JPH04139529A - Graphic display device - Google Patents

Abstract

PURPOSE:To attain a high speed memory access for each unit data by taking the data out of a display memory and writing these data for each line when a logical arithmetic operation is carried out between two rectangular areas of the display memory. CONSTITUTION:The data on a horizontal line set in a 1st rectangular area are read into a line memory 1 and the data on a horizontal line set in a 2nd rectangular area corresponding to the 1st rectangular area are read into a line memory 2 respectively in each corresponding memory cycle. Then the data fetched into both memories 1 and 2 are turned into each desired form and then taken out through an ALU 4. Then the data equivalent to one horizontal line are continuously written in the same way as that set in a read mode. Thus the memory access time can be extremely increased for each unit data.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a graphic display device.

[Conventional technology]

A conventional graphic display device has two sets of registers 11 that store data read from two rectangular areas, as shown in FIG.
．． 12 and barrel shifter 13.
It has 14 (denoted as LU). Reading data into each register and writing data after a logical operation takes one memory cycle each, and the display memory 16
By storing the transfer source and transfer destination area data read out in the registers 11 and 12, respectively, and writing the logical operation data to the display memory 16 again, and repeating these operations,
Logical operations were performed between rectangular areas.

[Problem to be solved by the invention]

The conventional graphic display device described above executes and terminates a memory cycle each time data is loaded into each register and rewritten to the display memory, so the performance of logic operations between rectangular areas can be accelerated. The problem is that it is impossible.

[Means to solve the problem]

The graphic display device of the present invention is a graphic display device capable of bitmap display, and includes two sets of line memories capable of storing information of at least one scan line, a barrel shifter for shifting the output of the line memory, and the line memory. and a means for performing a logical operation with the output of the barrel shifter and writing it into the display memory, and when performing a logical operation between two rectangular areas on the display memory, retrieving and writing data from the display memory. It is characterized by being performed line by line.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. Line memory 1 and line memory 2 are each 128X1
This is an 8-bit FIFO memory. barrel shifter 3
has a built-in 16-bit register, and can latch the 16-bit output data from line memory 2, and regards the value of this built-in register and the output from line memory 2 as continuous 32 bits, It is possible to output 16 bits shifted by an arbitrary number of bits from this 32 bit data. Further, the ALU 4 performs a logical operation (for example, an AND operation) on the 16-bit data from the line memory 1 and the 16-bit data from the barrel shifter 3, and outputs the result to the display memory 6 via the data bus 5. The data bus 5 is a 16-bit wide data bus, and reads data from the display memory 6 and stores data from the ALU 4 in the display memory 6. The display memory 6 is a bitmap memory for displaying binary image information with a capacity of 2048 bits horizontally x 1024 bits vertically.
One physical memory address is given for 6 bits, and data input/output is performed using these 16 bits as one unit. At this time, the display memory 6 is composed of a dedicated dynamic type dual port memory, and the memory addresses are continuous in the horizontal direction. The data in the display memory 6 is sequentially read out and displayed on the CRTT.

Next, a case will be described in which a logical operation is performed between the first rectangular area and another second rectangular area on the display memory 6, and the result is stored in the second rectangular area. In this case, data on one horizontal line on the first rectangular area is stored in the line memory
Further, the data on one horizontal line on the second rectangular area corresponding thereto is read into the line memory 2 in one memory cycle to which each belongs. This type of dynamic dual-port memory has access modes such as nibble mode and page mode that speed up continuous access to consecutive or very close addresses. Access can be made very fast. Also, in this way, line memory 1
The data taken into the line memory 2 is processed into a desired form and taken out from the ALU 4, and data for one horizontal line is continuously written in the same way as when reading.

〔Effect of the invention〕

As explained above, the present invention uses two sets of line memories capable of storing information of one scan line or more, and stores data of one horizontal line in a rectangular area of a transfer source and a transfer destination for each line using consecutive memory cycles. The memory access time per unit of data can be reduced because it can be loaded into memory, and data for one horizontal line in the transfer destination rectangular area can be stored using consecutive memory cycles using the data taken into two sets of line memories. This has the effect of speeding up the process.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional example. 1.2... Line memory, 3... Barrel shifter, 4
...ALU, 5...Data bus, 6...Display memory, 7...CRT.

Claims (1)

[Claims] 1. A graphic display device capable of displaying a bitmap, 2.
A graphic display device comprising: a pair of line memories; a barrel shifter for shifting the output of the line memory; and means for performing a logical operation on the outputs of the line memory and the barrel shifter and writing the result to a display memory. 2. The graphic display device according to claim 1, wherein the line memory is capable of storing information of at least one scan line or more. 3. The graphic display device according to claim 1, wherein when performing a logical operation between rectangular areas on the display memory, data is taken out and written from the display memory on a line-by-line basis.