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From: aek@Apple.COM (Al Kossow) Subject: VT11 instruction set Date: 21 Feb 93 20:43:30 GMT The VT11 instruction set: SET GRAPHIC MODE "1" indicates control word bit 15 0000 set character mode bits 14-11 0001 set short vector mode 0010 set long vector mode 0011 set point mode 0100 set graph x mode 0101 set graph y mode 0110 set relative point mode 0111 spare "1" enables bits 9-7 into the intensity register bit 10 3 bit intensity value bits 9-7 000 minimum intensity 111 maximum intensity set set enables bit 5 into the L.P. interrupt enable register bit 6 1 = L.P. interrupt enabled bit 5 when set enables bit 3 into the blink register bit 4 1 = blink on bit 3 1 enables bits 1-0 into the line registers bit 2 00 solid line bits 1-0 01 long dash 10 short dash 11 dot dash JUMP | 1 | 1 1 0 0 | - - - - - - - - - - - | | 16 bit jump address | +---+---------+-----------------------+ +---------------------+ NOOP | 1 | 1 1 0 1 | - - - - - - - - - - - | +---+---------+-----------------------+ LOAD STATUS REGISTER A 1 indicates control word bit 15 OPCODE for load status A register '1110' will stop the display when set bit 10 when set enables bit 8 into stop interrupt register bit 9 interrupt 11/05 when display stops bit 8 when set enables bit 6 into the L.P. intensity hit register bit 7 0 = point of light pen interaction will be intensified bit 6 1 = point of light pen interaction will not be intensified when set enables bit 4 into italics register bit 5 1= italics 0= normal font bit 4 not used bit 3 halts DPU and resumes in sync with line frequency bit 2 not used bits 1-0 LOAD STATUS REGISTER B 1 indicates control word bit 15 opcode for load status register B '1111' spare bits 10-7 when set, enables bits 0-5 into graphplot increment register bit 6 sets the distance between points executed in graphplot bits 5-0 ..AND FORMAT OF THE DATA WORDS CHARACTER DATA FORMAT (mode 0000) | 0 | 2nd 7bit ASCII CODE | - | 1st 7bit ASCII CODE | +---+---------------------+---+---------------------+ SHORT VECTOR MODE (mode 0001) | 0 | INT | +/- | 6 bits delta X | +/- | 6 bits delta Y | +---+-----+-----+----------------+-----+----------------+ LONG VECTOR DATA FORMAT (mode 0010) | 0 | INT | +/- | - - - | 10 bits delta X | +---+-----+-----+-------+-----------------+ | 0 | - | +/- | - - - | 10 bits delta Y | +---+-----+-----+-------+-----------------+ POINT DATA MODE (mode 0011) | 0 | INT | - - - - | 10 bits X | +---+-----+---------+-----------+ GRAPHPLOT X (mode 0100) | 0 | - - - - - | 10 bit Y coordinate | +---+-----------+---------------------+ GRAPHPLOT Y (mode 0101) | 0 | - - - - - | 10 bit X coordinate | +---+-----------+---------------------+ RELATIVE POINT MODE (mode 0110 ) | 0 | INT | +/- | 6 bits delta X | +/- | 6 bits delta Y | +---+-----+-----+----------------+-----+----------------+ To start the display processor, stuff the display program starting address into the Display Program Counter (172000) Note that there is no way for the PDP11 to STOP the display processor without modifying the display list!
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Last updated October 8, 1999
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