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DDTPATCH.ASM
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Assembly Source File
|
1984-04-29
|
1KB
|
85 lines
;PATCHES TO FIX DDT.COM VERSION 1.3 BY JEFF ZURKOW
;
;(AS DESCRIBED TO A.R.G. BY TELEPHONE)
;
;THIS ONE IS DIFFERENT - IT WORKS.
;
;TO USE:
; 1) "DDT DDT.COM" LOAD DDT.COM UNDER DDT
; 2) "IPATCH.HEX" INSERT PATCH -
; 3) "R0" - WHERE IT IS ORGED
; 4) "G1700" RUN THE PATCH (SUCH ELEGANCE)
; 5) "SAVE 19 DDTX.COM" AND SAVE THE PATCHED COPY
;
;TRY OUT DDTX ON THE CONDITIONALS AND OTHER INSTRUCTIONS.
;IF IT'S OK, REPLACE THE ORIGINAL WITH THIS.
;COMES UP WITH VER 1.3X MESSAGE TO IDENTIFY PATCHED VERSIONS
;
;EQUATES
BOOT EQU 0
BDOS EQU 5
DDT EQU 38H
;
ORG 100H
LXI B,1004H
;
ORG 137H
DB ' 1.3X' ;CHANGE MESSAGE
;
ORG 14FH
NOP
ORG 13A5H
DB 4,90H
;
ORG 1700H
I
LXI SP,STACK
LXI H,13A6H
LXI D,1404H
LXI B,201H
LOOP: MOV A,M
STAX D
DCX H
DCX D
DCX B
MOV A,B
ORA C
JNZ LOOP
LXI H,4CEH
MVI M,0C3H
INX H
MVI M,0FBH
INX H
MVI M,0FH
;
LXI H,11FBH
MVI M,0CDH
INX H
MVI M,55H
INX H
MVI M,1
INX H
MVI M,0CDH
INX H
MVI M,0CBH
INX H
MVI M,0
INX H
MVI M,0C3H
INX H
MVI M,0D1H
INX H
MVI M,02H
;
;NOW BACK TO CP/M FOR BOOT
LXI D,MSG
MVI C,9
CALL BDOS
JMP BOOT
;
MSG: DB 'TYPE "SAVE 19 DDTX.COM TO SAVE PATCHES"$'
;
ORG $+20
STACK: