For a somewhat more commercially successful take on this theme, there are a number of papers on the Symbolics 'Ivory' lisp processor that are worth a read. TI made a Lisp processor as well, but I'm less familiar with it.
Nowadays rescued at https://interlisp.org/ , with a browser emulation available.
Emacs with SBCL still isn't close to this, maybe if booting straight into Emacs, and even so.
But Xerox wasn't organized to sell even microcomputers, much less microprocessors, so it would have had to be another company that did it. Motorola, say, or Apple, but although they flirted with doing their own processor for the Lisa, they didn't do it in real life until maybe the Mac M1. (PowerPC and Newton ARM weren't really Apple designs.)
The Scheme chip is pretty different from the Dorado or from the Symbolics processors, which at the time also weren't microprocessors. But I think it's a mistake to think they had nothing to do with each other.
The only mentions I have seen were of changes for TI Explorer from Lambda, so I could not figure if it involved any kind of different circuitry
The Lambda had memory management hardware that could make use of the extra virtual address space, the CADR didn't. Any of the machines could handle 24 or 25 bit integers.
programs.
] Pointer Fields Now 25 Bits; Flag Bit Gone.
Each typed data word in Lisp machine memory used to have one bit called the "flag bit" which was not considered part of the contents of the word. This is no longer so. There is no longer a flag bit; instead, the pointer field This extra bit extends the range of integers that can be represented without allocation of storage, and also extends the precision of small-floats by one bit.
On the Lambda processor, the maximum size of virtual memory is doubled. This is the primary reason for the change. Unfortunately, the CADR mapping hardware is not able to use the extra bit as an address bit, so the maximum virtual memory size on a CADR is unchanged.
The functions %24-BIT-PLUS, %24-BIT-DIFFERENCE and %24-BIT-TIMES still produce only 24 bits of result. If you wish to have a result the full size of the pointer field, however wide that is, you should use the functions %POINTER-DIFFERENCE and %POINTER-TIMES (the last is new), and %MAKE-POINTER-OFFSET with a first argument of DTP-FIX to do addition.
The functions %FLOAT-DOUBLE, %DIVIDE-DOUBLE, %REMAINDER-DOUBLE and %MULTIPLY-FRACTIONS use the full width of the pointer field.
The values returned by SXHASH have not changed! They are always positive