Re: [Tinycc-devel] Speed?

[Thomas Harning Jr.]

At 03:08 AM 11/21/2003, you wrote:

> But c is declared as "int", not as "unsigned int". This will not give
> the same result if c is neg.
Yeah it will, it should output a right arithmetic shift on signed ints and 
doing that preserves sign by extending the highest order bit.  Did quite a 
bit of assembly and floating point/integer math by direct gate-based 
hardware design, c, SPARC assembly, so I'm quite sure on that.
Heh, with studying the SPARC and comparing to intel... sure has LOTS more 
registers to use and a very nice variable passing scheme as opposed to 
stack based.  Cant wait til the nex gen Intel comes out to be a good 
consumer CPU..... though that'd mean that this project could probably use 
an overhaul, since generating I386 code would be suboptimal.

For >>= and signed integers, a right arithmetic shift should come 
out.  [highest order bit extended into "empty" spots]
For >>= and unsigned ints, a right logical shift should come 
out.               [zeroes extended into "empty" spots]
For <<= and any.. a left logical shift should come out [there is no such 
left arithmetic shift].        [zeroes extended into "empty" spots]