JPS62293338A - How to control virtual image memory - Google Patents

Abstract

PURPOSE:To perform the memory control capable of the reduction of the memory capacity by reusing a memory cell is printed and used in a virtual memory system. CONSTITUTION:A cell address table CAT is provided for the control of both virtual memories M1 and M2 together with the queue CAQ of an idle memory cell. It is supposed that the 1st page of a form is printed with the maximum NXM dots and this form is divided into (nxm) sections. Then the dot pattern data of each section is stored in a cell memory and these data are written and read for each cell memory. While the cell memory to which the dot pattern data is not written yet forms a queue CAQ and is written by obtaining the address of the dead cell memory form the CAQ. Then the cell memory to which data are written writes its address to the corresponding address of the table CAT. The reading of the data is carried out with reference to the CAT and the read data are sent to a printer. The memory cells containing the printed and undesired data are juxtaposed in the CAQ. These used cell memories are still available again and therefore the desired memory capacity can be reduced.

Description

Detailed Description of the Invention] 3. Detailed Description of the Invention [Summary] After the first page has been developed, the second page is developed at the same time as the first page is printed. At this time, in order to use the memory freed by printing for immediate expansion, 1. ;] Two pages are controlled by the page's worth of memory.

[Industrial application field]

The present invention relates to a virtual image memory control method, and is intended to reduce the capacity of print data storage memory.

[Conventional technology]

To print an image on paper, a memory that stores dot pattern data representing the image is used, and the memory (Ml
1 page of data is written to the 2nd page), and then read out and printed by the printer while writing the next page of data to the 2nd page.
The following method is used: write data into a memory (designated M2), then read and print from memory M2, write data for the next page into memory M1 during this time, and repeat this process.

The required memory capacity is at least two pages, and the memory (M1 or M2) cannot be used for writing and reading at the same time, so the next page cannot be developed (written) until printing (reading) is finished.

[Problem that the invention seeks to solve]

Whether the image is text or graphics, if delicate printing is to be performed, the number of dots will increase and the memory capacity will increase. The fact that the large-capacity memory is required for two or more pages is also a problem in terms of cost.

However, the present invention seeks to provide a memory control method that can reduce memory capacity.

[Means for solving problems]

As shown in FIG.
A cell address tape CAT and a queue CAQ of empty memory cells are provided for managing the memory cells. Maximum N for 1 page of paper
Assuming that xM dots are to be printed, this paper is divided into nxm sections (the number of dots in one section is NM/nm), the dot pattern data for each section is stored in a cell memory, and writing and reading are performed using this cell memory as a unit. Let's do it.

A cell memory to which no dot pattern data has been written has a CAQ created, the address of an empty memory cell is known from the CAQ, and writing is performed to that memory cell, and the cell memory to which data has been written uses that address as the corresponding address in CAT (the corresponding address). If the data is for the first section on the paper, it is written to the i address). Reading is performed with reference to CAT, and the read data is sent to the printer. Cell memories (empty cell memories) containing data that are no longer needed after being read and printed are arranged in the CAQ.

[Effect]

In this way, the cell memory that has been printed and is no longer used can be immediately reused, so that the required memory capacity can be reduced. Even though printing is performed after writing data for one page, and writing is considerably faster than reading (printing), the total capacity of memories M1 and M2 is sufficient for 1.5 pages.

FIG. 3 shows the procedure for writing dot pattern data of a certain section (x, y) on a sheet of paper into a cell memory.

First, find the CAT number (address of each area of CAT), which corresponds to the number of the above section, so y-n+x
It is expressed as If this number exceeds NM/nm, there is no corresponding classification and printing is not possible. If printing is possible, has the cell memory been allocated? In other words, is it in CAT? If not, one free cell memory (the one pointed to by the pointer) is taken out from CAQ, its address is set in CAT, and pattern data is written into the cell memory.

For printing, have you already allocated the cell memory as shown in Figure 4? If YES, read the cell memory and pass the read data to the printer.
and release it from CAT. If such an operation is repeated for the number of sections for one page (4096 in this example), data writing for one page is completed.

Since the density of dots is constant, whether printing is possible or not is determined by the paper size. Therefore, as shown in Fig. 2, check whether the area is printable (within MXN dots) or not.
If so, by instructing CAT to prohibit cell memory allocation, efficient memory usage can be achieved. Next, examples will be shown.

