[Mjpeg-developer] jpeg-mmx problems

[William M. B. <wb...@mm...>]

I think I have found three problems in the sources of jpeg-mmx-0.1.6.  The
symptom was that software running without problems under libjpeg failed
(usually with a segfault) when using libjpeg-mmx, and Valgrind reported
illegal memory accesses.

1) jdcolor.c, at about line 265 - an extra 'pushl  %%ebx' (i.e. no matching popl)

2) jidctint.c, about line 1538, same problem

3) jdcolor.c, about line 350 - the instruction 'movq %%mm3,6%0' -
   This is a little more complicated.  If the output buffer is not a
   mutiple of 8 bytes, this instruction can "spill over" the allocated size.
   I have not come up with an appropriate fix - I just bypassed the problem
   by assuring my buffer was larger than needed.

Regards,

Bill