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 Robotics / RCX / legOS / 639
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Subject: 
Re: RCX "locking up" when trying to use dll
Newsgroups: 
lugnet.robotics.rcx.legos
Date: 
Tue, 11 Jan 2000 22:04:20 GMT
Viewed: 
1536 times
  
In lugnet.robotics.rcx.legos, Ralph Hempel writes:
Ben Jackson wrote:

It's actually in the library.  I just found it.  Here is a disassembly of a
correct memcpy.o, as built by egcs-1.1.2:

<Snipped disassembly showing exactly what the bug is...>

What prompted you to look at memcpy? I'm curious because I like detective
stories related to embedded systems...

I built the H8/300 binutils-2.9.1 and gcc-2.95.2 and compiled the legOS kernel
and it was locking up when downloading programs.  People here said get
egcs-1.1.2 -- it works!  So I built egcs-1.1.2 and cd'd to legOS/boot, make
clean/make and the result still crashed.  If it wasn't the kernel it had to be
the libraries, so I cd'd to legOS/lib, rebuilt that, then relinked the kernel
and that worked.  The only interesting library is "libc" (the others are math
stubs).  I built it with both compilers, disassembled all of the objects and
started looking at diffs.  memcpy was actually first alphabetically so I found
it when I compared the first two .s files.

--Ben



Message has 1 Reply:
  RE: RCX "locking up" when trying to use dll
 
(...) Great story! When doing tedious diff compares, I usually find it in the last pair of files :-) Cheers, Ralph Hempel - P.Eng ---...--- The train stops at the train station, The bus stops at the bus station, So why am I sitting at a work (...) (25 years ago, 11-Jan-00, to lugnet.robotics.rcx.legos)

Message is in Reply To:
  RE: RCX "locking up" when trying to use dll
 
(...) <Snipped disassembly showing exactly what the bug is...> WOW! Good catch Ben! I have recently been looking through some disassembly on a totally unrelated topic and have found a bug in an unnamed commercial compiler. But of course I had a (...) (25 years ago, 11-Jan-00, to lugnet.robotics.rcx.legos)

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