empire/empserver
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Store sequence numbers more compactly

Browse source 
Store them and ef_type in bit-fields.

Allocate eight bits for ef_type.  Values range from 0 to EF_GAME
(currently 16), so this is plenty.

Allocate twelve bits for sequence numbers.  Sequence number mismatches
are now missed when the numbers are equal modulo 2^12.  Still
sufficiently improbable.

Common machines store the bit-fields in a 32 bit word.  There are
twelve bits left in that word for future use.  Total savings 16 bits,
which is exactly what the previous commit spent on wider uids on
common machines.
This commit is contained in:
Markus Armbruster 2009-12-31 10:30:54 +01:00
parent ba2044be18
commit 358aee203e
15 changed files with 33 additions and 34 deletions
Download patch file Download diff file Expand all files Collapse all files

4
include/ship.h
View file

@ -63,9 +63,9 @@
struct shpstr {
/* initial part must match struct empobj */
short ef_type;
signed ef_type: 8;
unsigned shp_seqno: 12;
int shp_uid; /* unit it (ship #) */
unsigned shp_seqno;
time_t shp_timestamp; /* Last time this ship was touched. */
natid shp_own; /* owner's country num */
coord shp_x; /* x location in abs coords */