I wrote a decompiler for R83, never marketed it, just used it for my own play and insight.
-----Original Message----- From: Gyle Iverson <giver...@srs4uv.com> To: u2-users <u2-users@listserver.u2ug.org> Sent: Sat, Jan 5, 2013 12:29 pm Subject: Re: [U2] srs4uv.com status [Was: Corrupted object in global catalog] You are spot on Ian. It was a fun and tedious exercise. And you are right. The internals of each interpreter and its op codes are quite different. I wanted to answer the same question of how does one thing turn into another. And, can I reverse that? <history> The first decompiler was for Prime INFORMATION in 1982. There wasn't documentation available to me per se. However, looking through their compiled libraries you could glean the names of the op codes. Returning the statements and functions was straight forward. Recovering the logical structure of the program was the heavy lift. Way back then, what discussions I could find on logical structure recovery all said it was impossible. I discovered a way to take the distinct graph patterns associated with each compiled structure and reconstruct the original structure. That was a fun puzzle. Still today, most decompilers only return GOTO-filled source code. I always insisted on no-GOTOs (unless the original code was a pile of spaghetti originally) and there was no other way to reconstruct the program. The UniVerse decompiler came out in 1992. VMark was nice enough to leave a lot of useful information in some C language header files distributed with the product. I briefly looked at doing a UniData decompiler and never found sufficient time to dedicate to cracking that. Lee Leitner had a UniData decompiler on the market for a while. </history> -----Original Message----- From: u2-users-boun...@listserver.u2ug.org [mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of McGowan, Ian Sent: Friday, January 04, 2013 8:00 PM To: U2 Users List Subject: Re: [U2] srs4uv.com status [Was: Corrupted object in global catalog] Seems like a fun, if tedious, exercise in understanding the internals of compiled code. Surely different between ud and uv, given their lineage. Are there any tools or documentation available to give a head start? Does the debugger leak any information on the internals? It comes down to the question of how does: # cat IAN.TEST PRINT "HELLO" Turn into: # od -c _IAN.TEST 0000000 001 ? ÿ ÿ \0 p \0 001 \0 \0 \0 \0 \0 \0 \0 \0 0000020 \0 003 \0 001 \0 \0 \0 0 \0 \0 \0 \0 \0 \0 \0 0000040 / i n f o / D E V E L / B P . D 0000060 E V / I A N . T E S T \0 - 1 \0 H 0000100 E L L O \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000120 \0 004 \0 033 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 0000140 \0 005 \0 002 \0 \0 \0 034 ÿ ÿ ÿ ÿ \0 \0 \0 \0 0000160 \0 004 \0 005 \0 \0 \0 037 \0 \0 \0 \0 \0 \0 \0 \0 0000200 001 214 \0 001 \0 001 \0 005 \0 \0 \0 020 \0 001 \0 , 0000220 \0 001 \0 020 \0 002 \0 \0 \0 \0 \0 \0 \0 \0 \0 \0 -----Original Message----- From: u2-users-boun...@listserver.u2ug.org [mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of David Wolverton Sent: Friday, January 04, 2013 3:11 PM To: 'U2 Users List' Subject: Re: [U2] srs4uv.com status [Was: Corrupted object in global catalog] Question on the Source Code Recovery -- is the logic such that it could be 'open sourced' or GPL'd? Or is there another way to do the source recovery? That is, were the mechanics sold to Rocket Software Professional Services? If not, could they be sold to another company is someone wanted to keep the product active? While I don't have a need now, I like to think there is a place to go for 'the unthinkable' if it happened! Just wondering!! I don't know the circumstances that led to withdrawing this service -- I would think it would rarely be needed, but when it was, would be invaluable. Seems a loss if it's now got to be re-written from scratch!! -----Original Message----- From: u2-users-boun...@listserver.u2ug.org [mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Gyle Iverson Sent: Thursday, January 03, 2013 7:04 AM To: u2-users@listserver.u2ug.org Subject: [U2] srs4uv.com status [Was: Corrupted object in global catalog] Thanks for your comments David. I left http://srs4uv.com/ on-line for now. The hosting expires 2012/02/21 and the domain expires 2012/02/28. I added a Donate button to the main page in case people want to keep the site around and the links to it from breaking. Otherwise, the site vanishes next month. Gyle _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users ----------------------------------------- IMPORTANT NOTICE: This message is intended only for the addressee and may contain confidential, privileged information. If you are not the intended recipient, you may not use, copy or disclose any information contained in the message. If you have received this message in error, please notify the sender by reply e-mail and delete the message. _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users
