collect.asm

来自「灭火控制盘（XMP4-2）」· 汇编 代码 · 共 30 行

$PAGEWIDTH (110)
$EJECT

  PUBLIC  C_RAM, C_EXTRAM
  COLLECT SEGMENT CODE
  RSEG    COLLECT
;**************************************
; funktion:  clear cpu ram
;**************************************
C_RAM:      MOV     PSW, #0
            MOV     7FH, #0
            MOV     R0, #7EH
CDAT:       MOV     @R0, 7FH
            DJNZ    R0, CDAT
            MOV     R0, 7FH
            RET
;**************************************
; funktion:  clear 62256
;**************************************
C_EXTRAM:   MOV     DPTR, #7FFFH
            CLR     A
          ; clear 7fffh-0100h
CXDA:       MOVX    @DPTR, A
            DJNZ    DPL, CXDA
            DJNZ    DPH, CXDA
          ; clear 00h-ffh
CXDA1:      MOVX    @DPTR, A
            DJNZ    DPL, CXDA1
            RET
END;