I've looked at some subroutines for the 8052. It should make writing programs a little bit easier. But even so I expect speed to suffer, with having multplication of a 32 bit or 16 bit number involve going threw hundreds of instructions.

What exactly is a sighned number? One of the bits represents a positive or negative number?

Why does taking two's complement of some numbers give the magnitude? Would $FE have a magnitude of 1? Would the MSB for $FE represent -.

Thanks, Martin