JPH07261974A - Display control system - Google Patents

Abstract

PURPOSE:To simplify font data transfer and to reduce the burdens an a computer by providing a display storage means, a character data storage means and a control means for transferring font data stored in the character data storage means to the display storage means. CONSTITUTION:A CPU 10 issues a BITBLT command from a font ROM 16 to a frame memory(FRM) 12 for characters to be displayed to a CRT controller(CRTC) 15. Then, the CRTC 15 performs the BITBLT of the font data from the font ROM 16 to the FRM 12. At the time, since the font ROM 16 and the FRM 12 are connected by a local graphic bus 17 and the font data are not passed through a system bus 18, the font data are transferred without influencing the system bus 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention enables high-speed display of characters on a display such as a computer system,
The present invention relates to a display control system that improves system performance.

[0002]

2. Description of the Related Art Conventionally, in a display control system for displaying characters on a display such as a computer system, a microcomputer (hereinafter referred to as CPU) for controlling the entire computer system displays the characters from a font ROM in which font data is stored. A CR that controls the drawing timing on the FRM and the display timing on the display in order to read the font data of the character and write the font data to the frame memory (hereinafter referred to as FRM) that stores the image data of the character to be displayed.
Font R on the T controller (CRTC)
By sending the font data read from OM,
It is designed to display characters. Also, all these data exchanges are performed via the system bus. This CRTC is a bit block transfer (hereinafter referred to as BIT) that transfers in block units in FRM.
BLT), straight line drawing, rectangle drawing, and the like.

[0003]

However, in the conventional display control system, since the CPU has to read font data from the font ROM and write the data into the CRTC, the CPU for displaying characters is required. However, there is a problem in that the load on the computer is heavy and the transfer capability of the system bus becomes a bottleneck, resulting in deterioration of character display performance and system performance.

[0004]

A display control system according to the present invention includes a display storage unit for storing display data to be displayed on the display unit and a character for storing character font data in the same format as the display storage unit. The data storage means and the control means for transferring the font data stored in the character data storage means to the display storage means are provided.

[0005]

In the present invention, the display storage means stores the display data to be displayed on the display means, the character data storage means stores the font data of the character in the same format as the display storage means, and the control means controls the characters. The font data stored in the data storage means is transferred to the display storage means.

[0006]

【Example】

Example 1. FIG. 1 is a block diagram showing a configuration of a display control system of the present invention, and FIG. 2 is an explanatory diagram for explaining a method of storing font data in a font ROM. In the figure, 10 is a microcomputer that controls the entire system (hereinafter referred to as CPU), 11 is a main memory, 12 is a frame memory (hereinafter referred to as FRM) that stores image data such as characters to be displayed, and 13 is output from the FRM 12. Digital pixel data converted to analog RGB
RAMDAC incorporating a look-up table and a DA converter for converting into a signal and outputting to the CRT 14.
Is.

Numeral 15 indicates drawing on the FRM 12 and CRT1
A CRT controller (hereinafter referred to as a CRTC) for controlling the display timing to 4 and a font ROM 16 for storing font data. As shown in FIG. 2, the font ROM 16 stores the font data in the FRM 12 image data. Is the same as.

Here, the FRM 12, CRTC 15 and font ROM 16 are the local graphics bus 1
7, the data is exchanged between the FRM 12, the CRTC 15, and the font ROM 16 via the local graphics bus 17 without using the system bus 18.

Next, a method of storing image data of the FRM 12 and a method of storing font data in the font ROM 16 of this embodiment will be described. For example, CR
When the display of T14 is 1024 × 768 dots and 256 colors are displayed, the FRM 12 has a configuration of 1 Mbyte, X direction = 1024 pixels, Y direction = 1024 pixels, and 8 bits / pixel. Further, here, Y direction = 1024 pixels, but this is because of the configuration of the memory used for the FRM 12, and Y direction = 76.
Parts other than 8 pixels are not displayed, Y direction = 7
It may be 68 pixels.

The font ROM 16 is the FRM 12
, X direction = 1024 pixels, Y direction = 819
2 pixels, 1 bit / pixel, 24 ×
The 24-dot font data and the 16 × 16-dot font data are stored as shown in FIG. As a result, the data storage methods of the FRM 12 and the font ROM 16 become the same, and the FRM that is the function of the CRTC 15
By using the BITBLT function for performing block-by-block transfer within 12, by designating the X coordinate and the Y coordinate corresponding to the character to be displayed on the CRT 14 in the CRTC 15, as in the BITLT within the FRM 12,
It is possible to perform block transfer in character units from the font ROM 16 to the FRM 12.