〔Example〕

Each position on the paper is represented by X and Y coordinates, which are the fifth
As shown in Figure ta, the left shoulder is the origin, the right direction is the positive direction of the X axis, and the downward direction is the positive direction of the Y axis.In this example, the side in the X direction is represented by 4096 dots, and the side in the Y direction is Assume that there are 4096 pieces. Then, (as shown in bl, the sides in the X and Y directions are divided into 64 parts, and one page is divided into 64 dots x
There are 4096 cells in 64 rectangular sections (cells). The image data to be printed on paper is handled in units of rectangular divisions (cells) as described above, and the memory that stores the data of the cells (cell memo January address is stored in the table CAT in C1 in the same figure (C1). By looking at the cell data, you can know whether the cell data is stored in the real memory (-1! memory) or not, and if so, what is its address.The cell memory that stores the cell data is stored in the cell address queue CAQ. The managed and free cell memory address is CA
Create a queue on Q.

A collection of cell memories constitutes a screen memory, and image data (dot patterns) of rectangular sections on the paper are developed in the cell memory by a write operation to the memory. No cell memory is allocated to rectangular sections that are not written to. When the contents of the cell memory become unnecessary and are cleared by printing, the cell memory is registered in the CAQ. The writing is
It learns free cell memory from CAQ and performs operations on it.

When printing starts, an empty cell memory is generated, and writing can be performed to the empty cell memory, and reading for printing and writing to the empty cell memory can be performed in parallel. However, it is not possible to write and read data into the same memory at the same time, and the memory for writing and the memory for reading are separated as shown in M1 and M2 in FIG. However, this memory Ml.

M2 does not need to have real memory for one page each. Even if you start printing after writing one page's worth of data to memory, the memory to which you start writing after printing starts is
Since the memory cells released upon completion of printing can be used, one page is not necessary. Further, since no cell memory is allocated to a section of paper without image data, even if one page is initially written, the memory capacity may be less than one page. Furthermore, if printing is started with a certain amount of data (less than one page) stored in the memory, the memory capacity can be further reduced.

FIG. 6 is a diagram for explaining writing, and FIG. 7 is a diagram for explaining printing. At the time of writing, the empty cell memory pointed to by the CAQ pointer is targeted for writing, and the cell address is written in the address position corresponding to the writing position of CA and T (the above rectangle), and the allocation is set to the state. After this process, C
The AQ pointer is advanced by one (pop-down). Empty cell memories marked with diagonal lines in FIG. 2 are removed from CA and Q.

Next, when the cell memory is released by printing, the address is stored in CAQ (shown with diagonal lines in Figure 3).
It is made ready for writing. The CAQ pointer pops up.

The table CAT stores the address of the cell memory that stores the data of one section of the paper divided into 64×64 sheets, and the contents of one cell are as shown in FIG. 9(d). That is, the 16-bit ( 1 word) and its O to 11
The bit indicates the address of the cell memory on the screen memory (however, the 9 pins of the offset from the memory block are omitted), and the remaining 4 bits are for control data, one of which is for the allocation flag, and the other one is for the allocation flag. One is for prohibition of allocation. The capacity of the cell memory is 64x64 bits, or 512 bytes.

This coordinate space is shown in FIG. Take the word horizontally,
■Since the word is 2-by-i, 4 words are lined up horizontally,
64 words are arranged vertically.

〔Effect of the invention〕

As explained above, the present invention employs a virtual memory system so that printed and used cell memory cards are immediately reused, so that memory capacity can be reduced, which is effective in reducing costs.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the memory control method of the present invention, FIGS. 2 and 3 are flowcharts explaining writing, FIG. 4 is a flowchart explaining reading, and FIG. 5 is a detailed explanatory diagram of the present invention. 6 and 7 are explanatory diagrams of CAQ, FIG. 8 is an explanatory diagram of cell memory, and FIG. 9 is an explanatory diagram of CAT. In FIG. 1, CM is a cell memory, CAT is a cell address table, and CAQ is a cell address queue.

Claims (1)

[Claims] A sheet of paper is divided vertically and horizontally, dot pattern data for each division is stored in a cell memory (actual memory), and the addresses of the cell memory in which the data is stored are stored in correspondence with the addresses of the divisions. Using a table (CAT) to manage empty cell memories and a cell address queue (CAQ) to manage empty cell memories, the cell memories storing the data are read out and printed, and the empty cell memories are arranged in the cell address queue. The writing of the dot pattern data of each section is characterized in that an empty cell memory is found from the cell address queue and the cell memory is written to the corresponding cell, and the cell memory freed by printing is immediately used for writing the dot pattern data. How to control virtual image memory.