NOTES   [plain text]


$NetBSD: NOTES,v 1.3 1997/10/20 03:41:15 lukem Exp $

Berkeley Yacc reflects its origins.  The reason so many routines
use exactly six register variables is that Berkeley Yacc was
developed on a VAX using PCC.  PCC placed at most six variables
in registers.  I went to considerable effort to find which six
variables most belonged in registers.  Changes in machines and
compilers make that effort worthless, perhaps even harmful.

[Given the previous paragraph, and the fact that GCC does not respect
 register declarations, and the fact that much of the rest of the
 4.4lite2 release had "register" declarations extirpated, I've removed
 most of the register declarations from the code. I left them in the
 generated skeleton code "for the hell of it" but they probably should
 go from there, too. -- pm, July 1997]

[I totally removed the register stuff; we've deprecated it elsewhere
 in the tree now -- lukem, October 1997]

The code contains many instances where address calculations are
performed in particular ways to optimize the code for the VAX.