Optimizing Modems Using Code Composer Studio and TI Resources

nels to 48 per DSP. In fact, for the MSP MEDIA Gateway line of DSP resource boards based on C6000 DSPs, Commetrex undertook the four phases, and the process worked. Our MSP-320 PCI board, with two C6201 DSPs and a quad E1/T1 network interface, needed 48 to 60 channels of processing from each DSP. For many of the general telephony stream-processing tasks, the C6000 C optimizer gave us the densities we needed with no assembly coding. “Out-of-the-box”C-coded modems, which are a reference design and written for understandability rather than efficiency, might compile to, say, six simultaneous modems. You should be able to double that by guiding the modems through the Code Composer Studio (CCS) optimizer and by ensuring that your memory layout takes advantage of the C6000’s on-chip RAM. CCS includes an optimization tutorial that provides a recommended code development flow consisting of four phases (Figure 1). (A similar tutorial is in the TMS320C6000 Programmer’s Guide.) Phase 1 involves compiling and profiling your baseline C code. Before you begin any optimization effort, use the profiling tools to identify the performance-critical areas in your code. Phase 2 involves compiling with the appropriate optimization options and analyzing the feedback provided by the compiler to improve the performance of your code. Phase 3 is a critical phase during which you use a number of techniques to tune your C code for better performance. Phase 4 is needed if the performance of certain areas of your code must be improved beyond the tuning phase. After yet another profile of the code, you can extract the performance-critical areas and rewrite them in linear assembly language.