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Programmer-Preferred Graphics Routines

IP.com Disclosure Number: IPCOM000041595D
Original Publication Date: 1984-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Stephens, LK: AUTHOR

Abstract

Schematic generators for computer graphics displays employ a symbol table or tables from which the user can select symbols to be placed on the screen. To effectively and efficiently carry out this architecture, it is necessary to create two graphics routines to do the "bit-pump" from the computer's memory to the graphic display memory. This is accomplished by modifying the graphics routines of the BASIC programming language to a new format. The new format used is as follows: CALL PLACE (X,Y,SEGMENT, OFFSET) -Put with PSET OPTION CALL OVERLAY (X,Y,SEGMENT, OFFSET) -Put with XOR SEGMENT in both cases is the Segment Register. OFFSET in both cases is an offset into the Segment Register. The Segment Register does not need to be BASIC's Segment Register.

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Programmer-Preferred Graphics Routines

Schematic generators for computer graphics displays employ a symbol table or tables from which the user can select symbols to be placed on the screen. To effectively and efficiently carry out this architecture, it is necessary to create two graphics routines to do the "bit-pump" from the computer's memory to the graphic display memory. This is accomplished by modifying the graphics routines of the BASIC programming language to a new format. The new format used is as follows: CALL PLACE (X,Y,SEGMENT, OFFSET) -Put with PSET OPTION CALL OVERLAY (X,Y,SEGMENT, OFFSET) -Put with XOR SEGMENT in both cases is the Segment Register. OFFSET in both cases is an offset into the Segment Register. The Segment Register does not need to be BASIC's Segment Register. This allows the user to use a memory segment not previously employed by BASIC. The programmer loads a predefined symbol table into a buffer outside the memory space allocated for BASIC and the Disc Operating System (DOS). The symbol table contents can then be accessed efficiently by specifying the data segment and offset on which the particular item resides. The first item is located at (Items*2+2) in the symbol table. If one set offset = (Items*2+2), then one could invoke a PUT of that item by saying: CALL PLACE (X,Y,SEGMENT, OFFSET)

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