sys/src/9/pc/vgax.c

   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
  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
  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 }