On 3/4/20, Mark Filipak <markfilipak.windows+ffm...@gmail.com> wrote: > I thought further and decided to redo my FPGA presentation with better > analogies. I hope you enjoy it. > > Starting with the basics: Logic gates come in 2 flavors: AND and OR; and > it's from them, alone, that all other digital elements are made. > > FSMs (finite state machines) are complex combinations of logic gates > that execute (i.e., change state) sequentially. A particular FSM's > sequence is determined by 2 things: 1, external input conditions, and 2, > the FSM's current state. > > CPU core units (code cracker, execution unit, cache controller, etc.) > are special-purpose FSMs. You can visualize an FSM as a player piano and > a CPU core as a group of player pianos. > > Microcodes: Microcodes are 'piano roll' sequences that 'play' CPU core > unit 'pianos'. > > Machine codes: Machine codes cause the microcode 'piano rolls' to be > switched en masse: As each particular machine code arrives at the CPU, > all the microcode 'piano rolls' are switched to the rolls that, given > the current state of the CPU's execution unit, are appropriate for > 'playing' that particular machine code's 'tune'. It's that switching > that makes CPU core units different from ordinary FSMs. > > The only CPU core unit 'piano' that doesn't change its 'tune' is the > code cracker. The code cracker's microcode 'piano roll' never changes > because the code cracker is the 'piano' that switches the 'piano rolls' > of the other 'pianos', and how it accomplishes that never changes. What > does change is the identification of the new, replacement 'piano roll' > that's swapped in. That identification is embedded in the machine code. > > Thusly, CPUs differ from fixed sequential machines: CPUs self-modify. > Note that the self-modifying is not permanent but persists solely for > the current machine code cycle, then changes for the next machine code. > The code cracker can do this because of fields embedded in machine codes > and the execution unit's current state. > > Machine codes: All programs must be converted to machine codes prior to > arriving at the CPU. They can be converted in advance (e.g., "compiled", > such as written in 'C') or converted on the fly (e.g., "interpreted", > such as written in Python). > > Thusly, programs are layers removed from machine code and machine code > is layers removed from microcode. > > Returning to the basics, FPGAs are collections of uncommitted logic > gates that can be configured to make anything that can be made with > logic gates. In addition to a sea of gates, some FPGAs contain hand > crafted (compact) peripherals (e.g., SPI, HDMI) and even CPUs (e.g., ARM). > > SoS (software-on-silicon) vendors, such as NGCodec, design the > particular configurations that turn FPGAs into dedicated chips that > perform specific tasks such as processing video streams. The designs can > be in the form of, 1, 'hard-wired' FSMs (difficult design, longer > development, later to the market, but wicked fast), or 2, additions to > an on-chip CPU (easier design, shorter development, sooner to the > market, but slower). > > Of course, processing video streams can be done in a computer's CPU. > That's what ffmpeg does.
Not 100% correct. _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
