Coordinate Mapping Circuit With Demultiplexed Bit Channels
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Solution Overview
Problem
The existing graphics processing unit (GPU) circuit for mapping multi-dimensional texture coordinates to memory addresses is complex due to excessive shifting and multiplexing, particularly in the silicon footprint, which is inefficient and costly in terms of area and latency.
Innovation Solution
A circuit design that interleaves all coordinate bits together, including non-data bits, and then demultiplexes them into separate channels padded with null bits, reducing the need for shifting and multiplexing by aligning the channels through simple left and right shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the existing GPU circuit uses traditional shifting and multiplexing methods to map multi-dimensional texture coordinates to memory addresses, then the mapping function is achieved, but the silicon footprint and circuit complexity increase significantly
Solution Approach 1:
The patent segments the coordinate mapping process into distinct channels (e.g., 1-coordinate channel, 2-coordinate channel, 3-coordinate channel) that process different portions of the interleaved bit-string. Each channel handles specific coordinate combinations independently, reducing the need for complex multiplexing and shifting operations in a single unified circuit.
Solution Approach 2:
The patent transforms the coordinate representation by interleaving bits from multiple coordinates into a single bit-string, effectively changing from a multi-dimensional coordinate space to a one-dimensional address space. This dimensional transformation eliminates the need for complex shifting and multiplexing operations to combine multiple coordinate values.
2Reliability
If the existing GPU circuit performs extensive shifting operations to align coordinate bits, then the correct memory addresses are generated, but the latency increases
Solution Approach 1:
The patent performs preliminary interleaving of coordinate bits before they need to be processed into final memory addresses. By pre-organizing the bits in the correct interleaved sequence and routing them to appropriate channels, the circuit eliminates the need for time-consuming shifting operations during the address generation phase, thereby reducing latency while maintaining accuracy.
3Adaptability or versatility
If the circuit uses multiple multiplexers to select and combine coordinate bits, then the address generation is flexible, but the silicon area consumption increases
Solution Approach 1:
The patent divides the coordinate processing into separate channels that each handle specific coordinate combinations. This segmentation allows the circuit to use simple, dedicated logic paths for each channel rather than requiring large, complex multiplexers that can handle all coordinate combinations in a single unit, thereby reducing silicon area while maintaining flexibility.
Solution Approach 2:
The patent designs the channels to be multi-functional, where each channel can process different coordinate combinations based on the input pattern. This universality allows the circuit to handle various coordinate configurations without requiring separate dedicated hardware for each case, reducing overall silicon footprint while maintaining adaptability.
Data Source
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AI summary
A circuit for mapping N coordinates to a 1D space. The circuit: receives N input bit-strings representing respective coordinates, which can be of different sizes; produces a grouped bit-string therefrom, in which the bits, including non-data bits, are grouped into groups of bits originating from the same bit position per group; and demultiplexes this into n=1...N demultiplexed bit-strings, and sends each to a respective n-coordinate channel. The nth demultiplexed bit-string comprises: a respective part of the grouped bit-string that has n coordinate data bits and N-n non-data bits per group, and all other groups filled with null bits. Each but the N-coordinate channel comprises bit-packing circuitry which packs down the respective demultiplexed bit-string by removing the no-data bits, and removing the same number of bits per group from the null bit. The packed bit-strings are then aligned relative to one another according to the corresponding bit positions, and combined.