src/threads/io.h

   1 /* This file is derived from source code used in MIT's 6.828
   2    course.  The original copyright notice is reproduced in full
   3    below. */
   4
   5 /*
   6  * Copyright (C) 1997 Massachusetts Institute of Technology
   7  *
   8  * This software is being provided by the copyright holders under the
   9  * following license. By obtaining, using and/or copying this software,
  10  * you agree that you have read, understood, and will comply with the
  11  * following terms and conditions:
  12  *
  13  * Permission to use, copy, modify, distribute, and sell this software
  14  * and its documentation for any purpose and without fee or royalty is
  15  * hereby granted, provided that the full text of this NOTICE appears on
  16  * ALL copies of the software and documentation or portions thereof,
  17  * including modifications, that you make.
  18  *
  19  * THIS SOFTWARE IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE NO
  20  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE,
  21  * BUT NOT LIMITATION, COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR
  22  * WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR
  23  * THAT THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY
  24  * THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS. COPYRIGHT
  25  * HOLDERS WILL BEAR NO LIABILITY FOR ANY USE OF THIS SOFTWARE OR
  26  * DOCUMENTATION.
  27  *
  28  * The name and trademarks of copyright holders may NOT be used in
  29  * advertising or publicity pertaining to the software without specific,
  30  * written prior permission. Title to copyright in this software and any
  31  * associated documentation will at all times remain with copyright
  32  * holders. See the file AUTHORS which should have accompanied this software
  33  * for a list of all copyright holders.
  34  *
  35  * This file may be derived from previously copyrighted software. This
  36  * copyright applies only to those changes made by the copyright
  37  * holders listed in the AUTHORS file. The rest of this file is covered by
  38  * the copyright notices, if any, listed below.
  39  */
  40
  41 #ifndef THREADS_IO_H
  42 #define THREADS_IO_H
  43
  44 #include <stddef.h>
  45 #include <stdint.h>
  46
  47 /* Reads and returns a byte from PORT. */
  48 static inline uint8_t
  49 inb (uint16_t port)
  50 {
  51   /* See [IA32-v2a] "IN". */
  52   uint8_t data;
  53   asm volatile ("inb %w1,%0" : "=a" (data) : "d" (port));
  54   return data;
  55 }
  56
  57 /* Reads CNT bytes from PORT, one after another, and stores them
  58    into the buffer starting at ADDR. */
  59 static inline void
  60 insb (uint16_t port, void *addr, size_t cnt)
  61 {
  62   /* See [IA32-v2a] "INS". */
  63   asm volatile ("cld; repne; insb"
  64                 : "=D" (addr), "=c" (cnt)
  65                 : "d" (port), "0" (addr), "1" (cnt)
  66                 : "memory", "cc");
  67 }
  68
  69 /* Reads and returns 16 bits from PORT. */
  70 static inline uint16_t
  71 inw (uint16_t port)
  72 {
  73   uint16_t data;
  74   /* See [IA32-v2a] "IN". */
  75   asm volatile ("inw %w1,%0" : "=a" (data) : "d" (port));
  76   return data;
  77 }
  78
  79 /* Reads CNT 16-bit (halfword) units from PORT, one after
  80    another, and stores them into the buffer starting at ADDR. */
  81 static inline void
  82 insw (uint16_t port, void *addr, size_t cnt)
  83 {
  84   /* See [IA32-v2a] "INS". */
  85   asm volatile ("cld; repne; insw"
  86                 : "=D" (addr), "=c" (cnt)
  87                 : "d" (port), "0" (addr), "1" (cnt)
  88                 : "memory", "cc");
  89 }
  90
  91 /* Reads and returns 32 bits from PORT. */
  92 static inline uint32_t
  93 inl (uint16_t port)
  94 {
  95   /* See [IA32-v2a] "IN". */
  96   uint32_t data;
  97   asm volatile ("inl %w1,%0" : "=a" (data) : "d" (port));
  98   return data;
  99 }
 100
 101 /* Reads CNT 32-bit (word) units from PORT, one after another,
 102    and stores them into the buffer starting at ADDR. */
 103 static inline void
 104 insl (uint16_t port, void *addr, size_t cnt)
 105 {
 106   /* See [IA32-v2a] "INS". */
 107   asm volatile ("cld; repne; insl"
 108                 : "=D" (addr), "=c" (cnt)
 109                 : "d" (port), "0" (addr), "1" (cnt)
 110                 : "memory", "cc");
 111 }
 112
 113 /* Writes byte DATA to PORT. */
 114 static inline void
 115 outb (uint16_t port, uint8_t data)
 116 {
 117   /* See [IA32-v2b] "OUT". */
 118   asm volatile ("outb %0,%w1" : : "a" (data), "d" (port));
 119 }
 120
 121 /* Writes to PORT each byte of data in the CNT-byte buffer
 122    starting at ADDR. */
 123 static inline void
 124 outsb (uint16_t port, const void *addr, size_t cnt)
 125 {
 126   /* See [IA32-v2b] "OUTS". */
 127   asm volatile ("cld; repne; outsb"
 128                 : "=S" (addr), "=c" (cnt)
 129                 : "d" (port), "0" (addr), "1" (cnt)
 130                 : "cc");
 131 }
 132
 133 /* Writes the 16-bit DATA to PORT. */
 134 static inline void
 135 outw (uint16_t port, uint16_t data)
 136 {
 137   /* See [IA32-v2b] "OUT". */
 138   asm volatile ("outw %0,%w1" : : "a" (data), "d" (port));
 139 }
 140
 141 /* Writes to PORT each 16-bit unit (halfword) of data in the
 142    CNT-halfword buffer starting at ADDR. */
 143 static inline void
 144 outsw (uint16_t port, const void *addr, size_t cnt)
 145 {
 146   /* See [IA32-v2b] "OUTS". */
 147   asm volatile ("cld; repne; outsw"
 148                 : "=S" (addr), "=c" (cnt)
 149                 : "d" (port), "0" (addr), "1" (cnt)
 150                 : "cc");
 151 }
 152
 153 /* Writes the 32-bit DATA to PORT. */
 154 static inline void
 155 outl (uint16_t port, uint32_t data)
 156 {
 157   /* See [IA32-v2b] "OUT". */
 158   asm volatile ("outl %0,%w1" : : "a" (data), "d" (port));
 159 }
 160
 161 /* Writes to PORT each 32-bit unit (word) of data in the CNT-word
 162    buffer starting at ADDR. */
 163 static inline void
 164 outsl (uint16_t port, const void *addr, size_t cnt)
 165 {
 166   /* See [IA32-v2b] "OUTS". */
 167   asm volatile ("cld; repne; outsl"
 168                 : "=S" (addr), "=c" (cnt)
 169                 : "d" (port), "0" (addr), "1" (cnt)
 170                 : "cc");
 171 }
 172
 173 #endif /* threads/io.h */