Ocht ... Ben >> "FPGA logic is too vendor specific to have portable code. who needs 3 ns when 5 volt logic levels and simple packaging are more important in my mind when it comes to vintage equipment."
Not if you write in VHDL / Verilog, the instantiated lumps (eg memory) will be different but no more than the API between M$ and Borland C. And if your interest is in vintage architecture rather than vintage hardware, 5V logic has little relevance. Ben >> " Can we still get the chips?" The narrow answer is given the source VHDL/Verilog you don't need legacy silicon. Taking DG Conway's PDP/4 as an example the XC4010 is probably no more obtanium than a DS8641, and the Spartan family is only now going out of production. Ben >> " I was thinking of the western digital chip set, that had the PDP 11 or Pascal in microcode." Acording to goo's AI the Intersil 6100 and Harris HD6120 both implemented a PDP-8 on a chip; IIRC microcoded. And IIRC the DEC T-11 chip was also microcoded with an 8 bit data path. Martin -----Original Message----- From: ben via cctalk [mailto:[email protected]] Sent: 05 May 2025 01:28 To: [email protected] Cc: ben <[email protected]> Subject: [cctalk] Re: Wang TTL BASIC On 2025-05-04 3:13 p.m., Martin Bishop via cctalk wrote: > These days microcode works well in FPGAs, RAM access times of 3 ns without > pipelining, and as Xilinx BRAM comes in 1k Wd x 36b quanta eg 108 bits. BRAM > and DSP resource permits implementation of pretty much any (array of) mills. > And the architecture can provide a plurality of parallel memories and address > generators. The sort of things which were conveiveable but probably not > implementable in the bit slice days. FPGA logic is too vendor specific to have portable code. who needs 3 ns when 5 volt logic levels and simple packaging are more important in my mind when it comes to vintage equipment. http://fpgaretrocomputing.org/pdp4x/ Can we still get the chips? I was thinking of the western digital chip set, that had the PDP 11 or Pascal in microcode. A version of BASIC could have been developed, had not Microsoft cornered the basic market. > A final point is that most of the old mens techniques remain current, Wilkes > used microcode ~1950. What changes, is the price point at which you can > reduce to practice. > > Martin Here is $10.00 bribe to support RISC. Ben.
