[tremor] Compiling on platforms without 64-bit integer support

Tom Lukasiak tlukasiak at yahoo.com
Fri Sep 13 18:47:19 PDT 2002



--- Ramakrishnan M <gnu at vsnl.net> wrote:
>  || On Wed, 11 Sep 2002 09:36:34 -0700 (PDT)
>  || Tom Lukasiak <tlukasiak at yahoo.com> wrote: 
> 
>  tl> I saw this issue in a previous post, but I
> still have some more questions about it.  My DSP
> platform is dual 16-bit ALU
> 
> What exactly is your DSP ?
> 

I'm working with an Analog Devices Blackfin DSP.

>  tl> Also, I think I will probably use a
> Windows-based IDE for the development.  Could I
> trust that some architecture-specific
>  tl> files, like os.h, os_types.h will for the most
> part remain unchanged throughout development?  I
> would suppose that a lot
>  tl> of the current development is focused on the
> decoding algorithm.  Having set up the
> machine-specific files once, it would
> 
> YOu can always encapsulate your code additions with
> your particular compiler name 
> or architecture name.
> 

Right, but I still have a problem.  As is, the Tremor
implementation uses algebraic syntax (+, -, *,
etc.)for 64-bit integers.  The problem is that not all
processors support 64-bit arithmetic.  Whether they
all should, I don't know, but we've seen compilers for
at least two CPUs that don't.  Now, implementing
64-bit math is not that hard, but having to replace
algebraic operations with calls to custom arithmetic
functions is a pain -- you have to track each 64-bit
variable and replace builtin ops with function calls. 
So maybe 64-bit math should be treated as a special
case, just as 32x32 bit multiplication is (MULT31,
etc.)  Maybe I can operator overload using the C++
compiler.

> -- 
>     Ramakrishnan M         (http://www.hackGNU.org/)
>     Use Free Software          (http://www.gnu.org/)
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