Date: Sat, 20 Nov 2010 17:29:48 -0500 From: Jack Ferris <jhferris3@gmail.com> To: freebsd-tilera@freebsd.org Subject: Project Status Report Message-ID: <AANLkTint%2BHAjhj8PZch1iv7nb2zrZ0s8oH2d-ewZaQdV@mail.gmail.com>
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Matt Schnall and I have spent the last few months working on this
port. Progress has been a bit slow as this is the first time either of
us has handled FreeBSD source/build infrastructure. Our goal is to get
up to userland in some form by the end of our class (Dec ~10). We've
made progress on porting over the virtual memory system, as well as
implementing a crude version of atomic operations (more on this in a
future message).
So far, we've made it up into mi_startup and have the copyright
message printing out.
We're currently blocked on getting a few math functions to work
(__umodsi3, __divsi3, etc). Its my understanding that these are
normally provided by libgcc.a , but we've had trouble getting that
built under the tile toolchain. Instead, I was trying to get these
functions by writing c-versions, such as:
unsigned int __umodsi3(unsigned int a, unsigned int b)
{
return a%b;
}
which compiles down to:
000108b8 <__umodsi3>:
108b8: dfdd08006b7a5000 { sw sp, lr }
108c0: 0833fe8ef0165000 { move r29, r52 }
108c8: 0833feda70165000 { move r52, sp }
108d0: 301f66ce70165000 { addi r28, sp, -20 }
108d8: 301f46db70165000 { addi sp, sp, -24 }
108e0: df7508006b4a5000 { sw r28, r52 }
108e8: 301fe68df0165000 { addi r27, r52, -4 }
108f0: 0833fb6d70165000 { move r26, r27 }
108f8: df6d080069da5000 { sw r26, r29 }
10900: 301fa68170165000 { addi r2, r52, -12 }
10908: df0d0800680a5000 { sw r2, r0 }
10910: 301f868070165000 { addi r0, r52, -16 }
10918: df050800681a5000 { sw r0, r1 }
10920: 301fa68070165000 { addi r0, r52, -12 }
10928: 301f8680f0165000 { addi r1, r52, -16 }
10930: dc050800680a5000 { lw r0, r0 }
10938: dc0508006c1a5000 { lw r1, r1 }
*** 10940: 6fff7ffff0165000 { jal 108b8 <__umodsi3> }
10948: dcd508006b7a5000 { lw lr, r52 }
10950: 301fe68e70165000 { addi r28, r52, -4 }
10958: dc75080069da5000 { lw r29, r28 }
10960: 0833fe9b70165000 { move sp, r52 }
10968: 0833fbba70165000 { move r52, r29 }
10970: 081606e070165000 { jrp lr }
Now, I can't speak for the rest of this dis-assembly, but if you look
at the instruction I starred, it *always* jumps back to the start of
the function, and there aren't any conditionals/branches that I can
see. This would lead me to believe this generated code is
broken/incorrect. Unfortunately we need some working version of these
to proceed. Does anyone have a tile version of libgcc.a? or have an
alternative solution? If more information/context is needed, we'll try
and do our best.
-Jack
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