root/include/asm/io.h

/* */

INCLUDED FROM

DEFINITIONS

1. outb
2. outb_p
3. inb
4. inb_p

   1 #ifndef _ASM_IO_H
   2 #define _ASM_IO_H
   3 
   4 /*
   5  * Thanks to James van Artsdalen for a better timing-fix than
   6  * the two short jumps: using outb's to a nonexistent port seems
   7  * to guarantee better timings even on fast machines.
   8  *
   9  *              Linus
  10  */
  11 
  12 extern void inline outb(char value, unsigned short port)
     /*  */
  13 {
  14 __asm__ volatile ("outb %0,%1"
  15                 ::"a" ((char) value),"d" ((unsigned short) port));
  16 }
  17 
  18 extern void inline outb_p(char value, unsigned short port)
     /*  */
  19 {
  20 __asm__ volatile ("outb %0,%1\n\t"
  21                   "outb %0,$0x80\n\t"
  22                   "outb %0,$0x80\n\t"
  23                   "outb %0,$0x80\n\t"
  24                   "outb %0,$0x80"
  25                 ::"a" ((char) value),"d" ((unsigned short) port));
  26 }
  27 
  28 extern unsigned char inline inb(unsigned short port)
     /*  */
  29 {
  30         unsigned char _v;
  31 __asm__ volatile ("inb %1,%0"
  32                 :"=a" (_v):"d" ((unsigned short) port));
  33         return _v;
  34 }
  35 
  36 extern unsigned char inline inb_p(unsigned short port)
     /*  */
  37 {
  38         unsigned char _v;
  39 __asm__ volatile ("inb %1,%0\n\t"
  40                   "outb %0,$0x80\n\t"
  41                   "outb %0,$0x80\n\t"
  42                   "outb %0,$0x80\n\t"
  43                   "outb %0,$0x80"
  44                 :"=a" (_v):"d" ((unsigned short) port));
  45         return _v;
  46 }
  47 
  48 #endif

/* */