
;                   All rights reserved.  Protected by international copyright laws.
;                   Knowledge of the source code may not be used to write a similar
;                   product.  This file may only be used in accordance with a license
;                   and should not be redistributed in any way.
;********************************************************************************************************


;********************************************************************************************************
;                                           CPU PORT FILE
;                                         Freescale MC9S12
;                                        Metrowerks Compiler
;
; Filename      : cpu_a.s
; Version       : V1.00
; Programmer(s) : EHS
;********************************************************************************************************


;********************************************************************************************************
;                                           PUBLIC FUNCTIONS
;********************************************************************************************************

        xdef  CPU_SR_Save
        xdef  CPU_SR_Restore


;********************************************************************************************************
;                                               EQUATES
;********************************************************************************************************


;********************************************************************************************************
;                                  SAVE THE CCR AND DISABLE INTERRUPTS
;                                                  &
;                                              RESTORE CCR
;
; Description : These function implements OS_CRITICAL_METHOD #3 
;
; Arguments   : The function prototypes for the two functions are:
;               1) OS_CPU_SR  OSCPUSaveSR(void)
;                             where OS_CPU_SR is the contents of the CCR register prior to disabling
;                             interrupts.
;               2) void       OSCPURestoreSR(OS_CPU_SR os_cpu_sr);
;                             'os_cpu_sr' the the value of the CCR to restore.
;
; Note(s)     : 1) It's assumed that the compiler uses the D register to pass a single 16-bit argument
;                  to and from an assembly language function.
;********************************************************************************************************

CPU_SR_Save:
    tfr  ccr,b                         ; It's assumed that 8-bit return value is in register B
    sei                                ; Disable interrupts
    rtc                                ; Return to caller with D containing the previous CCR

CPU_SR_Restore:
    tfr  b,ccr                         ; B contains the CCR value to restore, move to CCR
    rtc