Advanced Micro Devices Corporation

Chung-Li Yu

Shinkyo Kaku

Edward T Pak

Ho-Ming Leung

David R Staab

George W Li

Vinod Menon

Greg W Barr

Koichi Kagawa

Anan Nagarajan

Shabbir M Latif

Steven Gary

Occurrence of uncorrectable errors in a stored sector of data which includes a data block, an error checking and correcting (ECC) block and an error detecting (CRC) block is detected. ECC logic is connected to a data bus and responsive to the ECC block in the sector, for generating an error polynomial identifying a location and a value for correctable errors in the sector. CRC logic is connected to the data bus and responsive to the CRC block in the sector for generating a syndrome identifying detected errors in the data block. An evaluation logic circuit is included that is coupled to the ECC logic and the CRC logic and responsive to the error polynomial and the syndrome for generating an uncorrectable error signal if the detected errors do not match the correctable errors. The error checking and correcting code is a Reed-Solomon code as in the X3B11 standard. Likewise the CRC code is a Reed-Solomon code as in the X3B11 standard. The evaluation logic implements a reverse CRC generation polynomial having a plurality of terms in the same order as the error polynomial. Detection logic receives the plurality of terms of the error polynomial, generates an estimated CRC syndrome based on the reverse CRC generation polynomial, and generates the uncorrectable error signal if the estimated CRC syndrome is not equal to the generated CRC syndrome.

Comparison of an estimated CRC syndrome to a generated CRC syndrome in

An apparatus for rotating bit-mapped data includes a specially designed data array (9) that includes a normal port (10) for accessing horizontal words of data and a rotated port (15) for accessing vertical words of data. In addition, address generating logic (6) is provided that automatically generates proper address seqences for accessing the normal words or the vertical words as appropriate during a rotation operation. The apparatus is cascadable (FIG. 29) to provide effectively any size data array.

Bit map rotation processor

ECC/CRC error detection and correction system

A device controls in real time the assembly of data for a bit map scanning device, such as a laser printer, under supervisory control of a host processor. The image data words are stored in a source memory and assembled in a video buffer, and automatically scanned out to the scanning device. The host processor generates a simplified set of control words that defines graphics, text and layout of the page to be assembled. A raster interface synchronizes the output of the assembled data with the scanning device. Three basic modes are supported: (1) dispatch mode, (2) font read/write mode, and (3) graphics load mode. The dispatch mode is the normal operational mode which provides for dispatching data from a source memory location to the video memory and for supplying data from the video memory out to the raster printer. The font read/write mode gives the host the ability to read/write font or graphics data from/to the source memory or the video memory. The graphics load mode provides for transfer of a bit mapped window data to the video memory from the processor. The video memory can be divided into two bands.

Apparatus for assembling data for supply to a scanning output device

A decoder receives a series of input words defining variable length facsimile codes and generates pixel data to form a facsimile of an image. A code windowing apparatus selects a variable length code from the received series of words. A decoding ROM generates intermediate codes and code window control signals in response to the selected variable length codes. A reference windowing apparatus connected to receive pixel data generated during the decode of a previous scan line of the facsimile, selects a reference window of pixel data from a previous scan line. A color change detector indentifies a position of a color change picture element in the reference window. Output pixel data is generated in response to the intermediate codes and the position of the color change picture element in the reference window.

Apparatus for decoding facsimile coded data to image data with coding

Binary image data is converted to CCITT standardized coded data by utilizing two barrel shift registers for selecting a window of image data from a reference line and from a coding line, two color changing detectors for converting the image data in a window to color changing codes, and one specially designed state machine for generating facsimile coded data from those color changing codes. The state machine operates on color change location data for the selected window to generate intermediate codes. The intermediate codes are then translated to an output format such as the CCITT standard.

Growing community of inventors

San Jose, CA, United States of America

Chung-Li Yu