JP3254795B2 - Display screen scroll control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display screen scroll control device for scrolling a display screen such as a CRT display or a liquid crystal display.

[0002]

2. Description of the Related Art In a game machine or the like, the background screen may change for each of various scenes. In such a case, the display screen may be switched by scrolling each time the scene is changed. Also, a scrolling technique is used when a plurality of screens are continuously moved.

Conventionally, in order to realize such scrolling of the display screen, for example, as shown in FIG. 10, a display area in a VRAM space is moved by sequentially shifting a display start address IA of an image memory (VRAM). Let it be done. FIG. 10A shows a normal scroll mode in which the same page is repeatedly scrolled, and FIG. 10B shows a multiple page scroll mode in which a plurality of pages are scrolled. When scrolling a plurality of pages, image information for the number of pages displayed by scrolling needs to be stored in an image memory in advance in order to smoothly perform scrolling.

[0004]

However, since the number of screens to be displayed differs depending on the software to be used, when an image memory for a large number of screens is provided to accommodate all the software, the capacity of the image memory is reduced. There is a problem that it becomes enormous.

The present invention has been made to solve such a problem, and it is possible to perform scroll control with an image memory having a capacity of one screen regardless of the number of display screen pages to be scrolled. It is an object of the present invention to provide a display control device capable of scrolling a display screen.

[0006]

According to the present invention, there is provided an image memory for storing a pattern name of a plurality of regions constituting one display screen in correspondence with each of the plurality of regions, and a display start address for the image memory. Display start address supply means for supplying and updating the display start address sequentially during scrolling, and image memory address supply means for supplying the read address of the image memory to the image memory while sequentially updating the read address using the display start address as an initial value. A page address supply means for supplying a page address of a display screen and updating the page address when a read address supplied from the image memory address supply means reaches a final address of the image memory; The display pattern of the area is stored for a plurality of screens and the A removable pattern generator that inputs a pattern name output from an image memory and a page address output from the page address supply unit as an address and outputs a specified pattern of a specified page; It is characterized by.

[0007]

According to the present invention, the image memory does not store the data of the display screen itself, but stores the pattern name of each area when the display screen is divided into a plurality of areas. Is stored as a pattern for each area in the pattern generator. The displayed pattern is specified by the page address and the pattern name of each area, and is read from the pattern generator.

At the time of scrolling, the display area is moved by sequentially updating the display start address for the image memory. At this time, the display screen may extend over two pages. In this case, only the page address for the pattern generator is updated, and the pattern name stored in the image memory is not changed. Therefore, only the pattern names for one screen need be stored in the image memory, and the pattern names may be repeatedly read during scrolling. Even if the pattern name read from the image memory is the same, if the page number is different, a different pattern is read from the pattern generator, so that the display screen corresponding to each page is read, and scrolling of a plurality of pages is realized. Will be.

According to the present invention, the number of display screens can be determined by a detachable pattern generator, and only one display screen data needs to be stored in the image memory at all times. It is possible to flexibly deal with various software and reduce the capacity of the image memory.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a display device according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a main part of the display device. This device comprises a CPU 1 for controlling the entire system, and a CPU 1
The display control circuit 3 controls the display of the CRT display 2 under the control of the display control circuit 3 and a pattern generator (ROM table) 4 accessed by the display control circuit 3 to output a display pattern. Display control circuit 3
Are provided with two registers 11 and 12. The register 11 is used to set a display start address IA of the VRAM 15 to be described later, and constitutes a display start address supply unit together with a rewriting function of the CPU 1. The register 12 is for setting a display start page address IPA for specifying a page to be displayed.

The display start address IA set in the register 11 is supplied to the full adder 13. The full adder 13 adds the vertical display position information VD supplied from the timing generator 14 and the display start address IA set in the register 11, and adds the addition result to VD.
It is supplied as an upper address of the RAM 15. Horizontal display position information HD supplied from the timing generator 14
Are supplied as lower addresses of the VRAM 15. The full adder 13 and the timing generator 14 constitute an image memory address supply unit.

