JPS6265172A - Control system for data coding and decoding - Google Patents

Abstract

PURPOSE:To attain the effective use of a memory and also to increase the processing speed of a central processing unit, by delivering continuously coding and decoding commands through the central processing unit as necessary. CONSTITUTION:A central processing unit secures a user buffer for storing coding data and also produces a coding command through a coding instruction issuing part 34. A starting part 35 receives a coding command and starts a coding/ decoding mechanism part 33. A coding processing part 36 carries out the coding operation and stores the coding result in a user buffer. A result state discriminating part 37 for coding process checks whether a space exists or not in a user buffer storing mode. If no space exists, an informing part 36 informs the matter to the central processing unit. The central processing unit secures a buffer again at a reprocessing part 40 and shifts the buffer to the part 34 for production of a coding command. The same procedure is carried out also in a decoding mode.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical field to which the invention pertains) The present invention relates to a data encoding/decoding control method for a display system having a data encoding/decoding mechanism.

(Prior Art) FIG. 3 is a diagram showing the hardware configuration of a display system having a conventional encoding/decoding mechanism.

In the figure, 1 is the main CPU on which the system's basic software (OS) and service programs run, 2 is the basic software, the central processing unit, and the main memory that stores the buffer area used by these software, and 3 is the image data storage. An encoding/decoding mechanism performs encoding/decoding; 4 is a graphic display processor that displays image data stored in the image memory on the screen; and 5 holds figures to be displayed on the screen as bit images. 6 is a main bus for exchanging data through communication between the main CPt1 and the graphic display processor, 7 is a display screen such as a CRT, and 8 is a secondary device such as a disk that stores files used by the central processing unit. It is a storage device.

FIG. 4 is a diagram showing a storage image of two-dimensional graphic information stored on the image memory, where 11 is two-dimensional graphic information;
12 is a bit-divided image in which two-dimensional graphic information is divided into bit information, and 13 is an image memory in which the bit-divided image 12 is developed.

In the bit division of the bit division image 12, significant points of the figure correspond to bit 1, and non-significant points (points where nothing is written) correspond to bit 0.

Further, the bit-divided image 12 is divided into bits with a width of 16 bits in the direction from left to right and from top to bottom, and expanded into a continuous memory area of 16-bit width on the image memory.

Two-dimensional graphic information 11 stored on the image memory is transferred and displayed on the screen in a bit-divided form by a bit-divided image 12.

In the display system shown in FIG. 3, the central processing unit reads image data stored in one image memory from the image memory 5 to the buffer memory of the central processing unit located on the main memory 2, and then transfers it to the secondary memory. Memory bag!
A service format is required in which image data is stored in 8 and displayed on one screen.

At this time, there is a method of transferring the image data on one image memory as is to the secondary storage device 8 and storing it, but since this method stores a large amount of bit data, when storing multiple image data, This puts pressure on the memory area on the secondary storage and causes problems for the service program to run.

FIG. 5 is an explanatory diagram showing a conventional encoding/decoding control flow.

For the reasons mentioned above, the display system is equipped with the encoding/decoding mechanism 3, and according to the control flow shown in FIG. 5, the image memory is compressed to save memory capacity and stored in the secondary storage device 8. It is designed to be stored in .

In FIG. 5, arrow 15 is the flow of transferring image data on the image memory to the encoding/decoding mechanism, arrow 16 is the flow of transferring encoded data to the buffer of the central processing unit, and arrow 17 is the flow of transferring the image data on the image memory to the encoding/decoding mechanism. 10 shows a flow of storing encoded data from a user program buffer into a secondary storage device.

The control flow for decoding encoded data on secondary storage is as follows:
Take the opposite direction to that shown in FIG.

FIG. 6 is a diagram showing a storage format of encoded data, and shows an example of data conversion for encoding a two-dimensional image on an image memory onto a buffer of a central processing unit.

In the figure, 20 is two-dimensional image data obtained by developing two-dimensional graphical information into a bit image, 21 is encoded data consisting of bit data after encoding each row of the two-dimensional image data 20, and 22 23 is the user buffer area secured by the central processing unit in the main memory, and 23 is the encoded bit data that is packed into the user buffer area 22 from left to right and from top to bottom. 24 shown in the shaded area is a bit string EOFB (End of Faccimill) indicating the end of the encoded data.
e Block), 25 is a PAD bit (PAD:
PADding).

The steps in the flow shown in FIG. 5 are as follows: (i) The central processing unit secures a user buffer for storing encoded data.

(ii) The central processing unit issues a command to the basic software (OS) to designate the image data on the image memory and store the encoded data in the user buffer area of (i).

(m) When the basic software (OS) receives this command, it starts the main CPUI (Figure 3), transfers the image data on the image memory to the encoding/decoding mechanism, and converts the data after encoding processing. Transfer to user buffer area.

