;
;       THIS LITTLE UTILITY ZEROS OUT A 64K BLOCK OF MEMORY
;
;       JUST SAY
;
;               ZERORAM N
;
;       WHERE N IS 0-9 OR A-F
;

                ORG 0100
ZERORAM:        JMP > L0
MSG             DB      CR,LF,'Block '
ID              DB      0,'000 is zeroed out',CR,LF,'$'
ERMSG           DB      CR,LF,'No address given...Aborting',CR,LF,'$'
ERMSG1          DB      CR,LF,'Bad address range...Aborting',CR,LF,'$'
L0:             MOV AH,[080]
                CMP AH,1
                JA > L1
                PRINT ERMSG             ;STANDARD MACRO
                QUIT 0
L1:             MOV SI,081
L2:             MOV AH,[SI]
                INC SI
                CMP AH,SPACE
                JE L2
                MAKE_CAP AH             ;STANDARD MACRO
                MOV B ID,AH
                SUB AH,030
                CMP AH,9
                JBE > L3
                SUB AH,7
                CMP AH,0F
                JBE > L3
                PRINT ERMSG1            ;STANDARD MACRO
                QUIT 0
L3:             MOV CX,4
                ROR AH,CL
                AND AX,0F000
                MOV ES,AX
                MOV CX,0
                XOR SI,SI
L4:     ES      MOV B[SI],0
                INC SI
                LOOP L4
                PRINT MSG               ;STANDARD MACRO
                QUIT 0
                END