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by philiplu 1131 days ago
Own C compiler? IIRC, that's not quite true. I worked on the C/C++ compiler team at Microsoft from 1991 to 2007, and I don't remember us producing a drop of the compiler just for Excel. I do think there was a special compiler flag for them, though, that fixed the order in which global variables were laid out to duplicate the source order. It was either Excel or Word that saved state by taking the addresses of the first and last global variables of interest, then dumping all memory in that range to disk. The flag was something like -bzalign. The bz stood for Bozo, which hints at the compiler team's thoughts on the practice.
1 comments
tedunangst 1131 days ago
They may be referring to a telephone version of the story that excel was originally compiled to p-code for compactness.
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philiplu 1131 days ago
That sounds reasonable. I'd forgotten about the p-code version. I think that was dead by the time I started. I was also fortunate enough to avoid working on the 16-bit compiler backend, and just worked on the 32-bit, referred to internally as the n386 backend, which was pretty much a complete rewrite. The p-code backend would have been a variant of the 16-bit version.
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tragomaskhalos 1129 days ago
The 'own C compiler' is from Joel Spolsky from when he worked at Microsoft: https://www.joelonsoftware.com/2001/10/14/in-defense-of-not-.... And indeed this states that it was p-code. I'm old enough to remember when p-code was - briefly - a very hot idea.
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philiplu 1128 days ago
I know we shipped p-code for general usage, not just internal like Excel. But it might have been internal-only in the mid to late 80s. I found a link [1] talking about some p-code internals, from April 1992, by the guy who hired me at Microsoft about a year before that. The compiler team definitely viewed Excel as one of their most important customers, and were willing to do lots of work to satisfy them.

So p-code wasn't actually dead when I started, but instead shipped with the C/C++ 7.0 compiler, which predated Visual C++. I never worked on C7, since that was 16-bit, and p-code wasn't part of any 32-bit compiler, as I recall.

[1] https://techshelps.github.io/MSDN/BACKGRND/html/msdn_c7pcode...

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