prog16.asm

主要是8051源代码

;  PROG16 - Creating Variable Arrays
;
;  This Application Creates a Variable Array in the Scratchpad RAM and then
;   accesses it with reading and writing.
;
;  This program will run in the UMPS simulator for a DS80C320.
;
;  Myke Predko
;  98.02.17
;
;  Hardware Notes:
;   This program is only meant to run on the Simulator

;  Variable Declarations
;  R0 is used as an Index Pointer to Array
;  R1 is used as for temporary storage of Values when moving String Values

Array EQU 070h			;  Define Array in Scratchpad RAM

;  Mainline
 org 0                          ;  Execution Starts Here

  mov	 Array,#'H'		;  Initialize the Array to the 
  mov    Array+1,#'E'		;   ASCIIZ string "HEllo"
  mov	 Array+2,#'l'
  mov	 Array+3,#'l'
  mov	 Array+4,#'o'
  mov	 Array+5,#0		;  Terminate the String

;  Array[ 0 ] = Array[ 0 ] - 'A' + 'a'     //  Convert 'A' to Lower Case

  mov	 R0,#Array		;  Reset R0 to Point to the Start of the Array

  mov	 A,@R0			;  Get the Character
  clr	 C
  subb	 A,#'A'			;  Convert to Lower Case
  add	 A,#'a'
  mov	 @R0,A

;  Array[ 1 ] = Array[ 1 ] - 'A' + 'a'     //  Convert 'E' to Lower Case

  mov	 R0,#Array		;  Reset R0 to Point to the Start of the Array
  mov	 A,R0			;  Change Index to point to Second Character
  add	 A,#1
  mov	 R0,A

  mov	 A,@R0			;  Convert 'E' to Lower Case
  add	 A,#('a'-'A')		;  Calculate the Value Here
  mov	 @R0,A

;  Array[ 1 ] = Array[ 5 ]		//  Convert the String to Just "h"

  mov	 R0,#(Array+5)		;  Reset R0 to Point to the Start of the Array

  mov	 A,@R0			;  Get the character pointed to by the Index
  mov	 R1,A			;   And Save it for later

  mov	 R0,#Array		;  Reset R0 to Point to the Start of the Array
  inc	 R0			;  Jump to Index 1

  mov	 A,R1			;  Move the Contents of Array[ 5 ] to 
  mov	 @R0,A			;   Array[ 1 ]

Loop:                           ;  Loop Here Forever when Finished
  ajmp   Loop