appl2.a51

8051实时操作系统

;**************
;* APPL2.A51  *
;**************
;
; iDCM 44 Sample Application: Part 2
;

$nolist
$include(dcx51a.ext)
$include(dcx51a.lit)
$include(dcx51a.mac)
$list

;
; Sample Application: Consists of Task 3 and Task 4, which do the following:
;
;  Task 3:                    Loop
;                               Send message to task 4
;                               Wait for reply message
;                             End Loop
;
;  Task 4:                    Loop
;                               Wait for message
;                               Send reply
;                               Flash red led if 256th message
;                             End Loop
;
;  To generate this sample, perform the following:
;
;  ASM51 APPL2.A51 DEBUG
;  RL51  DCM44I.LIB(DCM44_SPACE), APPL2.OBJ, DCX51I.LIB TO APPL2
;  OH    APPL2 TO APPL2.HEX
;
;  To execute on an Intel iRCB board, place a 2K x 8 SRAM into the empty    
;  universal memory site, and set the board for memory option B.  Next, 
;  use the Bitbus Monitor to download both APPL1.HEX and APPL2.HEX 
;  into the SRAM.  Upon reset, tasks 1, 2, 3, and 4 will execute (and both
;  LEDs will start flashing).  Note that since the system clock tick is
;  redefined in the IDD below back to 1 msec., the green LED flashed by
;  task 2 now toggles 10 times per second rather that once per second as
;  when only tasks 1 and 2 are running.
;
;  APPL1 and APPL2 can also be executed out of EPROM, or by using an emulator, 
;  such as ICE5100.
;

APPL2_DATA_SEG    SEGMENT   DATA
                  RSEG      APPL2_DATA_SEG

MSG_COUNT:        DS        1
MSG_PTR:          DS        1

                  CSEG      AT 0F800H

ITD3:
%ITD(TASK3, 6, 083H, 000B, 01H, 00000B, ITD4)

ITD4:
%ITD(TASK4, 4, 084H, 000B, 01H, 00000B, IDD)

IDD:
%IDD(-1000, 0, 0, 0, 0) ;set system clock granularity back to 1 msec.

;
; Equates
;
RED_LED              EQU    90H
MESSAGE_LENGTH       EQU    08H
COMMAND_FLAG         EQU    00H
REPLY_FLAG           EQU    80H
USER_DEFINED_COMMAND EQU    03H
SAMPLE_DATA_BYTE     EQU    06H

;
; The code for Tasks 3 and 4 follows
;

TASK3:
  CALL  RQALLOCATE                              ;Get a message buffer
  MOV   MSG_PTR,A                               ;Point MSG_PTR to buffer
  ADD   A,#2                                    ;
  MOV   R0,A                                    ;R0 => length field
  MOV   @R0,#MESSAGE_LENGTH                     ;Message length = 8
  INC   R0                                      ;R0 => flag field
  MOV   @R0,#COMMAND_FLAG                       ;set msg type = command
  INC   R0                                      ;R0 => dest. node addr field
  MOV   @R0,#0                                  ;message to be sent locally
  INC   R0                                      ;R0 => source & dest. task ids
  MOV   A,#84H                                  ;Get task id for fid = 84
  ACALL TASK_OF                                 ;"
  MOV   B,A                                     ;B = dest id
  MOV   A,RQTASKID                              ;A = source id
  SWAP  A                                       ;Place source id in high nibble
  ORL   A,B                                     ;Place dest id in low nibble
  MOV   @R0,A                                   ;Insert src & dest task ids
  INC   R0                                      ;R0 => command field
  MOV   @R0,#USER_DEFINED_COMMAND               ;Initialize command field
  INC   R0                                      ;R0 => data field
  MOV   @R0,#SAMPLE_DATA_BYTE                   ;Initialize data field
LOOP3:
  MOV   DPL,MSG_PTR                             ;Send message to task 3
  MOV   DPH,#0
  CALL  RQSENDMESSAGE                           ;
  MOV   A,#MESSAGE_EVENT                        ;And wait for reply message
  MOV   B,#WAIT_FOREVER                         ;indefinitely
  CALL  RQWAIT                                  ;
  MOV   MSG_PTR,R7                              ;
  MOV   A,R7                                    ;
  ADD   A,#3                                    ;
  MOV   R0,A                                    ;R0 => FLAG FIELD
  MOV   @R0,#COMMAND_FLAG                       ;Change message back to command
  SJMP  LOOP3                                   ;and send it again

TASK_OF:
; Returns the task id for the specified function id, if there is one
; Inputs:  ACC = function id
; Outputs: ACC = task id OR 0ffh, if the function id is not found
;
  MOV   B,A                                     ;B = FID
  MOV   R1,#8                                   ;Initialize count
  MOV   DPTR,#RQFIDTABLE                        ;Initialize pointer
  MOV   R2,#0                                   ;Initialize index
TO_LOOP:
  MOVX  A,@DPTR                                 ;
  CJNE  A,B,TO_NO_MATCH                         ;If not match, jump
  MOV   A,R2                                    ;Load acc with task id
  RET                                           ;And return
TO_NO_MATCH:
  INC   DPTR                                    ;Increment pointers etc.
  INC   R2                                      ;
  DJNZ  R1,TO_LOOP                              ;
  MOV   A,#0FFH                                 ;If task id not found,
  RET                                           ;return with 0ffh

TASK4:
  CLR   RED_LED                                 ;
  MOV   MSG_COUNT,#0H                           ;Init. message counter
LOOP4:
  MOV   A,#MESSAGE_EVENT                        ;Wait for a command message
  MOV   B,#WAIT_FOREVER                         ;indefinitely
  CALL  RQWAIT                                  ;
  MOV   DPL,R7                                  ;
  MOV   DPH,#0                                  ;DPTR => command message
  MOV   A,R7                                    ;
  ADD   A,#3                                    ;
  MOV   R0,A                                    ;R0 => flag field
  MOV   A,@R0                                   ;A = flag contents
  ORL   A,#REPLY_FLAG                           ;Or-in reply flag bit
  MOV   @R0,A                                   ;Change message to reply and
  CALL  RQSENDMESSAGE                           ;Return message to sender
  DJNZ  MSG_COUNT,LOOP4                         ;Decrement message counter
  CPL   RED_LED                                 ;If zero, toggle red led
  SJMP  LOOP4                                   ;Loop

END