61	planelow = readVRAMplane(VGA,planebase,planeindex,0); //Read low plane!
62	planebase |= 2; //Take the high plane now!
63	planehigh = readVRAMplane(VGA,planebase,planeindex,1); //Read high plane!
64	
65	//Determine the shift for our pixels!
66	shift &= 3; //The shift rotates every 4 pixels
67	shift <<= 1; //Every rotate contains 2 bits
68	bitshift = 6; //Shift for pixel 0!
69	bitshift -= shift; //Get the shift with the actual shift!
70
71	//Get the pixel
72	planelow >>= bitshift; //Shift plane low correct.
73	planelow &= 3; //We're 2 bits only
74
75	planehigh >>= bitshift; //Shift plane high correct
76	planehigh &= 3; //We're 2 bits only
77
78	planehigh <<= 2; //Prepare high plane for combination!
79
80	//Build the result!
81	planelow |= planehigh; //Add high plane to the result!
82	
83	//Source plane bits for all possibilities!
84	return planelow; //Give the result!
85}
86
87/*
88
89SINGLE SHIFT MODE
90
91*/
92
93byte getplanarshiftmode(VGA_Type *VGA, SEQ_DATA *Sequencer, word x) //Planar shift mode!
94{
95	//16-color mode!
96	register byte result; //Init result!
97	register word offset, bit;
98
99	offset = x; //Load x!
100	offset >>= VGA->precalcs.characterclockshift; //Apply pixel DIVIDE when needed!
101
102	bit = offset;
103	bit &= 7; //The bit in the byte (from the start of VRAM byte)! 8 bits = 8 pixels!
104
105	offset >>= 3; //Shift to the byte: every 8 pixels we go up 1 byte!
106	offset += Sequencer->charystart; //VRAM start of row and start map!
107	
108	//Standard VGA processing!
109	result = getBitPlaneBit(VGA,3,offset,bit,1); //Add plane to the result!
110	result <<= 1; //Shift to next plane!
111	result |= getBitPlaneBit(VGA,2,offset,bit,1); //Add plane to the result!
112	result <<= 1; //Shift to next plane!
113	result |= getBitPlaneBit(VGA,1,offset,bit,1); //Add plane to the result!
114	result <<= 1; //Shift to next plane!
115	result |= getBitPlaneBit(VGA,0,offset,bit,1); //Add plane to the result!
116	return result; //Give the result!
117}
118
119//Shiftregister: 2=ShiftRegisterInterleave, 1=Color256ShiftMode. Priority list: 1, 2, 0; So 1&3=256colorshiftmode, 2=ShiftRegisterInterleave, 0=SingleShift.
120//When index0(VGA->registers->GraphicsRegisters.REGISTERS.MISCGRAPHICSREGISTER.AlphaNumericModeDisable)=1, getColorPlanesAlphaNumeric
121//When index1(IGNOREATTRPLANES)=1, getColorPlanesIgnoreAttrPlanes
122
123//http://www.openwatcom.org/index.php/VGA_Fundamentals:
124//Packed Pixel: Color 256 Shift Mode.
125//Parallel Planes: Else case!
126//Interleaved: Shift Register Interleave!
127
128/*
129
130Core functions!
131
132*/
133
134void VGA_Sequencer_GraphicsMode(VGA_Type *VGA, SEQ_DATA *Sequencer, VGA_AttributeInfo *attributeinfo)
135{
136	static agetpixel getpixel_jmptbl[4] = {
137				getplanarshiftmode,
138				getpackedshiftmode,
139				get256colorshiftmode,
140				get256colorshiftmode
141				}; //All the getpixel functionality!
142	attributeinfo->fontpixel = 1; //Graphics attribute is always font enabled!
143	attributeinfo->attribute = getpixel_jmptbl[VGA->registers->GraphicsRegisters.REGISTERS.GRAPHICSMODEREGISTER.ShiftRegister](VGA,Sequencer,Sequencer->activex);
144}

61}
62
63//Planar access to VRAM
64byte readVRAMplane(VGA_Type *VGA, byte plane, word offset, byte is_renderer) //Read from a VRAM plane!
65{
66	if (!VGA) return 0; //Invalid VGA!
67	if (!VGA->VRAM_size) return 0; //No size!
68	word patchedoffset = offset; //Default offset to use!
69
70	if (is_renderer) //First address wrap, next map13&14!
71	{
72		//First, apply addressing mode!
73		patchedoffset = addresswrap(VGA,patchedoffset); //Wrap first!
74		patchedoffset = patch_map1314(VGA,patchedoffset); //Patch MAP13&14!
75	}
76
77	plane &= 3; //Only 4 planes are available!
78
79	register uint_32 fulloffset2;
80	fulloffset2 = plane; //Load full plane!
81	fulloffset2 <<= 16; //Move to the start of the plane!
82	fulloffset2 |= patchedoffset; //Generate full offset!
83
84	if (fulloffset2<VGA->VRAM_size) //VRAM valid, simple check?
85	{
86		return VGA->VRAM[fulloffset2]; //Read the data from VRAM!
87	}
88	return 0; //Nothing there: invalid VRAM!
89}
90
91void writeVRAMplane(VGA_Type *VGA, byte plane, word offset, byte value) //Write to a VRAM plane!
92{
93	if (!VGA) return; //Invalid VGA!
94	if (!VGA->VRAM_size) return; //No size!
95	
96	plane &= 3; //Only 4 planes are available!
97
98	register uint_32 fulloffset2;
99	fulloffset2 = plane; //Load full plane!
100	fulloffset2 <<= 16; //Move to the start of the plane!
101	fulloffset2 |= offset; //Generate full offset!
102	
103	if (fulloffset2<VGA->VRAM_size) //VRAM valid, simple check?
104	{
105		VGA->VRAM[fulloffset2] = value; //Set the data in VRAM!
106		if (plane==2) //Character RAM updated?
107		{
108			VGA_plane2updated(VGA,offset); //Plane 2 has been updated!	
109		}
110	}
111}