The VRAM 15 is an image memory, and stores a pattern name of each area in one display screen in association with each area. In other words, the display screen of one page is divided into a plurality of areas A of, for example, 8 × 8 dots as shown in FIG. As shown in FIG. 3, a pattern name PN # of, for example, 8 bits that specifies a dot pattern displayed in each area A is stored in the VRAM 15 in association with each area A. Pattern name PN # output from VRAM 15
Are supplied as lower addresses of the pattern generator 4.

On the other hand, the display start page address IPA set in the register 12 is supplied to the half adder 16. The half adder 16 constitutes a page address supply means together with the register 12.
Is added to the display start page address IPA supplied from the full adder 13 and the carry bit CB of the full adder 13. This addition output is supplied to one input of the multiplexer 17 as a page address PA2 for a multiple page scroll mode. The other input of the multiplexer 17 is
The page address PA1 for normal scrolling (output IPA of the register 12) is supplied. The multiplexer 17 selects one of the page addresses PA1 and PA2 based on the scroll mode switching bit PAOD. The page address PA output from the multiplexer 17 is supplied as an upper address of the pattern generator 4.

As shown in FIG. 4, the pattern generator 4 stores an 8 × 8 dot pattern of each area A of each page. The pattern generator 4 includes, for example, a ROM including a 3-bit page address PA, a 3-bit base address BA, and an 8-bit pattern name PN #.
Based on the address, a dot pattern on a designated page and in a designated area is output. This pattern generator 4 is mounted on, for example, an IC socket or the like,
It is detachable from the display control circuit 3 by a method such as being incorporated in an IC card. Thereby, it is possible to select according to the software to be used.

The dot pattern read from the pattern generator 4 is converted into RG
After being converted into each display color of B and converted into an analog signal by the DA converter 19, it is supplied to the CRT display 2 for display.

Next, the operation of the display device configured as described above will be described. First, during normal display operation,
“0” is set as the display start address IA in the register 11, and the page address IPA of the currently displayed page is set in the register 12. The timing generator 14 sequentially outputs the number VD of vertical display lines, and sequentially outputs the number HD of horizontal display dots while the number VD of vertical display lines is incremented by one. In response, the designated pattern name PN # is sequentially read from the VRAM 15. The register 11 has "0"
Is set, the carry bit CB is not output from the full adder 13, and the page address PA does not change. Therefore, from the pattern generator 4,
The pattern from the area (0, 0) to the area (63, 31) of the page specified by the page address PA is read, and one display screen is displayed on the CRT display 2.

Next, the scroll operation of the display screen will be described. FIG. 5 is a flowchart showing a control flow in a normal scroll mode for scrolling one display screen. First, during normal scrolling, the scroll mode switching bit PAOD is set to "0", and the multiplexer 17 is set to the selection mode of the page address PA1 (S1). Next, the display start page address IPA is set in the register 12 (S2), and the display start address IA is set in the register 11 (S3). Then, the timer is operated for a fixed time according to the scroll speed to perform the display operation (S4), and the display start address IA is updated (S5). The display for a fixed time (S4) and the update of the display address IA (S5) are repeated until the scroll stops. As a result, as shown in FIG.
Normal scrolling of the page specified by A1 becomes possible.

