include/linux/vt_buffer.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *      include/linux/vt_buffer.h -- Access to VT screen buffer
   4  *
   5  *      (c) 1998 Martin Mares <mj@ucw.cz>
   6  *
   7  *      This is a set of macros and functions which are used in the
   8  *      console driver and related code to access the screen buffer.
   9  *      In most cases the console works with simple in-memory buffer,
  10  *      but when handling hardware text mode consoles, we store
  11  *      the foreground console directly in video memory.
  12  */
  13
  14 #ifndef _LINUX_VT_BUFFER_H_
  15 #define _LINUX_VT_BUFFER_H_
  16
  17 #include <linux/string.h>
  18
  19 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_MDA_CONSOLE)
  20 #include <asm/vga.h>
  21 #endif
  22
  23 #ifndef VT_BUF_HAVE_RW
  24 #define scr_writew(val, addr) (*(addr) = (val))
  25 #define scr_readw(addr) (*(addr))
  26 #endif
  27
  28 #ifndef VT_BUF_HAVE_MEMSETW
  29 static inline void scr_memsetw(u16 *s, u16 c, unsigned int count)
  30 {
  31 #ifdef VT_BUF_HAVE_RW
  32         count /= 2;
  33         while (count--)
  34                 scr_writew(c, s++);
  35 #else
  36         memset16(s, c, count / 2);
  37 #endif
  38 }
  39 #endif
  40
  41 #ifndef VT_BUF_HAVE_MEMCPYW
  42 static inline void scr_memcpyw(u16 *d, const u16 *s, unsigned int count)
  43 {
  44 #ifdef VT_BUF_HAVE_RW
  45         count /= 2;
  46         while (count--)
  47                 scr_writew(scr_readw(s++), d++);
  48 #else
  49         memcpy(d, s, count);
  50 #endif
  51 }
  52 #endif
  53
  54 #ifndef VT_BUF_HAVE_MEMMOVEW
  55 static inline void scr_memmovew(u16 *d, const u16 *s, unsigned int count)
  56 {
  57 #ifdef VT_BUF_HAVE_RW
  58         if (d < s)
  59                 scr_memcpyw(d, s, count);
  60         else {
  61                 count /= 2;
  62                 d += count;
  63                 s += count;
  64                 while (count--)
  65                         scr_writew(scr_readw(--s), --d);
  66         }
  67 #else
  68         memmove(d, s, count);
  69 #endif
  70 }
  71 #endif
  72
  73 #endif