Difference between revisions of "Programming:Unlocking a protected basic file"
(Created page with 'You can protect a basic program by saving it with save"filename",p You can still '''run"''' a protected basic file, but can't '''load"''' and list it. There is a way to unlo…') |
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You can still '''run"''' a protected basic file, but can't '''load"''' and list it. | You can still '''run"''' a protected basic file, but can't '''load"''' and list it. | ||
| − | There is a way to unlock these basic files. This only works on a CPC 464 (real machine or emulator). | + | That is, after LOADing, the program is automatically deleted when returning to the BASIC prompt. Same applies when stopping a RUNning program via ESC key. |
| + | |||
| + | == CPC464 Workaround == | ||
| + | |||
| + | There is a way to unlock these basic files. This only works on a CPC 464 (real machine or emulator). The used addresses are 464-only (AC01h..AC02h=BASIC RAM, C064h..C090h=BASIC ROM). | ||
Type this: | Type this: | ||
| Line 17: | Line 21: | ||
Now you can '''list''' this program. | Now you can '''list''' this program. | ||
| + | |||
| + | == CPC664/6128 Workaround == | ||
| + | |||
| + | Below installs a resident Fast Ticker handler at BE00h. It resets the "protected file flag" once every 300Hz. | ||
| + | 10 FOR i=&BE00 TO &BE0F: READ a$: POKE i,VAL("&"+a$): NEXT | ||
| + | 20 CALL &BE00: NEW | ||
| + | 30 DATA 21,10,be,11,0b,be,06,81,c3,e0,bc,af,32,2c,ae,c9 | ||
| + | In the 664/6128/Plus, that flag is at AE2Ch. For the 464, it would need to be changed to AE45h, or, use the simplier POKE AC0Xh method on CPC464. | ||
Revision as of 07:21, 15 April 2010
You can protect a basic program by saving it with
save"filename",p
You can still run" a protected basic file, but can't load" and list it.
That is, after LOADing, the program is automatically deleted when returning to the BASIC prompt. Same applies when stopping a RUNning program via ESC key.
CPC464 Workaround
There is a way to unlock these basic files. This only works on a CPC 464 (real machine or emulator). The used addresses are 464-only (AC01h..AC02h=BASIC RAM, C064h..C090h=BASIC ROM).
Type this:
poke &ac02,&90 poke &ac03,&c0 poke &ac01,&c3
then load" the protected basic file. Done.
Now you can list this program.
CPC664/6128 Workaround
Below installs a resident Fast Ticker handler at BE00h. It resets the "protected file flag" once every 300Hz.
10 FOR i=&BE00 TO &BE0F: READ a$: POKE i,VAL("&"+a$): NEXT
20 CALL &BE00: NEW
30 DATA 21,10,be,11,0b,be,06,81,c3,e0,bc,af,32,2c,ae,c9
In the 664/6128/Plus, that flag is at AE2Ch. For the 464, it would need to be changed to AE45h, or, use the simplier POKE AC0Xh method on CPC464.