Generally, the amount of data after encoding processing of image data depends on the bit expansion pattern of the image data to be encoded.
The buffer size for storing encoded data cannot be accurately predicted before processing.

Therefore, in the above flow (i), when the central processing unit specifies the size of the user buffer, since an accurate value cannot be predicted, the size is roughly estimated to be as large as the amount of data for one image.

Therefore, if the amount of data after encoding is smaller than the estimated size, the process will end normally, but if you specify a small buffer size to save the user buffer, the amount of data after encoding will be smaller than the estimated size. larger than the specified buffer size.

The instructions in the above flows (i), (it), and (iii) result in error processing, and it is necessary to secure a large buffer again in the central processing unit and repeat the above flows (i), (it), and (in). , which has the effect of delaying the processing time of the central processing unit.

As described above, the conventional method has the disadvantage that the processing time for encoding the data is slow due to the fact that the amount of data after encoding the image data is uncertain.

(Objective of the Invention) In order to solve these drawbacks, the present invention aims to provide a control method for encoding data or decoding encoded data with a single encoding command from a central processing unit. Its purpose is to achieve efficient memory usage on the central processing unit side and to improve the processing speed of the central processing unit.

(Structure of the Invention) In a display system having a control mechanism capable of encoding and decoding data, the present invention provides a first means for allocating a memory using a central processing unit and storing the result of encoding data in the memory. If the result of encoding the data is larger than the memory size, the system notifies the central processing unit that the storage area is insufficient, and the central processing unit again secures memory and stores the data. A second means for storing the encoded result in a memory, and performing the first or second means until all data is encoded, and storing the encoded result in a plurality of memories or one memory. and a means for decoding one data from a plurality of memories or one data encoded by the first, second, and third means. .

(Embodiment) FIG. 1 is an embodiment diagram showing a control system for processing during encoding according to the present invention, and shows a case where image data is taken as an example.

In the figure, 30 is a processing section in the central processing unit, 31 is an O8 section (basic software section), 32 is an encoding/decoding control section which is a part of the basic software section, and 33 is a section for encoding/decoding processing. 34 is a coding command issuing unit from the central processing unit; 35 is a startup unit that starts the coding/decoding mechanism; 36 is a coding processing unit; 37 is the result of the coding process. A status determination unit, 38 is a termination processing unit when the encoding process ends normally, 39 is a notification unit that notifies the central processing unit of the status of the encoding process, and 40 is a unit that secures a buffer for encoding again when there is a buffer shortage. This is a reprocessing unit that has a function of starting encoding processing.

The details of each functional block will be explained below.

■,. 34: The central processing unit reserves a user buffer to store the encoded data.

At this time, the size of the user buffer (U) is set as an initial value of 2/3 of the size since the amount of data after encoding cannot be accurately predicted.

Next, an encoding command (CP command) is issued to O8 using the following values as parameters.

(i) Address (assumed ADDR) and size U of the user buffer.

(it) The area where the image data to be encoded is stored (
IAREA).

■ Month 1] The 4 O8 receives the CP command and passes the parameters (i) and (ii) of ■ to the encoding/decoding control unit 32.

This control section sets these parameters in the encoding/decoding mechanism section 33 again and starts it up.

■The Kasasashin JA3U anal encoding/decoding mechanism section interprets the passed parameters and executes the following operations.

One row of image data is read from IAREA and encoded. The encoded data is divided into 16 bits and stored in the user buffer.

・”! 9 Result of digitization process Determining unit 37: Checks whether the user buffer is empty when storing the user buffer.

If there is space, the encoded data is stored, and if there is no space, the process moves to operation (3).

If data for one row of IAREA can be encoded and stored in the user buffer, the process moves to operation (2).

When the last line of IAREA can be encoded and stored in the user buffer, proceed to operation (2).

■After all the data in Faccimill IAREA is encoded, it is encoded as EOFB (End of Faccimill), which means the end of processing.
e Block) bit string (00000000000
000010000000000000001) is stored in the user buffer.

When storing EOF[], a PAD (Padding) bit string (consisting of 0 bits) is added to match the 16-bit width.

■If the user buffer area is insufficient even though the data to be compressed by 4 inches exists in the IAREA, the encoding/decoding control unit 32 will notify the user that there is a buffer shortage using the return value of the CP command. The central processing unit is notified as follows.

■Re-Go 11 The central processing unit that was notified of the buffer shortage error,
Allocate a buffer again and move on to the operation.

In this way, since the encoding function consists of the operations ① to ② above, the following control is possible.

(A) If the user buffer is larger than the amount of data after encoding, the process ends with - encoding commands.

(b) If the user buffer is smaller than the amount of data after encoding, it is possible to achieve the desired result by continuously issuing encoding commands between the central control unit and the OS until the encoding process is completed. Image data can be encoded. FIG. 2 is an embodiment diagram showing a control system for processing during decoding according to the present invention.

