Re: [Flashforth-devel] Fwd: Re: C function with more parameters in W0-W7

[Mikael N. <mik...@fl...>]

And to answer my own question.
It can be done like below


__attribute__((address(0x1000)))
float Ctest(unsigned short a, unsigned short b, unsigned long int c, 
float x, float y)
{
     a = a + 100;
     b = b / a;
     c = c * b;
     x = sqrtf( (float)c - x );
     y = y / x;
     return y;    // 4.5894021E-1
}


On 08.06.2015 23:03, Mikael Nordman wrote:
> How did you solve it ?
>
> In my tests you get this problem because the Ctest.c file is linked after
> the FF binary code into a the area where FF thinks is free space for the
> dictionary. Compiling some FF code will then overwrite the C code.
>
> This happens if you also include the float package into the compilation.
> If you do not include the float package, Ctest code will fit into memory
> before the FF binary code and all is fine.
>
> How can the linker be forced to link the C-code before the FF code ?
> Bu defining some new sections for the linker perhaps.
>
> There is no reason to save W0..W7 before calling the C function because
> these registers are not 'live' in FF between words.
>
> Mikael
>
> On 06.06.2015 19:30, om1zz wrote:
>> Solved, see examples.
>> I.
>>
>> _____________________________________________________________
>>>> Od: "om1zz" <om...@vo...>
>>>> Komu: Mikael Nordman <mik...@fl...>
>>>> Datum: 04.06.2015 19:00
>>>> Předmět: C function with more parameters in W0-W7
>>>>
>>>> MIke, I cope with following issue:
>>>>
>>>> I have a Cfunction, with 5 parameters, returning float.
>>>>
>>>> So I am using W0-W7 for params.
>>>>
>>>> The strange:
>>>> First time after the fresh flash the Cfun (when pasting the below
>>>> into teraterm) returns good result:
>>>>
>>>> decimal 100 2000 5. $0fdb $4049 $0fdb $4049 Ctest hex ok<#,ram> fa36
>>>> 3eea
>>>>
>>>> I can do it repeatedly, I always get good results.
>>>>
>>>> decimal 100 2000 5. $0fdb $4049 $0fdb $4049 Ctest hex ok<#,ram> fa36
>>>> 3eea
>>>> decimal 100 2000 5. $0fdb $4049 $0fdb $4049 Ctest hex ok<#,ram> fa36
>>>> 3eea fa36 3eea
>>>> decimal 100 2000 5. $0fdb $4049 $0fdb $4049 Ctest hex ok<#,ram> fa36
>>>> 3eea fa36 3eea fa36 3eea
>>>>
>>>> In the moment as I do something via prompt (before or after playing
>>>> with Cfun), the Cfun returns garbage (and also it corrupts the system).
>>>>
>>>> For example, I cannot get good results when after the fresh flash I do:
>>>> $0fdb $4049 2constant pi
>>>> decimal 100 2000 5. pi pi Ctest hex
>>>>
>>>> I've tried push/pop W4-W7, but the same.
>>>> I.
>>>>
>>>
>>>
>>>
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