The instruction memory in the first tape out of nanosoc was implemented using SRAM. The benefit was the read bandwidth from this memory was very fast, the downside was on a power-on-reset, all the code was erased as SRAM is volatile memory. An alternative use of non-volatile memory would benefit applications where deployment of the ASIC does not allow, or simply time is not available for programming the SRAM after every power up.
Daniel Newbrook
Samuel