PR java/22084 [4.1 Regression] Divide_1 test case hangs

[Ranjit Mathew]

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Andrew Haley wrote:
> Ranjit Mathew writes:
>  >
>  > Andrew Haley wrote:
>  > > gcc at -O0 is now generating indexed loads for local variables via
>  > > register SP, rather than via BP as before.  This is confusing the
>  > > disassembler in Java's divide overflow handler, which had never seen
>  > > such loads before.  SP-indexed loads are 1 byte longer than BP-indexed
>  > > loads, so we need to increment PC.
>  > 
>  > Thanks a lot for looking into this and fixing it. This patch
>  > seems to fix PR java/22166 and I get a clean testsuite run
>  > once again. I don't know how you manage to figure out these
>  > things, but awesome.
> 
> Really, this one wasn't so very difficult.

Well, I spent a couple of really frustrating hours trying to
track this down and it doesn't look like that to me. :-/


> The most time-consuming part of the whole exercise was trying to find
> the page in the damned Pentium manual that describes the instruction
> encodings.  :-)

I thought I would never get to see anything about ModR/M
bytes again (I had written a simple disassembler for x86
around 10 years ago), not while working on GCJ at least.

Ranjit.

- --
Ranjit Mathew      Email: rmathew AT gmail DOT com

Bangalore, INDIA.    Web: http://ranjitmathew.hostingzero.com/


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