in sparc linux system call entry assembly code

[Valdis.Kletnieks at vt.edu]

On Fri, 28 Mar 2014 07:25:37 -0000, 김찬 said:
>         andcc   %l7, 1, %g0
>         bne     linux_fast_syscall

> Then what is this "andcc %l7, 1, %g0" doing?

Well, I'm not an expert on Sparc assembler, but.. 'andcc' looks like it's
doing an and, and setting the cc (condition code).  Then 'bne' branch not
equal.  Looks to me like it's testing a bit in the just-loaded address
to see if it's flagged as using the fast_syscall code.  Go check the code
that generates the table and see if there is something different about the
way they generate some entries.
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