JPS6180288A - Image 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 [Field of Industrial Application] The present invention relates to an improvement in the write processing of an image display device that performs data filling to an image memory in units of word boundaries.

[Conventional technology]

Conventionally, when configuring an image memory in an image display device, addresses are often allocated using word boundaries in units of 8 bits, 16 bits, etc.

In an image display device having such an image memory, the image memory can only be accessed in one word boundary unit, that is, in units of 8 bits or 16 bits. For this reason,
In the write process, if you do not want to write just one bit at the top of the image memory, the CPU reads that word fr from the image memory, performs a partial fill process, and then writes it back to the image memory. It's a waste if you don't include it.

This has caused a problem in that writing processing takes a long time.

[Problem that the invention seeks to solve]

The present invention has been made in order to eliminate the above-mentioned problems, and an object of the present invention is to realize an image display device that can perform pit-by-pit writing to an image memory at high speed.

[Means for solving problems]

The present invention provides storage means that stores information corresponding to one bit of an image memory and is provided in the same number as the number of bits that are accessed at one time to the image memory, and a storage means provided for each of the storage means. a write control circuit that controls writing to the corresponding storage means, and a mask that is generally erased for each of the write control means and in which write prohibition information instructing the corresponding write control means to prohibit writing is set. The image display device is characterized in that the image display device is equipped with a register, sets write inhibit information in the mask register, and writes to the image memory in bit units.

〔Example〕

The present invention will be explained below with reference to the drawings.

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

In FIG. 1, 10 is an image memory, 20 is a display control section, 30 is a display, 40 is a storage means, 50 is a write control circuit, 60 is a mask register, 70 is an address register, and 80 is a processor.

The image memory 10 stores images to be displayed on the display 30. One pixel of the stored image corresponds to one bit of the image memory 10.

The display control unit 20 reads the contents of the image memory 10 and controls the display on the display 10.

The storage means 40 stores the same number of bits as the number of bits that the processor 80 accesses to the image memory 10 at one time, for example, 8 (4
0o to 40. ) is provided. Each storage means 40o~
40. The following information corresponding to one bit of the image memory 10 is stored. The correspondence between the contents of the storage means 408 to 407 and the image memory 10 is as shown in FIG.

The write control circuit 50 is provided for each storage means 40o to 407 from 50o to 507, and these control circuits control writing to the corresponding storage means.

The mask register 60 is connected to each of the control circuits 508 to 50 . It is provided for each. These mask registers 608-60. Input inhibition information is set to instruct the corresponding write control means to prohibit writing.

The address registers 70 are 70o to 70. Each storage means 40o to 40. It is provided for each. These address registers 708 to 707 are set with addresses on the image memory 10 where pixel information is to be written for the corresponding storage means.

Processor 80 sets write inhibit information in mask registers 60o to 60° and controls the entire device.

[Effect]

Next, the operation of such an image display device will be explained.

Words A, B, and C shown in FIG. 3(a) are
) The case of shifting by n bits so that the state shown in ) will be explained.

First, as shown in FIG. 4, only the word Ail pit is ROTATEd. In word A, the n bits from the left end are Atr, the other parts are Atr,
shall be. Let the word that has undergone this process be A.

Next, this word A is stored in the storage means 40o-407. A write inhibit signal is given to the storage means storing the information of part e in word A. This signal is applied by the processor 80 to the mask registers 608 to 60.
．． This is done by setting write prohibition information to the part corresponding to the e part.

Here, when writing is performed on the image memory 10, writing is performed only on portion f in FIG. 3(b). As a result, the data in part g in FIG. 3(b) is preserved. When writing word C, the mask register 6 is set so that writing to part h in FIG. 3(b) is prohibited.
0o~60. Set.

FIG. 5 is a block diagram of another embodiment of the image display device according to the present invention. In FIG. 5, the same parts as in FIG. 1 are given the same reference numerals.

In FIG. 5, 90 is an X register. The information set in the X register 90 is changed depending on the bit for which writing is to be prohibited, and the logic obtained by decoding this information is sent to the mask registers 608-60. Writing is performed in the image memory 1o bit by bit.

In the embodiment, a case has been described in which the image memo IJ 10 is accessed in units of 8 bits, but it may be accessed in units of other bits, such as units of 16 bits.

〔effect〕

According to such an image display device, the following effects can be obtained.

Information is stored in the storage means 40o to 407 in pixel units, and in the write process, write prohibition information can be given to each storage means 40o to 40°. by this,
When writing into the image memory 10 bit by bit, there is no need to take the trouble to read data from the image memory 1o. Therefore, bit-by-bit writing to the image memory 10 can be performed at high speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of an embodiment of the image display device according to the present invention, FIG. 2 is a diagram showing the correspondence between the storage means in FIG. 1 and the contents of the image memory, and FIGS. 3 and 4 are FIG. 1 is an explanatory diagram of the operation of the apparatus, and FIG. 5 is a block diagram of another embodiment of the image display apparatus according to the present invention. 10... Image memory, 40.408-407... Storage means, 50, 50o-507... Write control circuit, 60.608-607... Mask register.

Claims (1)

[Scope of Claims] Storage means that stores information corresponding to one bit of the image memory and is provided in the same number as the number of bits that are accessed at one time to the image memory; a write control circuit that controls writing to the corresponding storage means, and write prohibition information that is provided for each of the write control means and that instructs the corresponding write control means to prohibit writing. 1. An image display device comprising: a mask register, wherein write prohibition information is set in the mask register, and writing is performed in bit units to an image memory.