JPS59143192A - Scrol controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a scroll control device used in a display device for characters, graphics, etc. More specifically, the present invention relates to a scroll control device that enables scrolling functions to be realized independently on divided screens in a pit refresh type CRT display device that stores characters or figures in a display memory in a dot pattern. be.

[Description of prior art]

Conventionally, the scrolling function in a CRT display device rewrites all bits of the display memory, which has been achieved by changing the screen refresh start address. The former method has the drawback that the contents of the all-bit display memory must be rewritten many times until the desired displacement is reached, and a large amount of CPU time is occupied. Furthermore, although the latter method can perform scrolling (ri) relatively easily over the entire screen, scrolling in all directions independently of the split screen has drawbacks such as extremely complicated hardware.

[Object of the present invention]

The present invention has been made to solve these drawbacks in the prior art, and aims to realize a device that has a simple configuration and can arbitrarily and easily scroll split screens independently.

In the device according to the present invention, in the process of calculating the display memory address in focus units from the address in character units,
A horizontal scroll control memory that manages the number of rasters for each split screen and a vertical scroll control memory that manages the don't P in the order of split and both sides are provided, and by rewriting the contents of these control memories, the horizontal and This allows vertical scrolling.

[Description of Embodiments] FIG. 1 is a block diagram showing an example of a device according to the present invention. In this figure, a character address line number generation circuit 1 inputs a character clock and inputs ( 7 to generate a rask number, and also generate a character address via the character number register 6. These are stored in the pit display memory.
(not shown).
The current rask address is sent to the horizontal scroll control memory 5, and the rask number is sent to the adder 61. The horizontal scroll control memory 5 outputs a character start raster address Y representing the displacement from the display start point to the start rask position of the character frame indicated by the character address, and a dot displacement X from the left end of the split screen. The adder 61 adds the raster number indicating the actual display line in the display line from the line register 2 and the character start raster address Y to generate an actual raster address and sends this to the vertical scroll control memory 7.

This vertical scroll control memory 7 generates the cumulative number Z of dots at the position indicated by the actual raster address from the display start point when the split screens are arranged in order, and sends this to the adder/multiplier 62. Output. This cumulative number of dots Z(Ii, corresponds to the dot address at the left end of the split screen including the position indicated by the real raster address, and the adder 62 adds to 2 the number of dots from the left end of the split screen which is the output from the horizontal scroll control memory 5. Add the number of displaced dots
/ generates a file. Here, horizontal scroll control memory 5
and the sleep scroll control memory 7 are connected to the bus via load registers 41 and 42, respectively, and can be arbitrarily and independently rewritten, for example, a random access memory is used. The operation of the apparatus will be explained below with reference to FIGS. 2 to 7. In the following explanation, the character frame is 10 x 10 dots and the screen size is 80 dots x 4.
Assume that the first line of the character ``λ'''' is displayed at the first character position of the divided screen 6 in 0 raster and 5 divided screen directions. That is, FIG. 2 is an example of a correspondence diagram between the physical screen and character addresses in this case, and FIG. 6 is an example of a correspondence diagram between the physical screen and the divided screen. FIG. 4 is a diagram showing the structure of a character frame. The character address line number generation circuit 1 generates the character address 16. from FIG. 2 via each register 2, 3 for the display position of the character 11A I+. Line number (raster number) 0
are generated respectively.

FIG. 5 shows the contents of the horizontal scroll control memory 5 corresponding to the screen configurations shown in FIGS. 2 to 4. This horizontal scroll control memory 5 is
The number of ζ horizontal displacement dots X=O and the character start raster address Y-40 are output, respectively.

FIG. 6 shows a simple model (meaning) regarding the output of the horizontal scroll control memory 6, and each output X and Y is
It represents the values in the X-axis and Y-axis directions when the split screen is rearranged, and Y is unrelated to the width (length in the X direction) of the split screen. The output Y is added to the line number O output from the register 2 in an adder 61, and sent to the vertical scroll control memory 7 as a real raster address.

FIG. 7 shows the contents of this vertical scroll control memory 7. The vertical scroll control memory 7 is designated with the actual square address 40, and outputs the cumulative number of dots Z=1600 from the start of display as shown in FIG. This output Z is sent to the adder 62
At , it is added to the output X(-0) of the horizontal scroll control memory 5 to generate a real dot address of the bit display memory. Similarly, real dot addresses of the bit display memory for one screen are generated from all character addresses and line numbers. By cyclically changing the content of the horizontal scroll control memory 5 corresponding to the character address of the split screen 6, only the display area of the split screen 3 on the display screen is cyclically displaced character by character. Similarly, by cyclically changing the contents of the vertical scroll control memory 7 corresponding to the actual square address of the split screen 3, only the display area of the split screen 6 is cyclically displaced in units of squares. do.

[Effects of the present invention]

As explained above, the present invention provides a horizontal scroll control memory for managing the number of rasters and a vertical scroll control memory for managing the cumulative number of dots in the process of converting a character address into an actual dot address in the display memory. The scrolling function is realized by rewriting the control memory of the screen, and with a simple configuration, it is possible to arbitrarily and easily scroll the divided screens independently.

[Brief explanation of the drawing]

Fig. 1 is a configuration block diagram showing an example of a device according to the present invention, Fig. 2 is a correspondence diagram between a physical screen and character addresses, Fig. 5 is a correspondence diagram between a physical screen and a split screen, and Fig. 4 is a correspondence diagram of character frames. 5 is a diagram showing the contents of the horizontal scroll control memory corresponding to the screen configurations shown in FIGS. 2 to 4', FIG. 6 is a simplified model diagram regarding the output of the horizontal scroll control memory, and FIG. FIG. 3 is a diagram showing the contents of a vertical scroll control memory. 1...Character address line number generation circuit 2.
- Paraline number register, 3...Character number register, 41.42...Load register, 5...
Horizontal scroll control memory, 61, 62...adder,
7...Vertical scroll control memory, agent Shin Kuzuno - Figure 2, Figure 3, Figure 4, Figure f.

Claims (1)

[Claims] (1) In a bit refresh type CRT display device that stores characters or figures in a bit display memory in a dot pattern, the means for converting a character address into a bit unit address on the bit display memory is a rewritable memory. A horizontal scroll control memory that has the function of managing the number of rasters in units of split screens and converting the character address into the cumulative number of rasters from the display start point and the number of horizontal displacement dots from the left edge of the split screen, and a split screen with rewritable memory. and a vertical scroll control memory having a function of sequentially managing the number of dots and converting the number of divided screen rasters and the number of horizontally displaced dots into the cumulative number of dots from the starting point of the display screen, and rewriting each of the control memories. 1. A scroll control device characterized in that scrolling is performed in a horizontal direction and/or a vertical direction.