From 96bc7be80cd119d74baba00265df4b6ff745517e Mon Sep 17 00:00:00 2001 From: Karl Williamson Date: Fri, 22 Nov 2019 15:36:50 -0700 Subject: regcomp.sym: Add comment --- regcomp.sym | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'regcomp.sym') diff --git a/regcomp.sym b/regcomp.sym index 612c3b7483..4b8670fa2c 100644 --- a/regcomp.sym +++ b/regcomp.sym @@ -34,6 +34,16 @@ # SUSPEND BRANCHJ, off 1 V 1 ; "Independent" sub-RE. # IFTHEN BRANCHJ, off 1 V 1 ; Switch, should be preceded by switcher. # GROUPP GROUPP, num 1 ; Whether the group matched. +# +# If we were to start running out of regnodes, many of the ones that are +# complements could be combined with their non-complement mates. For example, +# POSIXU could have the flags field have the bottom bit mean do we complement +# or not, and the type be shifted left 1 bit. Then all that would be needed to +# extract which to do is a mask for the complement bit, and a right shift for +# the other, an inconsequential increase in instructions. It might actually be +# clearer and slightly faster given the case statement and assignment are +# removed. Note that not everything could be collapsed: NPOSIXA, for example, +# would require special handling for performance. #* Exit points -- cgit v1.2.1