From:	Ben Peddell <killer DOT lightspeed AT bigpond DOT com>
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Inline assembly error
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Date:	Sun, 10 Aug 2003 05:48:45 GMT
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To:	djgpp AT delorie DOT com
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Joel wrote:
> One of the SVGA graphics routines I'm making has given me an inline
> error message.
> What I'm doing is making a routine to call the protected mode verson
> of
> Function 9 -Set/Get Palette Data
> BL = 0 - Set Palette Data / 80H Set Palette Data During Vertical
> Retrace
> CX = Number of Palette Registers to Update
> DX = First of the Palette Registers to Update
> ES:EDI = Table of Palette Values
> So, here's my routine
> unsigned short PM_Palette_Data(unsigned char Flag, unsigned short
> PCount, unsigned short FirstPal, unsigned short TableSeg, unsigned
> long TableOff)
> {
>         asm("movw %%ax, %%es\n\t"
>             "call *%0"
>             :
>             : "r" (PMPaletteData),

OK. This code is to call PMPaletteData.

 >               "b" (Flag),

OK. ebx is to be Flag.

 >               "C" (PCount),

There is no "C" constraint on the i386.
Try the "c" constraint.

 >               "a" (TableSeg),

OK. eax is to be TableSeg.
You need to save and restore es.

 >               "D" (TableOff)

OK. edi is to be TableOff.

Where's FirstPal?

>         );
> }
> 
> And here's the error I get
> Error: inconsistent operand constraints in an `asm'
> Referring of course, to the "movw %%ax, %%es\n\t"
> I'm not sure why this is happening.  movw is move word ax and es are
> words, although maybe it's confusing es as esi, but then what would I
> use to represent ES?
> Anyway, I'm still getting use to AT&T style DJGPP extended inline
> assembly, so any help is appreciated.  Thanks.

Perhaps:

unsigned short
PM_Palette_Data (unsigned char Flag, unsigned short PCount,
                  unsigned short FirstPal, unsigned short TableSeg,
                  unsigned long TableOff){
     int retval;
     asm (
          "pushl %%es\n\t"
          "movw %w0, %%es\n\t"
          "call *%1\n\t"
          "popl %%es"
          : "a" (RetVal)
          : "r" (TableSeg), "r" (PMPaletteData),
            "b" (Flag), "c" (PCount), "d" (FirstPal), "D" (TableOff)
     );
     return retval;
}

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