From: "Ken Jenkins" <ken DOT jen AT adelphia DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Problems adressing memory variable
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Date: Fri, 14 Mar 2003 07:54:25 GMT
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

This program is supposed to print "Hello!" in gray letters on a blue
background at screen position (10, 10).  However all I'm getting is the blue
background with no text, 6 characters long.  Can anybody tell me what I'm
doing wrong?

void display_string (unsigned short int x, unsigned short int y, unsigned
short int text_color, unsigned short int bg_color)
{

        unsigned short int column = (x - 1);

        unsigned short int row = (y - 1);

        char * disp_str = "Hello!";

        unsigned short int length = 6;

        asm
 (

                "movw $0x1301, %%ax\n\t"

                "movb $0x00, %%bh\n\t"

                "shlb $0x04, %1\n\t"

                "movb %0, %%bl\n\t"

                "addb %1, %%bl\n\t"

                "movw %2, %%cx\n\t"

                "movb %3, %%dl\n\t"

                "movb %4, %%dh\n\t"

                "movl %5, %%ebp\n\t"

                "int $0x10"

  :

                : "g" (text_color), "g" (bg_color), "g" (length), "g"
(column), "g" (row), "o" (& disp_str[0])

                : "%ax", "%bx", "%cx", "%dx", "%ebp"

 );

};

int main (void)
{

        display_string (10, 10, 7, 1);

 return 0;

};