Next, the operation of transferring font data to the FRM 12 will be described. First, the CPU 10 is a CRT
Font ROM for characters to be displayed for C15
Issue a BITBLT command from 16 to FRM 12. Then, the CRTC 15 receives the input BITBLT.
Font ROM1 based on the command, font data
BITBLT from 6 to FRM12. At this time, since the font ROM 16 and the FRM 12 are connected by the local graphics bus 17, the font data does not pass through the system bus 18, so that the system bus 18 is not affected. It becomes possible to transfer font data.

The CPU 10 also controls the X coordinate and Y in the font ROM 16 corresponding to the characters to be displayed on the CRT 14.
Simply specify the coordinates and the font data for that character will be F
Since it can be transferred to the RM 12, the font data is read from the font ROM 16 in the CPU 10 and C
There is no need to write to RTC15, CP
The load on U10 is reduced, and the character display performance and system performance can be improved.

Example 2. In this embodiment, the method of storing font data in the font ROM 16 of the first embodiment is FRM1.
The data storage method is different from the data storage method of No. 2, and other configurations are the same as those of the first embodiment. FIG. 3 is an explanatory diagram for explaining a method of storing font data in the font ROM 16 of this embodiment. As shown in FIG. 3, the font data of the character is assigned by the font ROM address, and the font data can be read by designating the address.
In addition, the storage method shown in FIG.
This embodiment uses a font ROM having the same configuration as that of the first embodiment and storing font data as in the conventional case.

In the case of this embodiment, a CRT is used as in the first embodiment.
It is not possible to transfer font data to FRM12 using the BITBLT function of C15.
The font transfer command is newly extended to C15. This font transfer command is given to the CRTC in order to perform the operation of reading the font data from the font ROM and writing it to the FRM, which was performed by the CPU in the prior art.

Therefore, in this embodiment, the CPU 10 is C
The font ROM 16 used in the first embodiment is added to the RTC 15.
Instead of designating the XY coordinates, the font address of the font ROM 16 is designated, and by the font transfer command, the CRTC 15 reads the font data of the designated font address and transfers it to the FRM 12.

As described above, the CPU 10 has the CRTC 15
Since the CRTC 15 transfers the font data from the font ROM 16 to the FRM 12 simply by giving the font address to the CPU 10, the load on the CPU 10 is reduced, and the character display performance and the system performance can be improved.
Data exchange from the font ROM 16 to the FRM 12 is performed via the local graphics bus 17 as in the first embodiment, and the system bus 18 is used.
It is possible to transfer font data without affecting the.

[0017]

As described above, according to the present invention, the display storage means stores the display data to be displayed on the display means, and the character data storage means stores the character font data in the same format as the display storage means. Since the font data stored in the character data storage means is transferred to the display storage means by the control means, the font data can be transferred by transferring the data between the same storage formats. This simplifies the process and reduces the load on the computer system.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a display control system of the present invention.

FIG. 2 is an explanatory diagram illustrating a method of storing font data in a font ROM.

FIG. 3 is an explanatory diagram illustrating a method of storing font data in a font ROM according to the second embodiment.

[Explanation of symbols]

 12 frame memory (display storage means) 14 CRT (display means) 15 CRT controller (control means) 16 font ROM (character data storage means) 17 local graphics bus (dedicated bus)

Claims (5)

[Claims] 1. A display storage means for storing display data to be displayed on the display means, a character data storage means for storing character font data in the same format as the display storage means, and a storage for the character data storage means. And a control means for transferring the generated font data to the display storage means. 2. When the block transfer instruction is input, the control means transfers the font data stored in the character data storage means to the display storage means based on the block transfer instruction. The display control system according to claim 1, wherein: 3. A display storage unit for storing display data to be displayed on the display unit, a character data storage unit for storing character font data for each font address, and a font stored in the character data storage unit. A display control system comprising: control means for transferring data to the display storage means in accordance with the storage format. 4. When the font address is input, the control means reads font data corresponding to the font address from the character data storage means, and the font data is adjusted to the display control means according to the storage format. 4. The display control system according to claim 3, wherein the display control system is for transfer. 5. The character data storage means and the display storage means are connected by a dedicated bus, and the font data stored in the character data storage means is transferred via the dedicated bus. And claim 1, claim 2, claim 3 or claim 4
Display control system described.