<s>
YAP	B-Application
is	O
an	O
open-source	B-Application
,	O
high-performance	O
implementation	O
of	O
the	O
Prolog	B-Language
programming	O
language	O
developed	O
at	O
LIACC/Universidade	O
do	O
Porto	O
and	O
at	O
COPPE	O
Sistemas/UFRJ	O
.	O
</s>
<s>
Its	O
Prolog	B-Language
engine	O
is	O
based	O
in	O
the	O
WAM	O
(	O
Warren	B-Application
Abstract	I-Application
Machine	I-Application
)	O
,	O
with	O
several	O
optimizations	O
for	O
better	O
performance	O
.	O
</s>
<s>
YAP	B-Application
follows	O
the	O
Edinburgh	O
tradition	O
,	O
and	O
is	O
largely	O
compatible	O
with	O
the	O
ISO-Prolog	O
standard	O
and	O
with	O
Quintus	O
Prolog	B-Language
and	O
SICStus	B-Language
Prolog	I-Language
.	O
</s>
<s>
YAP	B-Application
has	O
been	O
developed	O
since	O
1985	O
.	O
</s>
<s>
The	O
original	O
version	O
was	O
written	O
in	O
assembly	O
,	O
C	O
and	O
Prolog	B-Language
,	O
and	O
achieved	O
high	O
performance	O
on	O
m68k-based	O
machines	O
.	O
</s>
