Graphics computer

• US 6,677,950 B1
• Filed: 12/22/1997
• Issued: 01/13/2004
• Est. Priority Date: 12/17/1993
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Hitachi, Ltd.
• Inventors: Ohba, Mamoru, Minami, Rika, Watabe, Mitsuru, Katsura, Koyo
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US08/996,151
• Time in Patent Office: 2,213 Days
• Field of Search: 345/503, 345/505, 345/520, 345/545, 345/567, 345/568, 345/807, 711/202
• US Class Current: 345/503
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves

Abstract

To reduce the hardware of the graphics computer in size and reduce the cost of the hardware, the frame buffer and the main memory are united into one unit to process graphics data in the CPU. The frame buffer is arranged in the main memory, and the graphics computer includes a DMAC used to read pixel data from the frame buffer for display, a display used to receive the pixel data and display it on a display device, such as an LCD, etc., and memories used to store the procedure used by the CPU to draw the pixel data in the said frame buffer. Especially, the said memories are formed so that a single function procedure and 2 multifunction procedure can be selected to suit the drawing object. In addition, the single function procedure includes 2 line drawing procedure that uses data tables and 2 multivalue expansion procedure that uses a pattern table and a mask table. Since the frame buffer and the main memory are united into one unit, the CPU can be used to process graphics data. Thus, the graphics computer hardware is reduced in size and the cost of the hardware is reduced.

Claims

1. A method of operating a microcomputer comprising the steps of:

computing, at a central processing unit (CPU), data to be displayed on a raster scanning type display unit;

carrying addresses to specify a destination of said data in a first address bus connected to said CPU;

storing said data in a memory connected to a second address bus;

storing address conversion data set by said CPU in registers; and

converting, at an address converter, addresses received from the first address bus and outputting converted addresses to the second address bus in accordance with the address conversion information set by said CPU.

2. The method of operating a microcomputer as claimed in claim 1, wherein said address converter is provided with first information that specifies an area in said memory to convert addresses according to address conversion information stored in said registers, and addresses received from the first address bus according to said first information in said address converter.

3. The method of operating a microcomputer as claimed in claim 2, wherein said address converter is provided with second information used to obtain a first field of a XS bit from a lower part of an address according to address conversion information stored in said registers and third information used to distinguish a second field of a YS bit from a third field, and to exchange the second and third fields to convert addresses in said address converter.

4. The method of operating a microcomputer as claimed in claim 3, wherein the exchanging of the second and third fields in said address converter operates on an address received from the first address bus according to said first information.

5. The method of operating a microcomputer as claimed in claim 1 wherein said address converter is provided with second information used to obtain a first field of a XS bit from a lower part of an address according to address conversion information stored in said registers and third information used to distinguish a second field of a YS bit from a third field, and to exchange the second and third fields to convert addresses in said address converter.

6. A method of line drawing comprising the steps of:

generating information to select a draw method from an absolute value of a difference between start and end coordinates of a subject line to generate input information using a selected draw method;

storing vector data in a data storage unit at an address of the absolute value of the difference between the start and end coordinates;

generating equations and constants to generate a line from the start and end coordinates; and

drawing a fixed area for stored data received from said data storage unit.

7. The method of line drawing as claimed in claim 6, further comprising providing first dedicated instructions used to select and start up said data storage and said line coordinate generation, and second dedicated instructions used to start up said data storage and said line coordinate generation without selection thereof.

8. A method of line drawing, comprising the steps of:

fixing a line processing time for up to a specific number of pixels, and setting the line processing time to a value proportional to the number of pixels which have been processed upon said specific number of pixels being exceeded.

9. A method of operating a graphics computer comprising the steps of:

reading binary data of plural pixels;

storing multivalue patterns, each of which comprises plural multivalue data for one pixel; and

selecting multivalue data, corresponding to the read binary data for plural pixels, from said stored multivalue patterns.

10. The method of operating a graphics computer as claimed in claim 9, further comprising the steps of judging the position to start writing of pixel data according to an address of pixel data to be written in a frame buffer;

and writing pixel data in the frame buffer according to said start position for writing.

11. A method of operating a graphics computer comprising the steps of:

reading binary data of plural pixels;

storing mask patterns to mask specified pixel data for plural pixels;

selecting a specified mask pattern from said mask patterns to process the specified pixel data for read plural pixels; and

executing a mask processing according to the selected mask pattern.

12. The method of operating a graphics computer as claimed in claim 11, further comprising the step of judging the position to start writing of pixel data according to an address of the pixel data to be written in a frame buffer.

13. A method of operating a graphics computer comprising the steps of:

judging a position to start writing pixel data according to an address of pixel data to be written in a frame buffer; and

writing pixel data in the frame buffer according to said start position for writing.

14. A method of operating a graphics computer comprising the steps of:

storing binary pixel data;

reading binary data for plural pixels;

storing multivalue patterns, each of which comprises plural multivalue data for one pixel;

selecting stored multivalue data corresponding to read binary data for plural pixels and displaying stored pixel data.

