Third time's the charm? It's been so long since I've dealt with K&R C I've
forgotten the rules.
The behavior is correct. char and short are upcast to int when no
declaration is in scope. Integral types that are larger than int are left
as is. That you're masking off all but the low byte does not change the
type of the expression that's used as a parameter: it's a 32-bit int on a
16-bit microcontroller, and requires two registers to pass by value.
No bug here. Either explicitly cast to int, or make sure there's a
declaration in scope so the compiler knows what to do. I suggest the
latter.
Peter
On Thu, Oct 7, 2010 at 7:26 AM, Kim Toms <kim.t...@gmail.com> wrote:
> I had a function which took a byte argument and returned a byte. From
> another file (compiled into a separate object), I called the function
> without first declaring it. The calling function used an argument which
> evaluated to uint32_t.
>
> In the called function, it looked for the argument in R15. In the calling
> function, it left the low byte of the argument in R14.
>
> Declaring the called function fixed the problem. Here's an example:
>
> file1.c:
> uint8_t bytefunc(uint8_t arg)
> { ...
> }
>
> file2.c:
> extern uint8_t bytefunc(uint8_t); // this line required to make the ABI
> generate the correct code
>
> main()
> {
> uint32_t i = 123456;
> bytefunc(i & 0xFFL);
> }
>
>
> ------------------------------------------------------------------------------
> Beautiful is writing same markup. Internet Explorer 9 supports
> standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3.
> Spend less time writing and rewriting code and more time creating great
> experiences on the web. Be a part of the beta today.
> http://p.sf.net/sfu/beautyoftheweb
> _______________________________________________
> Mspgcc-users mailing list
> Mspgcc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/mspgcc-users
>
>
------------------------------------------------------------------------------
Beautiful is writing same markup. Internet Explorer 9 supports
standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3.
Spend less time writing and rewriting code and more time creating great
experiences on the web. Be a part of the beta today.
http://p.sf.net/sfu/beautyoftheweb
_______________________________________________
Mspgcc-users mailing list
Mspgcc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/mspgcc-users
