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 IS_ENABLED(CONFIG_VGA_CONSOLE) || IS_ENABLED(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
scr_memsetw(u16 * s,u16 c,unsigned int count)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
scr_memcpyw(u16 * d,const u16 * s,unsigned int count)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
scr_memmovew(u16 * d,const u16 * s,unsigned int count)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
74