Re: 8086 register allocation

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From	gah4 <gah4@u.washington.edu>
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Subject	Re: 8086 register allocation
Date	Mon, 10 May 2021 21:19:27 -0700 (PDT)
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(Snip on x87 register allocation)

> [Normal stack machines have the top few entries in registers and do the
> spilling to memory in hardware. The x87 stack has 8 registers, which is
> a lot for a stack machine, but the spilling was broken. You can address
> into the stack but you can't really use it as a register machine. -John]

It was some years ago, but I read the story about the gcc code generator,
which is designed for register machines.  So, they don't quite treat it
as a register machine, but not a stack machine, either.

At any point in the code, there should be a known (constant) number
of items on the stack, so you can address the registers using that number.
I think that is what Intel expected, when they wrote that you can use
it as a register machine.  It would be less fun in assembly, though.

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8086 register allocation "Alexei A. Frounze" <alexfrunews@gmail.com> - 2021-05-09 14:28 -0700
  Re: 8086 register allocation Fernando <pronesto@gmail.com> - 2021-05-10 04:46 -0700
  Re: 8086 register allocation gah4 <gah4@u.washington.edu> - 2021-05-10 14:49 -0700
    Re: 8086 register allocation Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2021-05-11 03:35 +0200
      Re: 8086 register allocation gah4 <gah4@u.washington.edu> - 2021-05-10 21:19 -0700
      Re: 8086 register allocation Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2021-05-11 09:35 +0200
    Re: 8086 register allocation Thomas Koenig <tkoenig@netcologne.de> - 2021-05-11 06:44 +0000

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