Re: [Flashforth-devel] Floating point library - open issues

[om1zz <om...@vo...>]

4. Stack(s) issue?

When running following test (math functions calculations in a simple loop):

https://github.com/igor-m/EXPERIMENTAL_ZZ/blob/master/examples/Big%20Torture%20Test%20NO%20NANS%20and%20BIG%20_POS_NEG.txt

it locks (with "rtc time" clock running or not (inerrupt not init), with do-loop or for-next loop as the main test loop).

With default settings: 
data stack = 96
return stack = 96
min XC16 stack = 128
with dspic33 and pic24 chips, FF - 17.5.2015,
@27MHz

it usually locks near the end of the first loop.

With settings like:

data stack = 180
return stack = 180
min XC16 stack = 128
with dspic33 and pic24 chips, with FF - 17.5.2015,
@27MHz

it locks after a longer time and ~dozens/hundreds of loops,

With 

data stack = 254
return stack = 254
min XC16 stack = 128
with dspic33 and pic24 chips, with FF - 17.5.2015,
@27MHz 

it passes the test (it runs for about 8 minutes).

With default 96 settings it restarts with OS after the crash, with 180 settings with W.

When doing the specific calculations (at which it crashes) from the prompt, I get correct results and I see no issues.
I think it should work with the 96 default, as the calculation within the test are single line, simple primitive 
calculations without any loops, nestings or recursions.
It seems there is a subtile issue somewhere, I cannot find the cause however.

Igor



______________________________________________________________
> Od: "om1zz" <om...@vo...>
> Komu: "flashforth-devel" <fla...@li...>
> Datum: 30.05.2015 10:53
> Předmět: Floating point library - open issues
>
>Hi,
>as discussed with Mike before, there are few open issues with floating point library, which are not critical, but needs some tweaking to be perfect, however.
>
>1. handling largest positive and largest negative number, it crashes now.
>2. printing NaN, crashes
>3. "e" for exponent
>
>1. 
>
>0x7f7fffff == 3.402823466385288598E38
>0xff7fffff ==  -3.402823466385288598E38
>
>does
>
>$ffff $7f7f fs.  - crash
>$ff7f $ffff fs. - crash
>
>2. 
>
>-1.0e3 flog fs. crash
>-1.0e3 fsqrt fs. crash
>$ffff $7fff fs. crash
>$ffff $ffff fs. crash
>
>Those calcs shall print something like "NaN"
>
>The bove issues come from following - the floating point library was written for amorth, and the math written in asm returned specific agreed values for those results. XC16 returns different values in FF.
>
>3.
>
>Mainly an issue with 0e 3e 123e as it could be recognised as HEX value when in hex. "E" may solve the problem, when agreed so.
>
>Igor
>