On Wed, Apr 30, 2014 at 11:21:14AM -0400, Lennart Sorensen wrote:
> On Wed, Apr 30, 2014 at 07:53:30AM -0400, Lennart Sorensen wrote:
> > On Tue, Apr 29, 2014 at 04:47:26PM -0400, Lennart Sorensen wrote:
> > > It looks to me as if the problem might be here:
> > >
> > > sub rWORD1, r0101, rTMP2
> >
> > No that's not it. Still haven't figured it out.
>
> Does this actually fail with input like this:
>
> strcmp("", "bb")
>
> As far as i can tell that would return 0.
>
> I am seeing this (with my C version of the assembly code since I have
> no sparc to run it on):
>
> rWORD1: 0000000000000000 rWORD2: 6100000000000000
> aligned_loop_entry
> aligned_loop
> rTMP2: 00fefefefefefeff rSTRXOR: 6100000000000000 rTMP1: 8080808080808080
> common_endstring
> rTMP2: 0000000000000000 o1: 8080808080808081
> rTMP2: 7f7f7f7f7f7f7f7f
> rTMP1: 8080808080808080
> rTMP1: ff01010101010101
> Result: strcmptest("", "a") = 0
>
> rWORD1: 6100000000000000 rWORD2: 0000000000000000
> aligned_loop_entry
> aligned_loop
> rTMP2: 61fefefefefefeff rSTRXOR: 6100000000000000 rTMP1: 8080808080808080
> common_endstring
> rTMP2: 6100000000000000 o1: 8080808080808081
> rTMP2: e07f7f7f7f7f7f7f
> rTMP1: 0080808080808080
> rTMP1: 0001010101010101
> Result: strcmptest("a", "") = 1
>
> Clearly ending up with ff in the mask that was supposed to contain 00
> and 01 only is a problem.
OK, and I screwed up again. Must make sure to use unsigned long when
doing bit shift operations.
--
Len Sorensen
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