Extended instruction set (multiply instructions and instructions for handling larger program memories)
The R4700 improved on the repeat rate of floating point multiply instructions.
If executing multiply instructions, a 3 X multiplicand is generated.
An extended arithmetic element option added actual multiply and divide instructions.
The third unit executes multiply and divide instructions.
The pipelines are not identical, one executes the majority of instructions and the other only multiply instructions.
For example the multiply and divide instructions were done in software and needed to be specifically built into the operating system to be used.
Most modern compilers would not actually generate two multiply instructions and a store for this statement.
It added multiple-cycle multiply and divide instructions in a somewhat independent on-chip unit.
This is used as an extension to the accumulator for multiply and divide instructions.