1 #include "u.h"
2 #include "../port/lib.h"
3 #include "mem.h"
4 #include "dat.h"
5 #include "fns.h"
6 #include "io.h"
7 #include "../port/error.h"
8
9 #define Image IMAGE
10 #include <draw.h>
11 #include <memdraw.h>
12 #include <cursor.h>
13 #include "screen.h"
14
15 static Lock vgaxlock; /* access to index registers */
16
17 int
vgaxi(long port,uchar index)18 vgaxi(long port, uchar index)
19 {
20 uchar data;
21
22 ilock(&vgaxlock);
23 switch(port){
24
25 case Seqx:
26 case Crtx:
27 case Grx:
28 outb(port, index);
29 data = inb(port+1);
30 break;
31
32 case Attrx:
33 /*
34 * Allow processor access to the colour
35 * palette registers. Writes to Attrx must
36 * be preceded by a read from Status1 to
37 * initialise the register to point to the
38 * index register and not the data register.
39 * Processor access is allowed by turning
40 * off bit 0x20.
41 */
42 inb(Status1);
43 if(index < 0x10){
44 outb(Attrx, index);
45 data = inb(Attrx+1);
46 inb(Status1);
47 outb(Attrx, 0x20|index);
48 }
49 else{
50 outb(Attrx, 0x20|index);
51 data = inb(Attrx+1);
52 }
53 break;
54
55 default:
56 iunlock(&vgaxlock);
57 return -1;
58 }
59 iunlock(&vgaxlock);
60
61 return data & 0xFF;
62 }
63
64 int
vgaxo(long port,uchar index,uchar data)65 vgaxo(long port, uchar index, uchar data)
66 {
67 ilock(&vgaxlock);
68 switch(port){
69
70 case Seqx:
71 case Crtx:
72 case Grx:
73 /*
74 * We could use an outport here, but some chips
75 * (e.g. 86C928) have trouble with that for some
76 * registers.
77 */
78 outb(port, index);
79 outb(port+1, data);
80 break;
81
82 case Attrx:
83 inb(Status1);
84 if(index < 0x10){
85 outb(Attrx, index);
86 outb(Attrx, data);
87 inb(Status1);
88 outb(Attrx, 0x20|index);
89 }
90 else{
91 outb(Attrx, 0x20|index);
92 outb(Attrx, data);
93 }
94 break;
95
96 default:
97 iunlock(&vgaxlock);
98 return -1;
99 }
100 iunlock(&vgaxlock);
101
102 return 0;
103 }
104