sys/src/9/alphapc/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 #include "io.h"
   8
   9 enum {
  10         Width           = 160,
  11         Height          = 25,
  12
  13         Attr            = 0x4f, /* white on blue */
  14 };
  15
  16 static ulong    cgabase;
  17 #define CGASCREENBASE   ((uchar*)cgabase)
  18
  19 static int cgapos;
  20 static int screeninitdone;
  21 static Lock cgascreenlock;
  22
  23 static uchar
  24 cgaregr(int index)
  25 {
  26         outb(0x3D4, index);
  27         return inb(0x3D4+1) & 0xFF;
  28 }
  29
  30 static void
  31 cgaregw(int index, int data)
  32 {
  33         outb(0x3D4, index);
  34         outb(0x3D4+1, data);
  35 }
  36
  37 static void
  38 movecursor(void)
  39 {
  40         cgaregw(0x0E, (cgapos/2>>8) & 0xFF);
  41         cgaregw(0x0F, cgapos/2 & 0xFF);
  42         CGASCREENBASE[cgapos+1] = Attr;
  43 }
  44
  45 static void
  46 cgascreenputc(int c)
  47 {
  48         int i;
  49
  50         if(c == '\n'){
  51                 cgapos = cgapos/Width;
  52                 cgapos = (cgapos+1)*Width;
  53         }
  54         else if(c == '\t'){
  55                 i = 8 - ((cgapos/2)&7);
  56                 while(i-->0)
  57                         cgascreenputc(' ');
  58         }
  59         else if(c == '\b'){
  60                 if(cgapos >= 2)
  61                         cgapos -= 2;
  62                 cgascreenputc(' ');
  63                 cgapos -= 2;
  64         }
  65         else{
  66                 CGASCREENBASE[cgapos++] = c;
  67                 CGASCREENBASE[cgapos++] = Attr;
  68         }
  69         if(cgapos >= Width*Height){
  70                 memmove(CGASCREENBASE, &CGASCREENBASE[Width], Width*(Height-1));
  71                 for (i = Width*(Height-1); i < Width*Height;) {
  72                         CGASCREENBASE[i++] = 0x20;
  73                         CGASCREENBASE[i++] = Attr;
  74                 }
  75                 cgapos = Width*(Height-1);
  76         }
  77         movecursor();
  78 }
  79
  80 void
  81 screeninit(void)
  82 {
  83         cgabase = (ulong)arch->pcimem(0xB8000, 0x8000);
  84
  85         cgapos = cgaregr(0x0E)<<8;
  86         cgapos |= cgaregr(0x0F);
  87         cgapos *= 2;
  88         screeninitdone = 1;
  89 }
  90
  91 static void
  92 cgascreenputs(char* s, int n)
  93 {
  94         if(!screeninitdone)
  95                 return;
  96         if(!islo()){
  97                 /*
  98                  * Don't deadlock trying to
  99                  * print in an interrupt.
 100                  */
 101                 if(!canlock(&cgascreenlock))
 102                         return;
 103         }
 104         else
 105                 lock(&cgascreenlock);
 106
 107         while(n-- > 0)
 108                 cgascreenputc(*s++);
 109
 110         unlock(&cgascreenlock);
 111 }
 112
 113 void (*screenputs)(char*, int) = cgascreenputs;