Does anyone know which microcontroller is suitable and cheap for caryying 'add and multiply' instruction per cycle?
Also how can I work the precise time per instruction cycle out? For example I want a processor to complete the process such as a large number of 'add and multiply' instructions within 4 seconds.
I think MSP430 from TI is exactly what you need. They are prety cheap and some versions have a hardware 16x16->32 multiply/accumulate unit (as a memory-mapped peripheral).
You are absolutely right, it was suggestion if you have budget . microchip has dsPic series i never used them before , dsPICDEM 28-PIN Starter Demo Board about 65 dollar.
you can use freescale 56f8300dsk demo board.
its cost 79$...
there is plenty of alternative in freescale dsp..
56f800 and 56f8300 family...
just look at the web site: www.freescale.com
to program these chips you need metrowerks codewarrior IDE. it supports free 8*16 bit c and unlimited assembly..
The dsPIC30F series of micros are well worth a look. They are 16 bit micros that can clock at up to 120MHz. Mplab is a free download and there is also a c compiler that has a 60 day free demo version you can try. The c compiler has a dsp math library and also libraries for the peripherals.
I have just started to use them and they are pretty mean mothers.