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- ;==RDDTMOD.ASM===H WEINSTEIN=== 8303200530 =================
- ;
- ; DDT is a trademark of Digital Research,Inc. DDT.COM is a
- ; copyright program of Digital Research, Inc. Do not distri-
- ; bute modified copies of DDT.COM. Do not exceed the
- ; ridiculous limitations of your license agreement with
- ; Digital Research, Inc.
- ;
- ;\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
- ;\\ Copyright 1983 H Weinstein, San Diego CA 92128. \\
- ;\\ All rights reserved. May be copied for \\
- ;\\ personal, non-commercial use only. \\
- ;\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
- ;
- ; The following is for personal experimentation purposes only.
- ;
- ; This is a modification of DDT.COM version 2.2 which
- ; permits the operator to determine where DDT will run
- ; between the limits of 1500h and (BDOS and 00FFh)-1000h.
- ;
- ; This helps to keep DDT out of the way of something you
- ; might want to look at (e.g., CCP) which would not be
- ; possible under standard DDT.
- ;
- ; - - - - - - - - - - - - - - - - - - - -
- ;
- ; RECIPE:
- ;
- ; 1. Change the name of this file to RDDTMOD.ASM
- ; 2. Assemble it to obtain a file named RDDTMOD.HEX
- ; 3. Place the disk with this hex file in drive A:
- ; 4. If DDT is on the same disk, go to step 5 else
- ; mount the disk with DDT in drive B:
- ; 5. Invoke DDT
- ; 6. Enter the following series of commands after
- ; receiving the DDT prompt. For the purpose of
- ; this recipe, DDT's messages are in square
- ; brackets. You enter the commands which are NOT
- ; so enclosed, following each with a RETURN or
- ; ENTER keystroke. Here is the series:
- ;
- ; [-] F100,2000,0
- ; [-] IDDT.COM
- ;
- ; NOTE WELL: If your DDT disk is in drive B: then enter the
- ; following, else skip to the line following
- ; NOTE 2.
- ;
- ; [-] S5C
- ; [005C 00] 2
- ; [005D 44] .
- ;
- ; NOTE 2: See above
- ; [-] R
- ; [NEXT PC]
- ; [1500 0000]
- ; [-] G0
- ;
- ; A>SAVE 20 RDDT.COM
- ;
- ; When the system prompt appears on the screen, RDDT is
- ; available for your experimental use. It is self-
- ; prompting. All you will need to remember is that
- ; when you respond with, say, page A6, the TPA from
- ; 0A600h through 0B5FFh will be in use by the program.
- ;
- ; - - - - - - - - - - - - - - - - - - - -
- ;
- org 12Dh
- db 13,10,'R'
- org 143h
- db 2Dh
- ;
- org 14Bh
- jmp 1400h
- ;
- org 1400h
- push b
- lda 7
- sui 10h
- push psw
- mov h,a
- rrc ! rrc ! rrc ! rrc
- call bcd2asc
- sta max
- mov a,h
- call bcd2asc
- sta max+1
- call max$msg
- db 13,10,10
- db 'Enter HEX page number:',13,10,9
- db 'NOT less than 15h nor more than '
- max db 'XXh.',13,10,10
- db '<CR> gives maximum default. SELECTION: $'
- bcd2asc ani 0Fh
- adi 90h
- daa
- aci 40h
- daa
- ret
- accept mov b,a
- cpi 0Ah
- mvi a,0
- rc
- mov a,b
- cpi 11h
- mvi a,0FFh
- rc
- mov a,b
- sui 7
- mov b,a
- cpi 10h
- mvi a,0
- rc
- mvi a,0FFh
- ret
- max$msg mvi c,9
- pop d
- call 5
- mvi c,1
- call 5
- cpi 13
- jz default
- sui 30h
- call accept
- ora a
- jnz 100h
- mov a,b
- sta max
- mvi c,1
- call 5
- sui 30h
- call accept
- ora a
- jnz 100h
- mov a,b
- sta max+1
- lda max
- add a ! add a ! add a ! add a
- lxi h,max+1
- add m
- mov b,a
- cpi 15h
- jc 100h
- pop psw
- cmp b
- jc 100h
- mov a,b
- pop b
- jmp 151h
- ;
- default pop psw
- pop b
- jmp 151h
- end