<s>
Basic	B-Device
Assembly	I-Device
Language	I-Device
(	O
BAL	O
)	O
is	O
the	O
commonly	O
used	O
term	O
for	O
a	O
low-level	O
programming	O
language	O
used	O
on	O
IBM	B-Application
System/360	I-Application
and	O
successor	O
mainframes	O
.	O
</s>
<s>
Originally	O
,	O
"	O
Basic	B-Device
Assembly	I-Device
Language	I-Device
"	O
applied	O
only	O
to	O
an	O
extremely	O
restricted	O
dialect	O
designed	O
to	O
run	O
under	O
control	O
of	O
IBM	B-Application
Basic	I-Application
Programming	I-Application
Support	I-Application
(	O
BPS/360	B-Application
)	O
on	O
systems	O
with	O
only	O
8KB	O
of	O
main	O
memory	O
,	O
and	O
only	O
a	O
card	B-Device
reader	I-Device
,	O
a	O
card	B-Device
punch	I-Device
,	O
and	O
a	O
printer	O
for	O
input/output	B-General_Concept
—	O
thus	O
the	O
word	O
"	O
Basic	O
"	O
.	O
</s>
<s>
However	O
,	O
the	O
full	O
name	O
and	O
the	O
initialism	O
"	O
BAL	O
"	O
almost	O
immediately	O
attached	O
themselves	O
in	O
popular	O
use	O
to	O
all	O
assembly-language	O
dialects	O
on	O
the	O
System/360	B-Application
and	O
its	O
descendants	O
.	O
</s>
<s>
BAL	O
for	O
BPS/360	B-Application
was	O
introduced	O
with	O
the	O
System/360	B-Application
in	O
1964	O
.	O
</s>
<s>
Assemblers	B-Language
on	O
other	O
System/360	B-Application
operating	B-General_Concept
systems	I-General_Concept
through	O
System/370	B-Device
,	O
System/390	B-Device
,	O
and	O
System	B-Device
z	I-Device
,	O
as	O
well	O
as	O
the	O
UNIVAC	B-Device
Series	I-Device
90	I-Device
mainframes	O
made	O
by	O
Sperry	O
Corporation	O
,	O
and	O
the	O
BS2000	B-Application
Mainframes	O
currently	O
made	O
by	O
Fujitsu	O
,	O
inherited	O
and	O
extended	O
its	O
syntax	O
.	O
</s>
<s>
The	O
latest	O
derived	O
language	O
is	O
known	O
as	O
the	O
IBM	B-Device
High-Level	I-Device
Assembler	I-Device
(	O
HLASM	B-Device
)	O
.	O
</s>
<s>
Programmers	O
utilizing	O
this	O
family	O
of	O
assemblers	B-Language
also	O
refer	O
to	O
them	O
as	O
ALC	O
,	O
(	O
for	O
Assembly	B-Language
Language	I-Language
Coding	O
)	O
,	O
or	O
simply	O
"	O
assembler	B-Language
"	O
.	O
</s>
<s>
The	O
architecture	O
of	O
IBM	O
mainframes	O
has	O
undergone	O
several	O
extensions	O
over	O
the	O
years	O
,	O
including	O
System/360	B-Application
,	O
System/370	B-Device
,	O
System/370	B-Device
XA	O
,	O
ESA/370	O
,	O
ESA/390	B-Device
,	O
and	O
z/Architecture	B-Device
.	O
</s>
<s>
Each	O
of	O
these	O
architectures	O
has	O
retained	O
compatibility	B-Device
with	O
most	O
of	O
the	O
features	O
of	O
its	O
predecessor	O
.	O
</s>
<s>
BAL	O
uses	O
the	O
native	O
instruction	B-General_Concept
set	I-General_Concept
of	O
these	O
machines	O
.	O
</s>
<s>
It	O
is	O
thus	O
closer	O
to	O
the	O
hardware	O
than	O
third-generation	O
languages	O
such	O
as	O
COBOL	B-Application
.	O
</s>
<s>
The	O
instruction	B-General_Concept
set	I-General_Concept
consists	O
of	O
the	O
low-level	O
operations	O
supported	O
by	O
the	O
architecture	O
,	O
such	O
as	O
:	O
</s>
<s>
The	O
extreme	O
simplicity	O
of	O
these	O
operations	O
means	O
that	O
the	O
source	O
code	O
of	O
a	O
program	O
written	O
in	O
assembler	B-Language
will	O
usually	O
be	O
much	O
longer	O
than	O
