'Commodore Assembler'
Author:J Achernar (registered user: 36 posts )
Date: Sat, Apr 09th, 2011 @ 23:00 ( . )

I have been taking a second look at my original of the Commodore Assembler Developer System. My original has a few be sectors. I have a good backup, but it was a file copy. It would be nice to have a clean image that preserves the exact sector layout of the files on the original.

I noticed on the original that there is a deleted file called “basictools”. I received the Assembler in used condition. The fellow that I bought my original 1541 from included it as part of the deal. I don’t know if the disk came this way from Commodore or if it was a file that he wrote to the original disk and later deleted.

Also, my original shows 536 blocks free. The deleted "basictools" file and two additional blocks are shown as used in the BAM.

If you have an image of the original for the Assembler, please take a look at it to see if it contains that deleted file. If it does, I would really appreciate it if you could post a hex dump of track 14 sectors 3 and 10.



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'Commodore Assembler'
Author:Pete Rittwage (registered user: 558 posts )
Date: Sun, Apr 10th, 2011 @ 21:11 ( . )

Here are the two I have archived. One is a perfect match to multiple disks, and the other has one block different- could just be a slightly bad read- let me know.

Neither have this extra file, so that may have been done accidentally through the ages on your disk.

(attached)

Attachments:
1302484298_cbmass.zip


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'Commodore Assembler'
Author:J Achernar (registered user: 36 posts )
Date: Sun, Apr 10th, 2011 @ 23:29 ( . )

Thanks Pete,

That proves that the fellow I bought my 1541 from, if memory serves at the end of 1983, wrote to his original. That is something I never did. I always kept originals pristine.

I compared the two versions that you posted. The only difference is that the (!) version has an A6 at track 17 sector 4 byte 84 and the (alt) version has an A5. This corresponds to block 3 of “editor64”. My original has an A5 and this block appears to be clean. I also looked at a copy that I had downloaded from the net for comparison purposes. This one was just a file copy with an added turbo loader. Block 3 of editor 64 also contains an A5 in that position. I haven’t tried to disassemble “editor64” yet.

I didn’t see any other differences in used blocks of yours compared to my repaired (using my backup) original other than the additional file.



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'Commodore Assembler'
Author:Pete Rittwage (registered user: 558 posts )
Date: Mon, Apr 11th, 2011 @ 08:30 ( . )

A single-bit difference smells of corruption. Strange that yours and others verify to my alt-version. I wonder what this bit affects...


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'Commodore Assembler'
Author:J Achernar (registered user: 36 posts )
Date: Tue, Apr 12th, 2011 @ 20:23 ( . )

I think that it was more likely a bug fix. It is not likely a GCR error as A5 converts to GCR 11010 01111 and A6 converts to 11010 10110.

I believe that my original is a very early copy. The disk and original manual look very different than the scan that is available on bombjack.org. E.g. there is no part number on the disk.

Disassembling my version with the A5 at C27B,
.C:c268 84 B7 STY $B7
.C:c26a 20 79 00 JSR $0079
.C:c26d F0 03 BEQ $C272
.C:c26f 20 0E E2 JSR $E20E
.C:c272 20 52 C4 JSR $C452
.C:c275 20 E6 E1 JSR $E1E6
.C:c278 A9 08 LDA #$08
.C:c27a A8 TAY
.C:c27b A5 BA LDA $BA
.C:c27d 20 BA FF JSR $FFBA
.C:c280 A5 B7 LDA $B7
.C:c282 A6 2D LDX $2D
.C:c284 A4 2E LDY $2E
.C:c286 20 BD FF JSR $FFBD
.C:c289 20 C0 FF JSR $FFC0
.C:c28c A5 90 LDA $90
.C:c28e F0 07 BEQ $C297
.C:c290 C9 40 CMP #$40
.C:c292 F0 03 BEQ $C297
.C:c294 4C 94 C5 JMP $C594
.C:c297 A2 08 LDX #$08
.C:c299 60 RTS

Changing C27B to an A6 it becomes,
.C:c27b A6 BA LDX $BA
which provides the third argument to the SETLFS routine.

I have not verified this by a detailed run time test yet, and it may be a little time before I do. In the little bit that I have used it, both back in the day and recently, I thought that the editor worked correctly as far as loading and saving files.


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'Commodore Assembler'
Author:J Achernar (registered user: 36 posts )
Date: Tue, Apr 12th, 2011 @ 20:47 ( . )

I forgot to mention that my April 10 post had an error. That should have been byte 83 not byte 84.


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