1/*
2 * Copyright (c) 1998 Robert Nordier
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are freely
6 * permitted provided that the above copyright notice and this
7 * paragraph and the following disclaimer are duplicated in all
8 * such forms.
9 *
10 * This software is provided "AS IS" and without any express or
11 * implied warranties, including, without limitation, the implied
12 * warranties of merchantability and fitness for a particular
13 * purpose.
14 *
| 1/*
2 * Copyright (c) 1998 Robert Nordier
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are freely
6 * permitted provided that the above copyright notice and this
7 * paragraph and the following disclaimer are duplicated in all
8 * such forms.
9 *
10 * This software is provided "AS IS" and without any express or
11 * implied warranties, including, without limitation, the implied
12 * warranties of merchantability and fitness for a particular
13 * purpose.
14 *
|
15 * $FreeBSD: head/sys/boot/i386/boot2/sio.S 220337 2011-04-04 18:23:55Z rdivacky $
| 15 * $FreeBSD: head/sys/boot/i386/boot2/sio.S 241301 2012-10-06 20:08:29Z avg $
|
16 */
17
18 .set SIO_PRT,SIOPRT # Base port
19 .set SIO_FMT,SIOFMT # 8N1
20
21 .globl sio_init
22 .globl sio_flush
23 .globl sio_putc
24 .globl sio_getc
25 .globl sio_ischar
26
| 16 */
17
18 .set SIO_PRT,SIOPRT # Base port
19 .set SIO_FMT,SIOFMT # 8N1
20
21 .globl sio_init
22 .globl sio_flush
23 .globl sio_putc
24 .globl sio_getc
25 .globl sio_ischar
26
|
27/* void sio_init(int div) */
| 27/* int sio_init(int div) */
|
28
29sio_init: pushl %eax
30 movw $SIO_PRT+0x3,%dx # Data format reg
31 movb $SIO_FMT|0x80,%al # Set format
32 outb %al,(%dx) # and DLAB
33 subb $0x3,%dl # Divisor latch reg
34 popl %eax
35 outw %ax,(%dx) # BPS
36 movw $SIO_PRT+0x3,%dx # Data format reg
37 movb $SIO_FMT,%al # Clear
38 outb %al,(%dx) # DLAB
39 incl %edx # Modem control reg
40 movb $0x3,%al # Set RTS,
41 outb %al,(%dx) # DTR
42 incl %edx # Line status reg
43 call sio_flush
44 ret
45
| 28
29sio_init: pushl %eax
30 movw $SIO_PRT+0x3,%dx # Data format reg
31 movb $SIO_FMT|0x80,%al # Set format
32 outb %al,(%dx) # and DLAB
33 subb $0x3,%dl # Divisor latch reg
34 popl %eax
35 outw %ax,(%dx) # BPS
36 movw $SIO_PRT+0x3,%dx # Data format reg
37 movb $SIO_FMT,%al # Clear
38 outb %al,(%dx) # DLAB
39 incl %edx # Modem control reg
40 movb $0x3,%al # Set RTS,
41 outb %al,(%dx) # DTR
42 incl %edx # Line status reg
43 call sio_flush
44 ret
45
|
46/* void sio_flush(void) */
| 46/* int sio_flush(void) */
|
47
| 47
|
48sio_flush.0: call sio_getc.1 # Get character
49sio_flush: call sio_ischar # Check for character
50 jnz sio_flush.0 # Till none
51 ret # To caller
| 48sio_flush: xorl %eax,%eax # Return value
49 xorl %ecx,%ecx # Timeout
50 movb $0x80,%ch # counter
51sio_flush.1: call sio_ischar # Check for character
52 jz sio_flush.2 # Till none
53 loop sio_flush.1 # or counter is zero
54 movb $1, %al # Exhausted all tries
55sio_flush.2: ret # To caller
|
52
53/* void sio_putc(int c) */
54
55sio_putc: pushl %eax
56 movw $SIO_PRT+0x5,%dx # Line status reg
57 xor %ecx,%ecx # Timeout
58 movb $0x40,%ch # counter
59sio_putc.1: inb (%dx),%al # Transmitter
60 testb $0x20,%al # buffer empty?
61 loopz sio_putc.1 # No
62 jz sio_putc.2 # If timeout
63 popl %eax # Get the character
64 subb $0x5,%dl # Transmitter hold reg
65 outb %al,(%dx) # Write character
66sio_putc.2: ret # To caller
67
68/* int sio_getc(void) */
69
70sio_getc: call sio_ischar # Character available?
71 jz sio_getc # No
72sio_getc.1: subb $0x5,%dl # Receiver buffer reg
73 inb (%dx),%al # Read character
74 ret # To caller
75
76/* int sio_ischar(void) */
77
78sio_ischar: movw $SIO_PRT+0x5,%dx # Line status register
79 xorl %eax,%eax # Zero
80 inb (%dx),%al # Received data
81 andb $0x1,%al # ready?
82 ret # To caller
| 56
57/* void sio_putc(int c) */
58
59sio_putc: pushl %eax
60 movw $SIO_PRT+0x5,%dx # Line status reg
61 xor %ecx,%ecx # Timeout
62 movb $0x40,%ch # counter
63sio_putc.1: inb (%dx),%al # Transmitter
64 testb $0x20,%al # buffer empty?
65 loopz sio_putc.1 # No
66 jz sio_putc.2 # If timeout
67 popl %eax # Get the character
68 subb $0x5,%dl # Transmitter hold reg
69 outb %al,(%dx) # Write character
70sio_putc.2: ret # To caller
71
72/* int sio_getc(void) */
73
74sio_getc: call sio_ischar # Character available?
75 jz sio_getc # No
76sio_getc.1: subb $0x5,%dl # Receiver buffer reg
77 inb (%dx),%al # Read character
78 ret # To caller
79
80/* int sio_ischar(void) */
81
82sio_ischar: movw $SIO_PRT+0x5,%dx # Line status register
83 xorl %eax,%eax # Zero
84 inb (%dx),%al # Received data
85 andb $0x1,%al # ready?
86 ret # To caller
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