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From:	"Joel Saunders" <jbs30000 AT aol DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Simple extended inline assembly question.
Date:	Tue, 5 Feb 2002 14:55:29 +0000 (UTC)
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Ok, when learning inline assembly I did a test program which had these
variables:
char *Screen_PTR = (char *)(0xB8000 + __djgpp_conventional_base);
Which is a pointer to the text mode screen of course.
char My_Name[9] = {"J O E L "};
My name, obviously :)
Ok, now this routine works just fine.
__asm__(
        "cld\n\t"
        "movl $_My_Name, %esi\n\t"
        "movl _Screen_PTR, %edi\n\t"
        "movl $8, %ecx\n\t"
        "rep\n\t"
        "movsb"
);
But when I tried to make an extended inline assembly routine like so:
#define Mov_Byte(Src, Dest, Mov_Size)\
        __asm__ __volatile__(\
                "cld\n\t"\
                "rep\n\t"\
                "movsb"\
                : :"S" (Src), "D" (Dest), "c" (Mov_Size)\
                : "%esi", "%edi")
I can't get it to work.  The only thing I can use it, without generating
errors is to go:
Mov_Byte(My_Name[0], Screen_PTR[0], 8);
But nothing shows up on the screen.
Oh, and I don't include "%ecx" in the clobber list because then I get
the error:
Can't find a register in class `CREG' while reloading `asm'


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