[avr-gcc-list] Re: cbr and negative numbers

[David Brown]

Ruud Vlaming wrote:
> Suppose you compile the (nonsense) code below under
> 'standard' settings (see below for my settings, but is does 
> not really matter for now) Then there is no problem. 
> However, if you activate the 8 bit integer option -mint8 
> you get an error:
>   code_Test.s:75: Error: number must be less than 256
>
>   void TestCBR(void) __attribute__ ((naked, used));
>   void TestCBR(void)
>   { asm volatile ( 
>      "cbr r31, 0xC0         \n\t" /* This value passes          */
>      "cbr r31,%[_A_]        \n\t" /* This value passes          */
>      "sbr r31,%[_B_]        \n\t" /* This value passes          */
>      "cbr r31,%[_B_]        \n\t" /* This may generate an error */
>      "ret                   \n\t" 
>      "" ::
>      [_A_] "i" (0x70),
>      [_B_] "i" (0xC0)); }

Have you tried using "M" as the constraint rather than "i" ?  I haven't 
tried this myself, but according to 
<http://www.nongnu.org/avr-libc/user-manual/inline_asm.html> "M" is an 
8-bit integer constant in the range 0 to 255.