Luke Kenneth Casson Leighton wrote:
so yes, you're right: the CPU *itself* doesn't know - it starts up and executes from a fixed address, but depending on the CPU, the [unchangeable] on-board micro-bootloader does "know".
Also I think there's an OpenCores VHDL FAT reader, so if a design has an FPGA for "glue" that could preload RAM while the CPU's in reset state. Then there's the Raspberry Pi which apparently uses the GPU to do the job.
-- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues]