<s>
The	B-Device
Amsterdam	I-Device
Compiler	I-Device
Kit	I-Device
(	O
ACK	O
)	O
is	O
a	O
retargetable	B-Application
compiler	I-Application
suite	O
and	O
toolchain	B-General_Concept
written	O
by	O
Andrew	O
Tanenbaum	O
and	O
Ceriel	O
Jacobs	O
,	O
since	O
2005	O
maintained	O
by	O
David	O
Given	O
.	O
</s>
<s>
It	O
has	O
frontends	O
for	O
the	O
following	O
programming	O
languages	O
:	O
C	B-Language
,	O
Pascal	B-Application
,	O
Modula-2	B-Language
,	O
Occam	B-Language
,	O
and	O
BASIC	O
.	O
</s>
<s>
The	O
ACK	O
was	O
known	O
as	O
MINIX	B-Operating_System
's	O
native	O
compiler	O
toolchain	B-General_Concept
until	O
the	O
MINIX	B-Operating_System
userland	B-Operating_System
was	O
largely	O
replaced	O
by	O
that	O
of	O
NetBSD	B-Device
(	O
MINIX	B-Operating_System
3.2.0	O
)	O
and	O
Clang	B-Application
was	O
adopted	O
as	O
the	O
system	O
compiler	O
.	O
</s>
<s>
It	O
was	O
originally	O
closed-source	O
software	O
(	O
that	O
allowed	O
binaries	B-Application
to	O
be	O
distributed	O
for	O
MINIX	B-Operating_System
as	O
a	O
special	O
case	O
)	O
,	O
but	O
in	O
April	O
2003	O
it	O
was	O
released	O
under	O
the	O
BSD	B-Operating_System
licenses	I-Operating_System
.	O
</s>
<s>
Maximum	O
portability	O
is	O
achieved	O
by	O
using	O
an	O
intermediate	O
language	O
using	O
bytecode	O
,	O
called	O
EM	B-Application
.	O
</s>
<s>
Each	O
language	O
front-end	O
produces	O
EM	B-Application
object	B-Application
files	I-Application
,	O
which	O
are	O
then	O
processed	O
through	O
several	O
generic	O
optimisers	O
before	O
being	O
translated	O
by	O
a	O
back-end	O
into	O
native	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
ACK	O
comes	O
with	O
a	O
generic	O
linker	O
and	O
librarian	O
capable	O
of	O
manipulating	O
files	O
in	O
the	O
ACK	O
's	O
own	O
a.out-based	O
format	O
;	O
it	O
will	O
work	O
on	O
files	O
containing	O
EM	B-Application
code	O
as	O
well	O
as	O
native	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
However	O
,	O
EM	B-Application
code	O
cannot	O
be	O
linked	O
to	O
native	O
machine	B-Language
code	I-Language
without	O
translating	O
the	O
EM	B-Application
binary	O
first	O
.	O
</s>
<s>
ACK	O
backends	O
can	O
produce	O
native	O
machine	B-Language
code	I-Language
for	O
a	O
wide	O
range	O
of	O
CPUs	O
,	O
even	O
starting	O
with	O
small	O
8	O
bit	O
CPUs	O
.	O
</s>
