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inline byte readVRAMdirect(uint_32 start, uint_32 offset)
{
return VGA.VRAM[(start+offset)%VGA.VRAM_size]; //Read with overflow protection!
}
inline void writeVRAMdirect(uint_32 start, uint_32 offset, byte value)
{
VGA.VRAM[(start+offset)%VGA.VRAM_size] = value; //Write with overflow protection!
}
inline byte readVRAMplane(uint_32 start, byte plane, uint_32 offset) //Read from a VRAM plane!
{
return VGA.VRAM[((plane*0x10000)+start+offset)%VGA.VRAM_size]; //Read with overflow protection!
}
inline void writeVRAMplane(uint_32 start, byte plane, uint_32 offset, byte value) //Write to a VRAM plane!
{
VGA.VRAM[((plane*0x10000)+start+offset)%VGA.VRAM_size] = value; //Write with overflow protection!
}
inline void *VGA_planeptr(uint_32 start, byte plane) //Pointer to VRAM plane!
{
return &VGA.VRAM[((plane*0x10000)+start)%VGA.VRAM_size]; //Pointer to the VRAM plane!
}
inline byte getBitPlaneBit(uint_32 start, int plane, uint_32 offset, byte bit)
{
return ((readVRAMplane(start,plane,offset)&(1<<bit))>>bit); //Give the bit!
}
inline void setBitPlaneBit(uint_32 start, int plane, uint_32 offset, byte bit, byte on)
{
writeVRAMplane(start,plane,offset,((readVRAMplane(start,plane,offset)&~(1<<bit)))|(on<<bit)); //Set the bit!
}
byte VGA_getpixel(int x, int y)
{
uint_32 offset; //The offset within the plane!
int plane; //The plane!
int pixel;
switch (VGA.info.VRAMmode)
{
case 2: //Mono: take bit out of bitplane 0?
offset = getVRAMScanlineStart(y); //The starting offset!
offset += (x/8)*getVRAMMemAddrSize(); //Add X!
return getBitPlaneBit(VGA.info.startMap,0,offset,(x%8)); //Give the bit representing the pixel!
case 4: //Shift register interleave = packed shift mode?
offset = getVRAMScanLineStart(y); //The starting offset of the row!
offset += (x/4)*getVRAMMemAddrSize(); //Add X!
plane = (x/4)%2; //The plane to start, 0 or 1!
pixel = x%4; //The pixel we need to get!
return getBitPlaneBit(VGA.info.startMap,plane+2,offset,7-(pixel*2))*8+ //Plane highest
getBitPlaneBit(VGA.info.startMap,plane+2,offset,7-(pixel*2))*4+ //Plane lower!
getBitPlaneBit(VGA.info.startMap,plane,offset,6-(pixel*2))*2+ //Plane highest
getBitPlaneBit(VGA.info.startMap,plane,offset,6-(pixel*2))+ //Plane lower!
case 16: //Planar shift?
offset = getVRAMScanLineStart(y); //The starting offset of the row!
offset += (x/8)*getVRAMMemAddrSize(); //Add X!
return getBitPlaneBit(VGA.info.startMap,0,offset,(x%8))+ //Bit 0!
getBitPlaneBit(VGA.info.startMap,1,offset,(x%8))*2+ //Bit 1!
getBitPlaneBit(VGA.info.startMap,2,offset,(x%8))*4+ //Bit 2!
getBitPlaneBit(VGA.info.startMap,3,offset,(x%8))*8+ //Bit 3!
case 256: //256 color shift mode?
offset = getVRAMScanlineStart(y); //The starting offset!
offset += ((x/4)*getVRAMMemAddrSize()); //Add X!
plane = (x%4); //The plane: we're spread over the planes!
return readVRAMplane(VGA.info.startMap,plane,offset); //Give the bit representing the pixel!
}
}
void VGA_putpixel(int x, int y, byte color)
{
uint_32 offset; //The offset within the plane!
int plane; //The plane!
int pixel;
byte colorbuf; //Buffer!
switch (VGA.info.VRAMmode)
{
case 2: //Mono: take bit out of bitplane 0?
offset = getVRAMScanlineStart(y); //The starting offset!
offset += (x/8)*getVRAMMemAddrSize(); //Add X!
setBitPlaneBit(VGA.info.startMap,0,offset,(x%8),(color%2)); //Give the bit representing the pixel!
case 4: //Shift register interleave = packed shift mode?
offset = getVRAMScanLineStart(y); //The starting offset of the row!
offset += (x/4)*getVRAMMemAddrSize(); //Add X!
plane = (x/4)%2; //The plane to start, 0 or 1!
pixel = x%4; //The pixel we need to get!
colorbuf = (color&0x3); //The actual color with overflow protection!
setBitPlaneBit(VGA.info.startMap,plane+2,offset,7-(pixel*2),((colorbuf&0x8)>>3)); //Plane highest
setBitPlaneBit(VGA.info.startMap,plane+2,offset,7-(pixel*2),((colorbuf&0x4)>>2)); //Plane lower!
setBitPlaneBit(VGA.info.startMap,plane,offset,6-(pixel*2),((colorbuf&0x2)>>1)); //Plane highest
setBitPlaneBit(VGA.info.startMap,plane,offset,6-(pixel*2),(colorbuf&0x1)); //Plane lower!
case 16: //Planar shift?
offset = getVRAMScanLineStart(y); //The starting offset of the row!
offset += (x/8)*getVRAMMemAddrSize(); //Add X!
setBitPlaneBit(VGA.info.startMap,0,offset,(x%8),(colorbuf&0x1)); //Bit 0!
setBitPlaneBit(VGA.info.startMap,1,offset,(x%8),(colorbuf&0x2)>>1); //Bit 1!
setBitPlaneBit(VGA.info.startMap,2,offset,(x%8),(colorbuf&0x4)>>2); //Bit 2!
setBitPlaneBit(VGA.info.startMap,3,offset,(x%8),(colorbuf&0x8)>>3); //Bit 3!
case 256: //256 color shift mode?
offset = getVRAMScanlineStart(y); //The starting offset!
offset += ((x/4)*getVRAMMemAddrSize()); //Add X!
plane = (x%4); //The plane: we're spread over the planes!
writeVRAMplane(VGA.info.startMap,plane,offset); //Give the bit representing the pixel!
}
}
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