Re: [Sdcc-user] Possible changes to inline assembler syntax

[Sebastien L. <seb...@lo...>]

Hi,

On 7/15/22 17:10, Maarten Brock wrote:
> Philipp Klaus Krause schreef op 2022-07-15 16:45:
>>>
>>>> Since people like form 1, I'd now think we should keep it, but drop
>>>> #pragma sdcc_hash. That looks like a better way forward and also
>>>> solves the issues.
>>>
>>> When this pragma is dropped does that mean it is no longer possible 
>>> to use the # for an immediate operand?
>>
>> You can still use a plain # (it already works now without using the 
>> pragma):
>>
>> void h(void)
>> {
>> __asm
>>     add    a, #3
>> __endasm;
>> }
>>
>>> Or will it be limited to use outside of a macro? I wouldn't even 
>>> know how to escape the #.
>>
>> The C standard requires "Each # preprocessing token in the replacement
>> list for a function-like macro shall be followed by a parameter as the
>> next preprocessing token in the replacement list." (see section
>> 6.10.3.2 of the current C2X standard N2912). Which makes sense, since
>> in the standard, # is meant for stringizing macro arguments. The
>> #pragma sdcc_hash is used to overide that.
>>
>> lib/ds400/ds400.rom.c currently has the following lines:
>>
>> // This macro is invalid for the standard C preprocessor, since it
>> // includes a hash character in the expansion, hence the SDCC specific
>> // pragma.
>> #pragma sdcc_hash +
>> #define ROMCALL(x) \
>>         mov     R6_B3, #(x & 0xff)              \
>>         mov     R7_B3, #((x >> 8) & 0xff)       \
>>         lcall   __romcall
>>
>> And then uses this macro from within __asm / __endasm. This will have
>> to be changed to e.g.:
>>
>> #define HASH #
>> #define ROMCALL(x) \
>>         mov     R6_B3, HASH(x & 0xff)              \
>>         mov     R7_B3, HASH((x >> 8) & 0xff)       \
>>         lcall   __romcall
>>
>> Philipp
>
> Ok, so the proper way to 'escape' the # inside a macro definition is 
> by using another macro.
> That is fine by me. We should probably put this in the manual even 
> though it is standard compliant.
>
> Maarten

I agree, it is very acceptable to change the literal hash into a nested 
macro.

Sebastien

>
>
> _______________________________________________
> Sdcc-user mailing list
> Sdc...@li...
> https://lists.sourceforge.net/lists/listinfo/sdcc-user