5.3. Signaling processors

Signaling processors belong to the class of specialized МP. They are developed for the solution of tasks of digital processing of signals, the examples of which are:

• filtration of signal;

• folding of two signals;

• calculation of values of cross-correlation function of two signals;

• calculation of autocorrelation function;

• direct-reverse transformation of Fourier’s integrals and others like that.

The tasks of digital processing are solved in the communication equipment and data transfer, tools of hydro- and radio-locations, medical equipment and robotics, engines control, in motor-car electronics, television, in the measuring technique and others like that.

The excellent feature of tasks of digital processing of signals is streaming character of processing of data large volumes in the real mode of time. Operation in real-time requires the increase of МP operating speed, and treatment of data large arrays − hardware tools of intensive exchange with peripheral devices.

High operating speed of signaling МP is arrived due to:

• to application of modified RISC-architecture;

− to the problem-oriented set of instructions, for example, to plugging in the set of instructions of such operations, as a multiplication with the accumulation of the MAC (С: = АхВ + С) with the marked number of implementations in a command in the cicle and with the rule of change of element indexes of arrays A and B;

− application of reduction methods of command cycle duration, for example conveyorization of commands;

• to placing of operands of most commands in registers;

• to the use of shadow registers for maintenance of the state of calculations during the context switching;

• to the presence of hardware multiplication which enables to execute the multiplication of two numbers for one command clock;

• to hardware support of programmatic cycles.

The signaling processors of different firms-producers are divided into two classes of processors: on the simple and cheap microprocessors of data processing in a format fixedpoint and on expensive microprocessors, that hardwarely support operations above data in a format with a floating comma.

Signaling fixedpoint processors. The first signaling processor ТМS320С10, worked out by a firm "Техаs Іnstruments" in 1982, processed fixedpoint numbers.

A processor is executed after Harvard architecture basis of which is distribution of access busses to built-in memory of the programs and data. It enables to carry out the selection of command and data in one computer cicle and provide implementation of most commands for one cycle.

The signaling processor ТМS320ХС5х consists of center processor (СР), built-in memory of the programs and data, multifunction peripheral units, that in most cases enable delivered from an additional external apparatus.

Signaling processors with a floating comma. The use of signaling processors for data processing in a format with floating point is predetermined by the row of tasks (integral transformations, algorithms of compression, decompression, adaptive filtration) which require high exactness of data presentation in a wide dynamic range. Operation with data in a format with a floating point simplifies and accelerates their processing, promotes program reliability, as does not require implementation of operations of rounding off and normalization of data, from hunting of situations of underflow and overflow. However hardware and cost expenses of such МP considerably more, than processors of data processing in a format with a fixedpoint.

The first representative of class of processors with a floating comma was МP of ТМS320С30.

A processor has a 32-bit bus of commands and data and 24-bit bus of address, contains 2 blocks of RAM in 1К of 32-bit words, 32-bit block of multiplication with a floating comma, cache memory of commands by a capacity 64, that has a 32-bit words, 8 registers for operations with the increased exactness, 2 generators of address and register file, will realize the different addressing modes. 40-bit ALD of processor operates both with integers and with numbers in a format with a floating comma. Built-in controller DMA enables to connect in time a calculation and exchange of data with memory. Presence in МP of ТМS320С30 of multiprocessor interface, two external interfaces and two serial ports, extended interrupt system simplifies constructing of the systems on its basis.

All operations in a processor are executed for one clock. A processor can in parallel execute in one clock the operation of multiplication and аrithmetic-logic operation with numbers in a format with the fixed or floating comma. A processor has a flexible set of instructions and support of HLL of С.