1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
/* -*- linux-c -*- ------------------------------------------------------- *
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
* Copyright 2009 Intel Corporation; author H. Peter Anvin
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
*
* ----------------------------------------------------------------------- */
/*
* Very simple screen I/O
* XXX: Probably should add very simple serial I/O?
*/
#include "boot.h"
/*
* These functions are in .inittext so they can be used to signal
* error during initialization.
*/
void __attribute__((section(".inittext"))) putchar(int ch)
{
struct biosregs ireg;
if (ch == '\n')
putchar('\r'); /* \n -> \r\n */
initregs(&ireg);
ireg.bx = 0x0007;
ireg.cx = 0x0001;
ireg.ah = 0x0e;
ireg.al = ch;
intcall(0x10, &ireg, NULL);
}
void __attribute__((section(".inittext"))) puts(const char *str)
{
while (*str)
putchar(*str++);
}
/*
* Read the CMOS clock through the BIOS, and return the
* seconds in BCD.
*/
static u8 gettime(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
ireg.ah = 0x02;
intcall(0x1a, &ireg, &oreg);
return oreg.dh;
}
/*
* Read from the keyboard
*/
int getchar(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
/* ireg.ah = 0x00; */
intcall(0x16, &ireg, &oreg);
return oreg.al;
}
static int kbd_pending(void)
{
struct biosregs ireg, oreg;
initregs(&ireg);
ireg.ah = 0x01;
intcall(0x16, &ireg, &oreg);
return !(oreg.eflags & X86_EFLAGS_ZF);
}
void kbd_flush(void)
{
for (;;) {
if (!kbd_pending())
break;
getchar();
}
}
int getchar_timeout(void)
{
int cnt = 30;
int t0, t1;
t0 = gettime();
while (cnt) {
if (kbd_pending())
return getchar();
t1 = gettime();
if (t0 != t1) {
cnt--;
t0 = t1;
}
}
return 0; /* Timeout! */
}
|
