Language-specific CPUs

Jim Battle wrote: Dang, I have the book. I bought used recently it because of its i432 section, but didn't recognize it was the same book I had read so many years ago. Chapter 8 of "Advances in Computer Architecture" describes the SYMBOL computer, designed and built buy Fairchild Camera, and operated at Iowa State. Only one was built. The design was started in the mid 60s. Here is an excerpt: The language is described as "a high-level language architecture. Its instruction set is a one-for-one reverse Polish representation of the system's programming language, the SYMBOL programming language (SPL), and the compilation process is performed by the machine rather than the software." "An initially startling aspect of SYMBOL is the first goal; the phrase 'directly ... implemented in hardware' means that SYMBOL contains virtually no software (it does contain some software, but the software performs only a few auxiliary functions, and the system can be operated with no software), and it contains no microcode; all the system's functions are implemented as sequential logic networks. For instance, the 'compiler' is a hardware sequential logic network, the memory-allocation and page-replacement algorithms are sequential logic networks, the functions that interpret end-user terminal commands are sequential logic networks, and so on." The machine was built as a collection of specialized processors. One did parsing, one did numeric formatting, etc. When the user ran a program, it was handed off between the specialized task processors, and the user was unaware of what was going on under the hood. The compilation was so fast that programs were all stored in source code form. The machine could process 75,000 lines per minute. They had a design that could handle 300K lines/minute, but it was never built. When a single user was on the system and submitted a trivial program, the time from hitting carriage return after typing "RUN" until the program was done was 315 microseconds. Other factoids: 64b core memory, 4 uS cycle time. SPL had two data types: scalars and lists. Numeric scalars could be up to 99 mantissa digits, with one or two exponent digits. Decimal math. Lists were limited in length only by the amount of of memory available.