System and method for memory access

• US 9,852,092 B2
• Filed: 03/28/2014
• Issued: 12/26/2017
• Est. Priority Date: 03/28/2014
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Leijten, Jeroen
• Primary Examiner(s): Huson, Zachary K
• Application Number:
  US14/228,475
• Publication Number:
  US 20150278132A1
• Time in Patent Office: 1,369 Days
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: G06F 2209/482 Application
• CPC Class Codes: G06F 2209/5016 Session
• CPC Class Codes: G06F 9/4843 by program, e.g. task dispatcher, supervisor, operating system
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G09G 2360/127 Updating a frame memory using a transfer of data from a source area to a destination area
• CPC Class Codes: G09G 5/39 Control of the bit-mapped memory
• CPC Class Codes: G09G 5/393 Arrangements for updating the contents of the bit-mapped memory
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence

Abstract

A memory controller performs DMA operations on arbitrary sized elements unbounded by the word size of the host memory or processor, which performs operations based on an element that represents an atomic data unit such as a pixel. In this manner, a corresponding coding effort is not concerned with computing and locating word boundaries and accommodating unused bits of data conventionally used for accommodating word boundaries on pixel data for video rendering, for example. An element in memory corresponds to a rendered atomic data item, such as a pixel. The controller determines an element precision indicative of a size of the element, and identifies a unit of memory based on a memory location and a packed representation of a plurality of the elements relative to the memory location. The unit has a height and width, defining elements arranged in a grid, and an element position is based on coordinates.

Claims

1. A method of accessing memory, comprising:

identifying an element, the element corresponding to a rendered atomic data item;

determining an element precision indicative of a size of the element;

identifying a unit of memory based on a memory location and a packed representation of a plurality of the elements relative to the memory location, the unit of memory resides in a region of memory such that each row of the width represents contiguous memory and each column represents a stride offset from a consecutive row of the column;

iteratively referencing a plurality of elements based on a position in the unit of memory, the position specified based on a coordinate of the element in the unit of memory independently of a memory location in which the element resides;

moving the referenced elements to a destination;

identifying a portion of the elements outside the region, the region defined by an origin designated by a grid position of an element; and

augmenting the elements in the identified portion.

2. The method of claim 1 wherein the unit of memory has a height and width, the height and width defining a plurality of elements arranged in a grid.

3. The method of claim 1 wherein the packed representation defines a height and width of a plurality of elements, the unit of memory having a fixed number of elements along the height and width.

4. The method of claim 1 further comprising iteratively referencing an element based on the size of the element and a grid position in the unit of memory without reference to a word boundary of the element.

5. The method of claim 1 further comprising augmenting the elements outside the region by replacing a value of the augmented element with a constant.

6. The method of claim 1 further comprising augmenting the elements outside the region by replacing a value of the augmented element with the value of the element preceding the augmented element.

7. The method of claim 1 further comprising augmenting the elements outside the region by copying values from elements in corresponding positions within the region.

8. The method of claim 1 wherein an origin and a width defines the region, the elements outside the region being either to the left or right, further comprising augmenting the elements on either the right or the left of the region.

9. The method of claim 1 wherein the destination comprises a rendering device for displaying the unit of memory on a pixelated form, the destination retaining the height and width of the unit of memory.

10. The method of claim 9 wherein the rendering device comprises a video display/capture buffer.

11. The method of claim 1 wherein the precision of the element is different than a word size of a memory storing the unit of memory.

12. The method of claim 1 wherein the packed representation preserves an ordering of element values in a work by shifting bits adjacent to a preceding element stored in a same word.

13. A direct memory access (DMA) controller, comprising:

a plurality of elements, each element corresponding to a rendered atomic data item, each element having an element precision indicative of a size of the element;

a unit of memory, the unit of memory based on a memory location and a packed representation of a plurality of the elements relative to the memory location;

the unit of memory having a height and width defined by coordinates for iteratively referencing a plurality of elements based on a position in the unit of memory, the position specified based on a coordinate of the element in the unit of memory independently of a memory location in which the element resides;

at least one instruction for moving the referenced elements to a destination, the instruction configured for referencing an element when the precision of the element is different than a word size of a memory storing the unit of memory; and

a command distributor configured to;

identify a portion of the elements outside a region, the region defined by an origin designated by a grid position of an element; and

augment the elements in the identified portion.

14. The DMA controller of claim 13 wherein the packed representation defines a height and width of a plurality of elements arranged in a grid, the unit of memory having a fixed number of elements along the height and width.

15. The DMA controller of claim 14 wherein the unit of memory is configured for referencing an element based on the size of the element and a grid position in the unit of memory without reference to a word boundary of the element.

16. The DMA controller of claim 13 wherein the destination comprises a rendering device for displaying the unit of memory on a pixelated form, the destination retaining the height and width of the unit of memory.

17. The method of claim 16 wherein the rendering device comprises a video display/capture buffer.

18. A computer program product having instructions encoded on a non-transitory computer readable storage medium that, when executed by a system, cause the system to:

identify an element, the element corresponding to a rendered atomic data item;

determine an element precision indicative of a size of the element;

identify a unit of memory based on a memory location and a packed representation of a plurality of the elements relative to the memory location, the unit of memory resides in a region of memory such that each row of the width represents contiguous memory and each column represents a stride offset from a consecutive row of the column;

iteratively reference a plurality of elements based on a position in the unit of memory, the position specified based on a coordinate of the element in the unit of memory independently of a memory location in which the element resides;

move the referenced elements to a destination;

identify a portion of the elements outside the region, the region defined by an origin designated by a grid position of an element; and

augment the elements in the identified portion.

19. The computer program product of claim 18 wherein the destination comprises a rendering device for displaying the unit of memory on a pixelated form, the destination retaining the height and width of the unit of memory.

20. The computer program product of claim 19 wherein the rendering device comprises a video display/capture buffer.