* Why compile.c ?
@ 1994-04-19 16:22 yodaiken
0 siblings, 0 replies; 2+ messages in thread
From: yodaiken @ 1994-04-19 16:22 UTC (permalink / raw)
What is the rationale for compile.c in the sparc version of Plan9?
Why not simply write out the assembly code?
^ permalink raw reply [flat|nested] 2+ messages in thread
* Why compile.c ?
@ 1994-04-19 17:17 rob
0 siblings, 0 replies; 2+ messages in thread
From: rob @ 1994-04-19 17:17 UTC (permalink / raw)
Why? Why do by hand what a machine can do just
as well or better?
The SPARC MMU is inexcusably badly designed.
To make a single kernel that supports all variants
one must either write oodles of ugly assembly code,
with loops that must be unrolled for speed, or generate
code at boot-time tailored to the machine at hand.
We chose the latter approach because it's really
less code to maintain. I wrote the compiler in just
a couple of hours one afternoon. It's very easy stuff.
Since some of the code must be generated - for
example, cache line sizes vary from model to model -
what the hell? Why not generate it all? Easy, and
susceptible to adaptation as SUN's creative minds
continue to design hardware.
^ permalink raw reply [flat|nested] 2+ messages in thread
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