/*
SG C Tools 1.1

(C) 1993 Steve Goldsmith
All Rights Reserved

Compiled with HI-TECH C 3.09 (CP/M-80).
*/

#include <hitech.h>
#include <vdc.h>

uchar vdcRegsToSave[] =                 /* vdc registers to save and restore */
{0,1,2,3,4,5,6,7,8,9,10,11,12,13,
22,23,24,25,26,27,28,29,34,35,36};
uchar vdcRegs[sizeof(vdcRegsToSave)-1]; /* saved vdc registers */

uchar  vdcScrHorz;                      /* vars initilized by savevdc() */
uchar  vdcScrVert;
ushort vdcScrSize;
ushort vdcDispMem;
ushort vdcAttrMem;
ushort vdcCharMem;
ushort vdcCharMemSize;
uchar  vdcCharBytes;
ushort vdcBitMapMem;

/* save and restore key vdc registers and initilize 'vdc' vars */

void savevdc(void)
{
  uchar I;

  for(I = 0; I < sizeof(vdcRegs); I++)    /* save key vdc regs */
    vdcRegs[I] = invdc(vdcRegsToSave[I]);
  vdcScrHorz = invdc(vdcHzDisp);          /* init global vdc vars */
  vdcScrVert = invdc(vdcVtDisp);
  vdcScrSize = vdcScrHorz*vdcScrVert;
  vdcDispMem = (invdc(vdcDspStAddrHi) << 8)+invdc(vdcDspStAddrLo);
  vdcAttrMem = (invdc(vdcAttrStAddrHi) << 8)+invdc(vdcAttrStAddrLo);
  if ((invdc(vdcChTotalVt) & 0x1F) > 0x0F)
  {
    vdcCharMem = (invdc(vdcChSetStAddr) & 0xC0) << 8;
    vdcCharBytes = vdcMaxCharBytes;
    vdcCharMemSize = (vdcCharsPerSet*vdcCharBytes) << 1;
  }
  else
  {
    vdcCharMem = (invdc(vdcChSetStAddr) & 0xE0) << 8;
    vdcCharBytes = vdcMaxCharBytes >> 1;
    vdcCharMemSize = (vdcCharsPerSet*vdcCharBytes) << 1;
  }
  vdcBitMapMem = 0;
}

void restorevdc(void)
{
  uchar I;

  for(I = 0; I < sizeof(vdcRegs); I++)  /* restore vdc regs saved with savevdc() */
    outvdc(vdcRegsToSave[I],vdcRegs[I]);
}