15. The method of operating a graphics computer as claimed in claim 14, further comprising the steps of judging a position to start writing pixel data according to an address of pixel data to be stored and controlling the selection according to a judging result.

16. A method of operating a graphics computer having a graphics processor and a display, comprising the steps of:

storing binary pixel data;

reading binary data for plural pixels;

storing mask patterns used to mask specified pixel data for plural pixels;

selecting a specified mask pattern from said mask patterns to process specified pixel data for read plural pixels;

executing a mask processing using said selected mask pattern;

storing the processed pixel data; and

displaying the stored pixel data.

17. The method of operating a graphics computer as claimed in claim 16, further comprising the steps of judging a position to start writing of pixel data according to an address of pixel data to be stored, and according to a judging result.

18. A method of operating a microcomputer comprising the steps of:

computing data to be displayed on a raster scanning-type display unit in a CPU;

reading binary data of plural pixels, storing multivalue patterns, each of which includes plural multivalue data for one pixel, and

selecting multivalue data, corresponding to the binary data from read plural pixels, from said stored multivalue patterns;

carrying addresses to specify a destination of said data stored in a first address bus connected to said CPU;

storing said data in a memory connected to a second address bus;

storing address conversion data set by said CPU in registers; and

converting addresses received from the first address bus and outputting them to the second address bus.

19. A method of operating a microcomputer, comprising the steps of:

computing, at a central processing unit (CPU), data to be displayed on a raster scanning-type display unit;

generating information to select a draw method from an absolute value of a difference between start and end coordinates of a subject line to obtain input information using a selected draw method;

storing vector data at an address corresponding to the absolute value of a difference between the start and end coordinates of a subject line;

generating equations and constance to generate a line from the start and end coordinates, and

drawing a fixed area for stored vector data;

carrying addresses to specify a destination of said data in a first address bus connected to said CPU;

storing said data in a memory connected to a second address bus;

storing address conversion data set by said CPU in a plurality of registers; and

converting addresses received from the first address bus and outputting converted addresses to the second address bus.

20. A method of operating a microcomputer comprising the steps of:

computing data to be displayed on a raster scanning-type display unit in a CPU;

fixing a line processing time for up to a specific number of pixels, and

setting the line processing time to a value proportional to the number of pixels which have been processed in response to said specific number of pixels being exceeded;

carrying addresses to specify a destination of said data in a first address bus connected to said CPU;

storing said data in a memory connected to a second address bus;

storing address conversion data set by said CPU registers; and

converting addresses received from the first address bus and outputting them to the second address bus.

21. A method of operating a microcomputer comprising the steps of:

computing data to be displayed on a raster scanning-type display unit in a CPU;

reading binary data of plural pixels,

storing multivalue patterns, each of which comprises plural multi value data for one pixel,

selecting multivalue data, corresponding to read binary data for plural pixels from said stored multivalue pattern, and

judging the position to start writing of pixel data according to an address of pixel data to be written in a frame buffer according to said start position for writing;

carrying addresses to specify a destination of said data in a first address bus connected to said CPU;

storing said data in a memory connected to a second address bus;

storing address conversion data set by said CPU in a plurality of registers; and

converting addresses received from the first address bus and outputting them to the second address bus.

22. A method of operating a microcomputer, comprising the steps of:

computing, at a central processing unit (CPU), data to be displayed on a raster scanning type display unit;

carrying addresses to specify a destination of said data in a first address bus connected to said CPU;

storing said data in a memory connected to a second address bus;

storing address conversion information specifying an address conversion mode set by said CPU in a register; and

converting, at an address converter, addresses received from the first address bus and outputting converted addresses to the second address bus in accordance with the address conversion mode set by said CPU, wherein the address conversion mode is executed such that said addresses are arranged sequentially in two-dimensions in a plurality of blocks having a smaller area than the display, and wherein a size of each of said plurality of blocks is determined by said register.

23. The method of operating a microcomputer as claimed in claim 22, wherein said address converter is provided with first information that specifies an area in said memory to convert addresses according to address conversion information stored in said register, and to convert addresses generated on the first address bus according to said first information.

24. The method of operating a microcomputer as claimed in claim 23 wherein said address converter is provided with second information used to obtain a first field of a XS bit from a lower part of an address according to address conversion information stored in said register and third information used to distinguish a second field of a YS bit from a third field, and the exchange the second and third fields to convert addresses.

25. The method of operating a microcomputer as claimed in claim 24 wherein said address converter exchanges the second and third fields by operating on an address received from said first address bus according to said first information.

26. The method of operating a microcomputer as claimed in claim 22, wherein said address converter is provided with second information used to obtain a first field of a XS bit from a lower part of an address according to address conversion information stored in said register and third information used to distinguish a second field of a YS bit from a third field, and to exchange the second and third fields to convert addresses.