# US 8,629,880 B2 · Two dimensional memory access controller

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- Number: US 8,629,880 B2
- Document ID: US8629880B2
- Status: Granted
- Kind: B2
- Application number: 13/557,495
- Filed: 2012-07-25
- Published: 2013-03-21
- Granted: 2014-01-14
- Earliest claimed: 2009-02-26
- Assignees: Presagis
- Applicants: Jim Jonas
- Inventors: Jim Jonas
- Web page: https://patentgrep.com/patent/US8629880B2

## CPC

- G09G 5/39: Control of the bit-mapped memory
- G06F 12/1441: {for a range}
- G06F 12/0207: {with multidimensional access, e.g. row/column, matrix}
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A memory control device is adapted to derive a two dimensional location on a graphic display surface from address signals of a graphics processing unit (GPU), and to compare the derived two dimensional location to a two dimensional range of authorized locations corresponding to a subset of the display surface; and to modify the address signals of the graphics processing unit (GPU) if the address signals do not fall within the two-dimensional range of authorized locations corresponding to a subset of the display surface, and to propagate the address signals unmodified to a display memory otherwise.

## Claims

### Claim 1

A memory control device adapted to:
derive a two dimensional location on a graphic display surface from address signals of a graphics processing unit (GPU);
compare the derived two dimensional location to a two dimensional range of authorized locations corresponding to a subset of the display surface; and
modify the address signals of the graphics processing unit (GPU) if the address signals do not fall within the two-dimensional range of authorized locations corresponding to a subset of the display surface, and to propagate the address signals unmodified to a display memory otherwise.

### Claim 2 (depends on 1)

The memory control device of claim 1, further adapted to re-direct a data value by modifying a value of the address signals.

### Claim 3 (depends on 1)

The memory control device of claim 1, adapted to modify the address signals of the GPU by operating logic disposed between the GPU and the display memory.

### Claim 4 (depends on 1)

The memory control device of claim 1, further adapted to identify the two dimensional range of authorized locations by a horizontal range and a vertical range.

### Claim 5 (depends on 4)

The memory control device of claim 4, further comprising:
the horizontal range comprising a plurality of values each corresponding to a column of the display, and the vertical range comprising a plurality of values each corresponding to a row of the display.

### Claim 6 (depends on 4)

The memory control device of claim 4, further adapted to set the horizontal range and the vertical range in increments.

### Claim 7 (depends on 1)

The memory control device of claim 1, further adapted to redirect addresses within a fixed refresh buffer address range to a current display buffer address range.

### Claim 8 (depends on 1)

The memory control device of claim 1, further adapted to redirect unauthorized READs to a fixed address range.

### Claim 9 (depends on 1)

The memory control device of claim 1, further adapted to redirect unauthorized WRITEs to a fixed address range.

### Claim 10

A memory controller comprising:
logic to intercept addresses between a graphics processing unit (GPU) and a display memory, and to modify values of unauthorized addresses but not modify values of authorized addresses;
wherein it is determined if the addresses are authorized addresses by deriving a two dimensional location on a graphics display from the addresses, and comparing the derived two dimensional location to a two dimensional range of authorized locations corresponding to a subset of the graphics display.

### Claim 11 (depends on 10)

The data processing system of claim 10, further comprising:
logic to pipeline the addresses and control signals.

### Claim 12 (depends on 10)

The data processing system of claim 10, further comprising:
logic to pass data directly between the GPU and the display memory.

### Claim 13 (depends on 10)

The data processing system of claim 10, further comprising:
logic to re-direct READ operations in a fixed range corresponding to a refresh buffer to one of multiple selectable frame buffers.