Message-ID:	<38DFBF98.8BEB44EB@corel.com>
Date:	Mon, 27 Mar 2000 15:07:52 -0500
From:	Jonathan Meunier <jonathanm AT corel DOT com>
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Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: keyboard interrupt
References:	<8bod7h$rj1$1 AT gxsn DOT com>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

Here's the one I use.. This is by no means a tutorial, simply cuz it's
not commented :)  but if you need a good tutor, try PCGPE (PC Game
Programming Encyclopedia).. http://www.qzx.com/pc-gpe/keyboard.txt


---[keyboard.cpp]---
#include "keyboard.h"  // all #defines for keys (ie: #define ESC 1

extern bool quit_prog;

bool kb_installed = FALSE;
bool keyboard[256];  // all possible characters
_go32_dpmi_seginfo old_kb_seginfo, new_kb_seginfo;

void new_keyboard_int() {
  unsigned char keyscan;

  keyscan = inportb(0x60);
  keyboard[keyscan] = TRUE;
  if(keyscan > 0x80)
    keyboard[keyscan - 0x80] = TRUE;
  outportb(0x20,0x20);  // acknowledge interrupt
}

void install_keyboard() {
  if(kb_installed == TRUE)
    return;

  new_kb_seginfo.pm_offset = (int)new_keyboard_int;
  new_kb_seginfo.pm_selector = _go32_my_cs();

  kb_installed = TRUE;

  _go32_dpmi_get_protected_mode_interrupt_vector(0x09, &old_kb_seginfo);
  _go32_dpmi_allocate_iret_wrapper(&new_kb_seginfo);
  _go32_dpmi_set_protected_mode_interrupt_vector(0x09, &new_kb_seginfo);
}

void uninstall_keyboard() {
  if(kb_installed == FALSE)
    return;

  kb_installed = FALSE;

  _go32_dpmi_set_protected_mode_interrupt_vector(0x09, &old_kb_seginfo);
  _go32_dpmi_free_iret_wrapper(&new_kb_seginfo);
}

void check_keyboard() {
  if(keyboard[ESC] == TRUE)
    quit_prog = TRUE;
}
---[eof]---

---[test.cpp]---
bool quit_prog = FALSE;

void main() {
  install_keyboard();

  do {
    // do stuff
    check_keyboard();
  } while(quit_prog != TRUE);

  uninstall_keyboard();
}
---[eof]---

HTH,
	.(Trancelucid).
	  .  Jaune  .


Anthony Graham wrote:
> 
> I've been experimenting with the __dmpi and _go32 things and would like to
> know if anyone would be able to tell me how to do a simple keyboard routine
> (no assembly) that increases a variable whenever a key is pressed, (I'll
> make the thing a little more useful later, I just need to know how to
> replace the default keyboard interrupt routine without it crashing), also
> putting it back to normal after Q is pressed would be really helpful too.
> 
> thanks loads.
> 
> -Anthony

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