sys/src/9/kw/cga.c

   1 #include "u.h"
   2 #include "../port/lib.h"
   3 #include "mem.h"
   4 #include "dat.h"
   5 #include "fns.h"
   6 #include "../port/error.h"
   7
   8 enum {
   9         Black,
  10         Blue,
  11         Green,
  12         Cyan,
  13         Red,
  14         Magenta,
  15         Brown,
  16         Grey,
  17
  18         Bright = 0x08,
  19         Blinking = 0x80,
  20
  21         Yellow = Bright|Brown,
  22         White = Bright|Grey,
  23 };
  24
  25 enum {
  26         Width           = 80*2,
  27         Height          = 25,
  28
  29         Attr            = (Black<<4)|Grey,      /* high nibble background
  30                                                  * low foreground
  31                                                  */
  32 };
  33
  34 #define CGASCREENBASE   ((uchar*)KADDR(0xB8000))
  35
  36 #define inb(x)          0       /* TODO */
  37 #define outb(x, y)                      /* TODO */
  38
  39 static int cgapos;
  40 static Lock cgascreenlock;
  41
  42 static uchar
  43 cgaregr(int index)
  44 {
  45         USED(index);
  46         outb(0x3D4, index);
  47         return inb(0x3D4+1) & 0xFF;
  48 }
  49
  50 static void
  51 cgaregw(int index, int data)
  52 {
  53         USED(index, data);
  54         outb(0x3D4, index);
  55         outb(0x3D4+1, data);
  56 }
  57
  58 static void
  59 movecursor(void)
  60 {
  61         cgaregw(0x0E, (cgapos/2>>8) & 0xFF);
  62         cgaregw(0x0F, cgapos/2 & 0xFF);
  63         CGASCREENBASE[cgapos+1] = Attr;
  64 }
  65
  66 static void
  67 cgascreenputc(int c)
  68 {
  69         int i;
  70         uchar *p;
  71
  72         if(c == '\n'){
  73                 cgapos = cgapos/Width;
  74                 cgapos = (cgapos+1)*Width;
  75         }
  76         else if(c == '\t'){
  77                 i = 8 - ((cgapos/2)&7);
  78                 while(i-->0)
  79                         cgascreenputc(' ');
  80         }
  81         else if(c == '\b'){
  82                 if(cgapos >= 2)
  83                         cgapos -= 2;
  84                 cgascreenputc(' ');
  85                 cgapos -= 2;
  86         }
  87         else{
  88                 CGASCREENBASE[cgapos++] = c;
  89                 CGASCREENBASE[cgapos++] = Attr;
  90         }
  91         if(cgapos >= Width*Height){
  92                 memmove(CGASCREENBASE, &CGASCREENBASE[Width], Width*(Height-1));
  93                 p = &CGASCREENBASE[Width*(Height-1)];
  94                 for(i=0; i<Width/2; i++){
  95                         *p++ = ' ';
  96                         *p++ = Attr;
  97                 }
  98                 cgapos = Width*(Height-1);
  99         }
 100         movecursor();
 101 }
 102
 103 static void
 104 cgascreenputs(char* s, int n)
 105 {
 106         if(!islo()){
 107                 /*
 108                  * Don't deadlock trying to
 109                  * print in an interrupt.
 110                  */
 111                 if(!canlock(&cgascreenlock))
 112                         return;
 113         }
 114         else
 115                 lock(&cgascreenlock);
 116
 117         while(n-- > 0)
 118                 cgascreenputc(*s++);
 119
 120         unlock(&cgascreenlock);
 121 }
 122
 123 void
 124 screeninit(void)
 125 {
 126
 127         cgapos = cgaregr(0x0E)<<8;
 128         cgapos |= cgaregr(0x0F);
 129         cgapos *= 2;
 130
 131         screenputs = cgascreenputs;
 132 }