src/lib/vga/text.c

   1 /*
   2  VGA Text Manager
   3  (C) 2015 OS-DK.
   4  (C) 2015 VOSystems.
   5 */
   6
   7 #include<sysvga.h>
   8 #include<types.h>
   9
  10 static unsigned short *ch_vram;
  11 static unsigned short X,Y,pos;
  12 static unsigned char attr;
  13
  14 enum VGA_PORTS{
  15                 CRTC_ADDR = 0x3D4,
  16                 CRTC_DATA = 0x3D5
  17 };
  18
  19 enum CGTC_REGS{
  20                 CRTC_CURSOR_H = 0x0E,
  21                 CRTC_CURSOR_L = 0x0F
  22 };
  23
  24 void init_sysvga(void)
  25 {
  26         ch_vram=(unsigned short*)0xb8000;
  27         X=0;    Y=0;    pos=0;
  28         DisplayColorChangeChar(White,Black);
  29 }
  30
  31 void ClearScreen(void)
  32 {
  33         ch_vram=(unsigned short*)0xb8000;
  34         X=0;Y=0;
  35         while(ch_vram<(unsigned short*)0xc0000)
  36         {
  37                 *ch_vram++ =NULL;
  38         }
  39         ch_vram=(unsigned short*)0xb8000;
  40
  41         vga_text_update_cursor();
  42
  43         return;
  44 }
  45
  46 void vga_text_update_cursor(void)
  47 {
  48         pos=(Y*80)+X;
  49         subset_out8(CRTC_ADDR, CRTC_CURSOR_H);
  50         subset_out8(CRTC_DATA, pos >> 8     );
  51         subset_out8(CRTC_ADDR, CRTC_CURSOR_L);
  52         subset_out8(CRTC_DATA, pos & 0xFF   );
  53 }
  54
  55 void DisplayOutputChar(const char ch)
  56 {
  57         if(ch=='\n'){
  58                 if(Y<25){
  59                         ch_vram+=(80-X);
  60                         X=0;
  61                         Y++;
  62                         pos=Y*80;
  63                 }else{
  64                         ShiftDisplayChar(1);
  65                         ch_vram+=(80-X);
  66                         pos=Y*80;
  67                         X=0;
  68                 }
  69         }else if(ch=='\r'){
  70                 ch_vram-=X;
  71                 X=0;
  72
  73         }else if(ch=='\t'){
  74                 DisplayOutputChar(' ');
  75                 DisplayOutputChar(' ');
  76
  77         }else{
  78                 *ch_vram++ = (((attr)<<8) | ch);
  79
  80         }
  81 }
  82
  83 void ShiftDisplayChar(unsigned int len)
  84 {
  85         unsigned int *sc1,*sc2;
  86         sc1=0xb8000;    sc2=0xb8000+(80*2);
  87         while(sc2<=0xc0000)*sc1++ = *sc2++;
  88         if(len>1){
  89                 len--;
  90                 ShiftDisplayChar(len);
  91         }
  92 }
  93
  94 void DisplayColorChangeChar(Color_t fore, Color_t back)
  95 {
  96         attr |= (back<<4) | (fore & 0x0f);
  97 }