JPS61123874A - Graphic display unit - 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 B) Industrial Application Field The present invention relates to a graphic display device in which pixel data corresponding to each pixel on a display screen is composed of multiple bits, and is particularly capable of determining one color or shade. Regarding the same device.

(B) Prior Art Generally, in a graphic display device, pixel data corresponding to each pixel on a display screen is composed of a plurality of bits, for example, color data is composed of three bits of RlG and B. This color data is stored in three graphic memories for each of R, G, and B. In such a graphic display device, when changing the color of a displayed image, in other words, it is necessary to perform a painting process.
When checking a color or a pattern, it is necessary to determine whether the color data stored in the graphic memory is the same as the specified color or not.

However, as shown in the rPc-100 Technical Manual, only one memory was accessed at a time when printing from the graphics memory. In other words, when determining the color, R, G, B
Each graphics memory was accessed once, and the resulting data was processed by software.

(c) Problems to be solved by the invention In the conventional technology, it is necessary to access the graphic memory as many times as the number of bits that make up the color data, which has the problem of slowing down the processing speed. .

Moreover, the burden of software was also large.

(2) Means for Solving the Problems The present invention provides a register for setting specified n-bit pixel data, and a same-bit output of m-bit parallel data read from n graphic memories respectively. m pieces of n-bit comparators that input one n-bit input terminal and input the contents of the excitation register to the other n-bit input terminal, compare the input n-bit data, and output a match signal. It was established.

(e) Effect In the present invention, when color data corresponding to a specified color is set in a register and n graphic memories are accessed at once, m n-bit comparators are filled with data corresponding to m pixels. Each color data is inputted and compared with the specified color data.

Then, when both color data match, a match signal is output. Therefore, the output of the n-bit comparator is
By importing the color into the PU and checking it, it becomes possible to determine whether the color is the specified color or not.

(1), (2), and 13) are R, G, and B, respectively.
(4) is a CPU that reads 8 pits of data in one access, (5) is an address decoder that sends chip select signals C8I to C83 to each graphic memory, and (6) is a CPU that reads 8 pits of data in one access. A read/write control circuit controls data writing and reading, (7) is a color register for setting designated 3-bit color data, and (8a) to (8h) are inputs for each of the 3 pits. This is a 3-bit comparator that has terminals 1,000 and B, compares data input manually to both input terminals, and outputs a "1" level match signal from output terminal Y if they match, and input terminal B is the color register (7
), and the input terminal A is connected to the same bit output terminal of each graphic memo IJ (1) (2) +31. Specifically, the 3-bit comparator may be constructed of, for example, three exclusive OR gates and one NOR gate to which the gate output is input.

In addition, the decoder (5) provides three different addresses from CI)U(41) so that the CPU (4) can independently access the three graphic memos;+(11(2)(3)). , chip select signals C8I, C82
, C83 independently, and simultaneously (generates) all chip select signals C81 to C83 for a specific address from the CPU (4).
It is configured so that three graphic memo months 1) to (3) can be accessed at the same time.

Therefore, the color data corresponding to the color specified by the light bench, keyboard, or program is transferred to the data bus.
When the CPU (4) sets the color register (7) via the BUS, generates a specific address from the CPU (4), and outputs a read command, the three graphic memories (
1) to (3) are supplied with a read enable signal RE from a read/write control circuit (6), and are supplied with a read enable signal RE from a decoder (5).
) chip select signals C8I to C83 are given from
Eight pits of parallel data are read from each graphic memory. Then, each bit output of the successively output parallel 8-bit data is output from 3-bit comparators (8a) to (
8h) K are each input. That is, the graphics memory (
1) Eight color data corresponding to pixels ag1 to pixel 8, which were independently stored in -+31, are input to 3-bit comparators (8a) to (8h), respectively, and compared with designated color data. Therefore, the output data DO-D7 of the 3-bit comparators (8a) to (8h) is taken into the register (9), and the CPU
By checking the contents of the 8 pits in step (4), it can be determined whether the colors of the first to eighth pixels are the designated colors.

Thereafter, by incrementing the addresses given to the graphic memories (1) to (3), it becomes possible to determine the color of each pixel of the displayed image.

Incidentally, although the above description has been made regarding the determination of color, the determination of light and shade is also completely the same.

(g) Effects of the Invention According to the present invention, by accessing the graphic memory once, it can be determined whether the color or shading of a displayed pixel is the same as a specified color or shading. The speed is faster and the burden on the software is reduced.

[Brief explanation of drawings]

The drawing is a block diagram showing an embodiment of the invention. Views of main books (1)-(3)...Graphic memory, (4)-
...CPU. (Power...color register, (8a) to (8h)...3-bit comparator.

Claims (1)

[Claims] (1) Pixel data corresponding to each pixel on the display screen is n(n
: an integer of 2 or more) bits, each storing 1 bit of each pixel data constituting a display image, and m (m: an integer) bits in one access from the graphic memory. C to read parallel data
In a graphic display device equipped with a PU, a register for setting specified n-bit pixel data, and the same bit output of the n pieces of m-bit parallel data each read from the graphic memory are stored in one register. m pieces of n-bit comparators are provided for inputting data to a bit input terminal, inputting the contents of the register to the other n-bit input terminal, comparing the inputted n-bit data, and outputting a match signal. A graphic display device with special features.