Xref: news2.mv.net comp.os.msdos.djgpp:6804
Newsgroups: comp.os.msdos.djgpp
From: joels AT twave DOT net (Joel Swanson)
Subject: Help reading the joystick port
Message-ID: <847cc$93634.13@nns>
Date: Sun, 04 Aug 1996 13:53:25 GMT
Reply-To: joels AT twave DOT net
Lines: 20
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

#define JOYPORT      0x201  // joyport is at 201 hex

asm volatile("
  xorl  %%eax , %%eax\n
  movl  %2  ,  %%es\n
  movw  %1  ,  %%edi\n
  movb  %%al  ,  %%es:(%%edi)\n
  movb  %%es:(%%edi)  ,  %%ah\n
  movw  %%ax  ,  %0\n

"  
: "=g"(Button_press)
: "g"(JOYPORT),"g"(_dos_ds)
: "ax","edi","memory"
  
); 

Could someone please explain to me why this fails to read the joystick port.  I am following several tutorials and all that 
I have read indicates that this should work.