A small memory editor for checking and changing machine code. Add it to the end of a program and GOTO 9500, or RUN it on its own. Give a starting address, and the program shows the address and its contents. Type a new value of up to three digits to POKE it (ENTER after fewer than three), ENTER to leave it alone, or / to go back to the previous address. Because it reads keys with INKEY$, use it in SLOW mode. BREAK stops it.
The second listing replaces three lines to show and enter the bytes as two-digit hex numbers. The download has both versions.
Published in Syntax December 1983 (Examining Machine Code).
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Source Code
9500 PRINT "ADDRESS"
9510 INPUT ADR
9515 SCROLL
9520 PRINT ADR;" ";PEEK ADR;" ";
9525 LET NEW=0
9530 FOR I=1 TO 3
9535 IF INKEY$<>"" THEN GOTO 9535
9536 IF INKEY$="" THEN GOTO 9536
9540 LET X$=INKEY$
9550 IF X$=CHR$ 118 AND I=1 THEN GOTO 9610
9560 IF X$=CHR$ 118 THEN GOTO 9600
9565 IF X$="/" THEN GOTO 9640
9566 PRINT X$;
9570 LET NEW=NEW*10+VAL X$
9580 NEXT I
9600 POKE ADR,NEW
9610 SCROLL
9620 LET ADR=ADR+1
9630 GOTO 9520
9640 SCROLL
9650 LET ADR=ADR-1
9960 GOTO 9520
9520 PRINT ADR;" ";CHR$ (INT ((PEEK ADR)/16+28));CHR$ ((PEEK ADR)-16*INT ((PEEK ADR)/16)+28);" -";
9530 FOR I=1 TO 2
9570 LET NEW=NEW*16+CODE X$-28Note: Type-in program listings on this website use ZMAKEBAS notation for graphics characters.