In the figure, 51 is a decoding instruction issuing unit from the central processing unit;
Reference numeral 2 denotes a starting unit that starts the encoding/decoding mechanism, 53 a decoding processing unit, 54 a decoding process result state determination unit, 55 a notification unit that notifies the central processing unit of the EOFB undetected state;
56 is a reprocessing unit that issues a decoding command again when EOFB is not detected.

A detailed explanation of each functional block is shown below.

@) dLl command 'Part 51: The central processing unit issues a decryption command (EX command) to O8 using the following values as parameters.

(i) Address and size of the user buffer that stores encoded data, (n) Area (OAR) that stores image data to be decoded.
EA).

■■ Unit 52: O8 receives the EX command and passes the parameters (i) and (ii) of ■ to the encoding/decoding control unit 32.

This control section sets these parameters in the encoding/decoding mechanism section again and activates it.

[Phase] Stealth<b * * s The hidden superencoding/decoding mechanism section interprets the passed parameters and executes the following operations.

Encoded data is read from the user buffer, and the data is set to 0AREA without being decoded.

■ Hi's ′
1. Unit 54: Check whether the encoded data read from the user buffer is EOFB.

If it is not EOFB, shift to [phase] operation.

When EOFB is detected, the decoding process is terminated and the central processing unit is notified of normal termination.

If EOFB is not detected and all encoded data in the user buffer has been processed, the process moves to operation @.

(2) The processing result that "A side" 4 EOFBs are not detected is notified to the central processing unit.

In this way, since the decoding function consists of the operations ① to 0 above, the following control is possible.

(C) If all the encoded data is stored in the first user buffer (stored up to EOFB), the process ends with - times of decoding commands.

(D) When the EOFB is not present in the user buffer, by continuously issuing decode commands between the central processing unit and the O8 until the EOFB is detected.

The desired encoded data can be expanded to a specified image area.

Using the encoding and decoding functions described above.

Encoding and decoding of image data of any size can be performed from the central processing unit.

(Effects of the Invention) As explained above, according to the present invention, it is possible to effectively encode and decode image data of any size from a central processing unit, and (1) central processing unit By continuously exchanging encoding commands between the encoding/decoding mechanism and the central processing unit, even if the user buffer becomes insufficient after encoding, it is possible to deal with it. The buffer within can be used efficiently.

(2) When the user buffer after encoding processing is insufficient,
Since there is no need to reissue the encoding command from the beginning, processing efficiency is improved and the encoding processing time is optimized.

This effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an embodiment diagram showing a control method for processing during encoding in the present invention, FIG. 2 is an embodiment diagram showing a control method for processing during decoding in the present invention, and FIG. 3 is a diagram showing a conventional method. Coding·
FIG. 1 is a diagram showing a hardware configuration of a display system having a decoding mechanism. Fig. 4 is a diagram showing a storage image of two-dimensional graphic information stored on the image memory, Fig. 5 is an explanatory diagram showing the conventional encoding/decoding control flow, and Fig. 6 is a diagram showing the storage image of two-dimensional graphic information stored on the image memory. FIG. 3 is a diagram showing a storage format. 1...Main CPU, 2...Main memory, 3.
... Encoding/decoding mechanism, 4... Graphic display processor, 5... Image memory,
6... Main bus, 7... Display screen such as CRT, 8... Secondary storage device, 11... Two-dimensional graphic information, 12... Bit divided image, 13... Image memory. 15... Transfer flow from image memory to encoding/decoding mechanism, 16... Transfer flow of encoded data to user buffer, 17... Transfer flow from user buffer to secondary storage device, 20 ...Two-dimensional image data, 21... Encoded data, 22... User buffer area, 23... Encoded bit data, 24... EOFB (End of Faccimi)
lle Block), 25...PAD bit, 30
. . . Processing part, 31 . Part, 35... Starting part, 36
... Encoding processing unit, 37... Encoding process result state determination unit, 38... Termination processing unit, 39... Notification unit. 40... Reprocessing unit, 51... Decryption instruction issuing unit, 5
2... Starting section, 53... Decryption processing section, 54...
Decoding process result status determination unit, 55... notification unit, 56
...Reprocessing department. Patent applicant: Nippon Telegraph and Telephone Corporation Figure 1 Figure 2 Figure 3 Figure 5

Claims (1)

[Scope of Claim] A display system having a control mechanism capable of encoding and decoding data, comprising a first means for allocating a memory by a central processing unit and storing a result of encoding the data in the memory; When the encoded result becomes larger than the memory size, the system notifies the central processing unit that the storage area is insufficient, and the central processing unit secures memory again and encodes the data. a second means for storing the result in a memory; and one or both of the first and second means until all the data is encoded, and the encoded result is stored in one or more memories. and a means for decoding data encoded by the first, second, and third means into one data from a plurality of memories or from one memory. -Decoding control method.