Re: [PATCH] Cleanup port 0x80 use (was: Re: IO delay ...)

[Martin Wilck]

On Sun, 17 Mar 2002, Jamie Lokier wrote:

> As long as __SLOW_DOWN_IO_PORT is a simple constant, you can just use
> this instead:
>
>     #define __SLOW_DOWN_IO_ASM	"\noutb %%al,$" #__SLOW_DOWN_IO_PORT

What cpp are you guys using? Mine does stringification (#s) only with
arguments of function-like macros. However

#define __SLOW_DOWN_IO_P(p) "\noutb %%al,%" #p
#define __SLOW_DOWN_IO __SLOW_DOWN_IO(__SLOW_DOWN_IO_PORT)

won't work, either, because cpp does not recursively substitute macros
for stringification, so in the above _SLOW_DOWN_IO wuold evaluate as
"\noutb %%al,$__SLOW_DOWN_IO_PORT" - bad.

I have tried a number of things to make this a single cpp line, but they
all don't work. The only way would be to change the way the inb_p ...
macros are coded.

It is possible to write
#define __SLOW_DOWN_IO __asm__ ("outb %%al, %0" : : "i" (__SLOW_DOWN_IO_PORT));

but only if one modifies the definitions of inb_p etc which are so complex
that I don't dare touch them now.

Please note that, as an intermediate solution, my patch reduces explicit
usage of the constant 0x80 from ~20 in 8 different source files to 2
immediately following each other in 1 source file.

Martin

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