[DPRG] Off Topic: gcc help
Subject: [DPRG] Off Topic: gcc help
From: Stuart Stegall
keltor at keltor.org
Date: Wed Jul 21 10:40:50 CDT 2010
Do a lot of integer math to test it. Then see if you can read and
write to various IO ports.
You'll of course have to load the executables to the new processor (or
the simulator)
On Wed, Jul 21, 2010 at 7:34 AM, <warm38 at juno.com> wrote:
> I have been informed that there is indeed a very small library that does
> contains those "basic" functions but that there is no "math" library for
> float double long sin() cos() log() etc.
>
> So I have to come up with something to "prove" that the "basic"
> functionality works (with char and 16bit int).
>
> The + and  stuff is easy using "special" values. I'm wondering about
> multiply and divide.
> Max signed char is 127 which is useful for divide, but too big for
> multiply. The max number for multiply would be 11 (11*11=121; 12*12=144,
> so stay low) unless I want to test overflow. Hmmm ... how DO you test
> overflow when multiplying, adding or subtracting? With integer values
> there isn't an overflow condition with divide (zero is illegal) because
> the numbers just get closer to 1.
> Zero is OK for testing multiply and divide, just not as a denominator.
> 1, 2, 3, 5,7, 11 sould like good numbers for multiply and divide.
>
> Puzzle: Can you think of any shortcuts, like one or two equations that
> will verify a few of the basic math functions and come up with a good
> number if it all works and give garbage is if doesn't go smoothly?
>
>
>
> On Tue, 20 Jul 2010 14:13:18 0700 Dave Hylands <dhylands at gmail.com>
> writes:
>> Hi guys,
>>
>> > 11. Operators:
>> > (a) Arithmetic (+, , *, /, %)
>> > This will be where the work needs to be done.
>> > 1) no math library
>> > 2) no available multiply nor divide instruction,
>> so a
>> > library is needed for those functions
>> > 3) no divide, so '%' will require a "library"
>> function
>>
>> My understanding is that this is the purpose of libgcc.a is for 
>> it
>> provides helper functions to perform those operations that C
>> requires,
>> but which the microprocessor can't implement directly.
>>
>> 
>> Dave Hylands
>> Shuswap, BC, Canada
>> http://www.DaveHylands.com/
>>
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