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gcc linkage woes
- To: cygwin at cygwin dot com
- Subject: gcc linkage woes
- From: Greg Smith <gsmith at nc dot rr dot com>
- Date: 2001年2月06日 20:10:24 -0500
In a previous life (I beleive this was about 5 days ago ;-) Corrina
superbly answered some basic questions I had. We've moved on to a
new version of our software (http://www.conmicro.cx/hercules/) and
have encountered some weirdness on win32 under cygwin but not under
some other operating systems that may or may not begin with the
letter `l'. OK, so this is basically hobbyist software and people
aren't dying and nobody's losing money.
There is [at least] one routine that has a local stack size over 4K.
In the previous version, the beginning of the routine looked like:
routine entry
push %ebp
mov %esp,%ebp
mov 0ドルx303c,%eax
call 0x48af98 <_alloca>
push %edi
push %esi
push %ebx
r1 = parm1[3] >> 4;
mov 0x8(%ebp),%eax
add 0ドルx3,%eax
mov (%eax),%dl
shr 0ドルx4,%dl
Now the beginning of our routine is looking like:
routine entry:
mov 0ドルx303c,%eax
call 0x59b66c <_alloca>
push %ebp
push %edi
push %esi
push %ebx
mov %eax,0x303c(%esp,1)
mov %edx,0x3038(%esp,1)
mov %ecx,0x3034(%esp,1)
r1 = parm1[3] >> 4;
mov 0x303c(%esp,1),%eax
add 0ドルx3,%eax
mov (%eax),%dl
shr 0ドルx4,%dl
Well %eax, which has parm1, gets trashed, and we get garbage in our
variable `r1'!!
We can bypass the problem by making our local stack size less than 4K
and malloc() the storage we need.
Hints ?? (Yes!! I know!! I'm considering contributing!! perhaps in the
pthreads area... is cygwin in RTP ? just curious, 'cause I'm in the area)
Thanks, Greg
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