Fillmem.asm

Functions Provided

Entry point	Function provided	Notes
FILLMEM	Fill a block of memory with a value	Destination, value and length passed in registers.
FILLZERO	Fill a block of memory with zeros	Destination and length passed in registers. Fills with zero.
CLRSCR	Clear the screen.	Fills BACKTAB with zeros.

See source code below for calling convention.

Examples

(todo... please contribute!)

Source Code

;* ======================================================================== *;
;*  These routines are placed into the public domain by their author.  All  *;
;*  copyright rights are hereby relinquished on the routines and data in    *;
;*  this file.  -- Joseph Zbiciak, 2008                                     *;
;* ======================================================================== *;

;; ======================================================================== ;;
;;  FILLZERO                                                                ;;
;;      Fills memory with zeros                                             ;;
;;                                                                          ;;
;;  FILLMEM                                                                 ;;
;;      Fills memory with a constant                                        ;;
;;                                                                          ;;
;;  INPUTS:                                                                 ;;
;;      R0 -- Fill value (FILLMEM only)                                     ;;
;;      R1 -- Number of words to fill                                       ;;
;;      R4 -- Start of fill area                                            ;;
;;      R5 -- Return address                                                ;;
;;                                                                          ;;
;;  OUTPUTS:                                                                ;;
;;      R0 -- Zeroed if FILLZERO, otherwise untouched.                      ;;
;;      R1 -- Zeroed                                                        ;;
;;      R4 -- Points to word after fill area                                ;;
;; ======================================================================== ;;
CLRSCR      PROC
            MVII    #$0F0,  R1
            MVII    #$200,  R4
FILLZERO    CLRR    R0              ; Start out with R0 zeroed for FILLZERO
FILLMEM     MVO@    R0,     R4      ; Store R0 out at R4, and move along
            DECR    R1              ; Keep going until our count runs out
            BNEQ    FILLMEM
            JR      R5              ; Return to the caller.
            ENDP

;; ======================================================================== ;;
;;  End of File:  fillzero.asm                                              ;;
;; ======================================================================== ;;