Arm Multicore Platforms Printer Jpeg High-speed Decoding Engine Design And Realization

The majority of PCL printer drivers will convert the files that are being printed (including graphics and texts) into jpeg files, then send the jpeg files to the printer. This is because it will reduce the data that needs to be transferred to the printer and also greatly simplifies the development of the printer driver. Inside the printer, the JPEG files will be decoded into BMP files for further processing. The work of decoding JPEG files takes above half of the CPU time on a printer which works in such a way, so JPEG decoding engine is one of the cores of the printer device, and improving the JPEG decoding speed is important for the performance enhancement of the printer.And JPEG decoding is a CPU-bound job, to improve the speed there is two ways: one is getting a more effective algorithm, the other is using more powerful CPU to do the calculation. In the embeded environment with single CPU, JPEG decoding speed already nearly achieves the limit and it is difficult to have the promotion space. But recently the appearance of the embeded multi-core system provides the possibility for promoting the performance.This pager is based upon the Linux platform with ARM11 MPCore (4 core) processor, it designs and realizes a high-speed JPEG decoding engine for the PCL XL printer control language. The primary coverage is as follows:Analyzes and decodes the PCL XL files, then picks up JPEG files from them. Parallelizes the decoding of the JPEG file on embedded multi-core platform, and do optimizations on memory reading etc according to the characteristics of the very system.Designs and implements the multi-thread job dispatching algorithm based on multi-core system.Analyzes and summarizes the performance improvement compared to the single core system.Additionally, this paper briefly introduces ARM(SIMD) instruction sets and some concepts of insert-assembly and hardware.