Data compression and decompression

A decompression unit configured to decompress compressed data, the compressed data representing an n-bit decompressed data value, the compressed data comprising a first compressed subset of bits and a second compressed subset of bits, the first compressed subset representing the n−2 most significant bits of the uncompressed data value and the second compressed subset representing the two least significant bits of the uncompressed data value, the decompression unit comprising:

• a first decompression module configured to implement a first decompression scheme to decompress the first compressed subset to determine the n−2 most significant bits of the decompressed data value;
• a second decompression module configured to implement a second decompression scheme to decompress the second compressed subset to determine the two least significant bits of the decompressed data value, wherein the first and second decompression schemes are different;
• and
• combining logic configured to combine the determined n−2 most significant bits of the decompressed data value and the determined two least significant bits of the decompressed data value to determine the n-bit decompressed data value,
• wherein the compressed data uses five bits to represent the two least significant bits of four decompressed data values, wherein four of the five bits comprise the second least significant bit of each decompressed data value and one of the five bits is indicative of a least significant bit for each of the four decompressed data values.

A non-transitory computer readable storage medium having stored thereon an integrated circuit definition dataset that, when processed in an integrated circuit manufacturing system, configures the integrated circuit manufacturing system to manufacture a decompression unit which is configured to decompress compressed data, the compressed data representing an n-bit decompressed data value, the compressed data comprising a first compressed subset of bits and a second compressed subset of bits, the first compressed subset representing the n−2 most significant bits of the uncompressed data value and the second compressed subset representing the two least significant bits of the uncompressed data value, wherein the decompression unit comprises:

• a first decompression module configured to implement a first decompression scheme to decompress the first compressed subset to determine the n−2 most significant bits of the decompressed data value;
• a second decompression module configured to implement a second decompression scheme to decompress the second compressed subset to determine the two least significant bits of the decompressed data value, wherein the first and second decompression schemes are different;
• and
• combining logic configured to combine the determined n−2 most significant bits of the decompressed data value and the determined two least significant bits of the decompressed data value to determine the n-bit decompressed data value,
• wherein the compressed data uses five bits to represent the two least significant bits of four decompressed data values, wherein four of the five bits comprise the second least significant bit of each decompressed data value and one of the five bits is indicative of a least significant bit for each of the four decompressed data values.