FIG. 7 is a flowchart showing the operation at the time of scrolling a plurality of pages. First, the scroll mode switching bit PAOD is set to “1” and the multiplexer 17
In the selection mode of the page address PA2 (S1
1). Next, the display start page address IP is stored in the register 12.
A is set (S12), and the display start address IA is set in the register 11 (S13). Then, the timer is operated for a fixed time according to the scroll speed to perform the display operation (S14), and the display start address IA is updated (S15). In this mode, when the addition result of the vertical display position information VD output from the timing generator 14 and the display start address IA overflows, the carry bit CB is supplied to the half adder 16.
The displayed page address PA2 is incremented, and the displayed page is switched. As a result, as shown in FIG. 8, the display screen of the next page appears continuously.
Display for a fixed time (S14) and update of display address IA (S
15) is repeated until the scroll is stopped. In this process, if the display start address IA exceeds the maximum value of the address of the VRAM 15 (S16), the display start page address IPA is updated (S17). As a result, the display screen of the next page appears continuously. VR
The pattern name PN # read from the AM 15 is simply read repeatedly even when the page is switched.

As described above, according to this display device, even when a plurality of pages are scrolled, the VRAM 15 stores
It suffices to store data for one display screen.
Capacity can be reduced. When changing the pattern to be displayed, the pattern generator 4 may be replaced. In the above example, the pattern stored in the pattern generator 4 is 64 × 3 for each page.
There are two patterns, but this is just the maximum,
6 as the pattern of each page of the pattern generator 4
It is not necessary to store all 4 × 32 patterns.

For example, the display screen shown in FIG.
It is composed of three pattern areas of 1, P2 and P3. The display screen shown in FIG. 9B is configured by two pattern areas P4 and P5. Assuming that the display screen shown in FIG. 9A is page 0 and the display screen shown in FIG. 9B is page 1, there are six types of patterns # 1 to # 6 for each page as shown in FIG. Prepare VRAM
If the pattern names are stored in the form shown in FIG. 9C in FIG. 15, the display screens of page 0 and page 1 can be created with only six patterns each. Thus, the storage capacity of the pattern generator 4 can be significantly reduced. Although this example is a very simple example, in general, the capacity of the pattern generator 4 is reduced by performing an operation of aggregating areas having a common combination of patterns into the same pattern name throughout the entire display screen. be able to.

It is needless to say that other means such as a counter may be used as a means for generating the address of the image memory or the page.

[0022]

As described above, according to the present invention,
The pattern of the display screen can be determined by a detachable pattern generator.
Since it is only necessary to store the data for the display screen, it is possible to flexibly cope with various software having different numbers of displays and to reduce the capacity of the image memory.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a display screen and a divided area in the same device.

FIG. 3 is a diagram showing data stored in a VRAM in the same device.

FIG. 4 is a diagram showing a configuration of a pattern generator in the apparatus.

FIG. 5 is a flowchart showing an operation in a normal scroll mode in the apparatus.

FIG. 6 is a diagram for explaining an operation of the normal scroll.

FIG. 7 is a flowchart showing an operation of a multi-page scroll mode in the apparatus.

FIG. 8 is a diagram for explaining an operation in the multiple-page scroll mode.

FIG. 9 is a diagram for explaining a pattern registration method of a pattern generator in the apparatus.

FIG. 10 is a diagram for explaining a conventional scroll method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CPU, 2 ... CRT display, 3 ... Display control circuit, 4 ... Pattern generator, 11 and 12 ... Register, 13 ... Full adder, 14 ... Timing generator, 15 ... VRAM, 16 ... Half adder, 17 ... Multiplexer, 18 ... Color Palette, 19 ... DA converter.

Claims (1)

(57) [Claims] 1. An image memory storing a pattern name of an area corresponding to each of a plurality of areas constituting one display screen, a display start address being supplied to the image memory, and the display start when scrolling. Display start address supply means for sequentially updating addresses; image memory address supply means for supplying the image memory while sequentially updating the read address of the image memory with the display start address as an initial value; and displaying the page address of the display screen. A page address supply unit for updating the page address when the read address supplied from the image memory address supply unit reaches the final address of the image memory; and a display pattern for each area of the display screen for a plurality of screens. Stored and output from the image memory A display screen, comprising: a detachable pattern generator that inputs a turn name and a page address output from the page address supply means as an address and outputs a specified pattern of a specified page. Scroll control device.