an	O
equivalent	O
program	O
in	O
,	O
say	O
,	O
COBOL	B-Application
or	O
Fortran	B-Application
.	O
</s>
<s>
In	O
the	O
past	O
,	O
the	O
speed	O
of	O
hand-coded	O
assembler	B-Language
programs	I-Language
was	O
often	O
felt	O
to	O
make	O
up	O
for	O
this	O
drawback	O
,	O
but	O
with	O
the	O
advent	O
of	O
optimizing	O
compilers	O
,	O
C	B-Language
for	O
the	O
mainframe	O
,	O
and	O
other	O
advances	O
,	O
assembler	B-Language
has	O
lost	O
much	O
of	O
its	O
appeal	O
.	O
</s>
<s>
IBM	O
continues	O
to	O
upgrade	O
the	O
assembler	B-Language
,	O
however	O
,	O
and	O
it	O
is	O
still	O
used	O
when	O
the	O
need	O
for	O
speed	O
or	O
very	O
fine	O
control	O
is	O
paramount	O
.	O
</s>
<s>
Another	O
reason	O
to	O
use	O
assembler	B-Language
is	O
that	O
not	O
all	O
operating	B-General_Concept
system	I-General_Concept
functions	O
can	O
be	O
accessed	O
in	O
high	O
level	O
languages	O
.	O
</s>
<s>
The	O
application	O
program	O
interface	O
of	O
mainframe	O
operating	B-General_Concept
systems	I-General_Concept
is	O
defined	O
as	O
a	O
set	O
of	O
assembly	B-Language
language	I-Language
"	O
macro	O
"	O
instructions	O
,	O
that	O
typically	O
invoke	O
Supervisor	B-Operating_System
Call	I-Operating_System
(	O
SVC	B-Operating_System
)	O
[	O
e.g.	O
,	O
on	O
z/OS	O
]	O
or	O
Diagnose	O
(	O
DIAG	O
)	O
[	O
on	O
,	O
e.g.	O
,	O
z/VM	O
]	O
instructions	O
to	O
invoke	O
operating	B-General_Concept
system	I-General_Concept
routines	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
use	O
operating	B-General_Concept
system	I-General_Concept
services	O
from	O
programs	O
written	O
in	O
high-level	O
languages	O
by	O
use	O
of	O
assembler	B-Language
subroutines	O
.	O
</s>
<s>
The	O
format	O
of	O
assembler	B-Language
language	I-Language
statements	O
reflects	O
the	O
layout	O
of	O
an	O
80-column	O
punched	O
card	O
,	O
though	O
successive	O
versions	O
have	O
relaxed	O
most	O
of	O
the	O
restrictions	O
.	O
</s>
<s>
The	O
operation	O
code	O
would	O
be	O
only	O
a	O
machine	B-Language
instruction	I-Language
(	O
macros	O
were	O
not	O
available	O
)	O
,	O
making	O
it	O
usually	O
1	O
,	O
2	O
,	O
3	O
,	O
or	O
rarely	O
4	O
letters	O
.	O
</s>
<s>
Basic	B-Device
Assembly	I-Device
Language	I-Device
does	O
not	O
allow	O
statement	O
continuation	O
.	O
</s>
<s>
Later	O
versions	O
of	O
the	O
assembler	B-Language
indicate	O
continuation	O
by	O
the	O
appearance	O
of	O
any	O
non-blank	O
character	O
in	O
column	O
72	O
of	O
the	O
statement	O
being	O
continued	O
.	O
</s>
<s>
Basic	B-Device
Assembly	I-Device
Language	I-Device
requires	O
that	O
column	O
72	O
be	O
blank	O
.	O
</s>
<s>
Basic	B-Device
Assembly	I-Device
language	I-Device
also	O
permits	O
an	O
alternate	O
statement	O
format	O
with	O
the	O
statement	O
starting	O
in	O
column	O
25	O
,	O
allowing	O
the	O
assembled	O
instruction	O
to	O
be	O
punched	O
into	O
the	O
same	O
card	O
beginning	O
in	O
column	O
1	O
.	O
</s>
<s>
This	O
option	O
was	O
not	O
continued	O
in	O
later	O
versions	O
of	O
the	O
assembler	B-Language
.	O
</s>
<s>
Three	O
main	O
types	O
of	O
instructions	O
are	O
found	O
in	O
the	O
source	O
code	O
of	O
a	O
program	O
written	O
in	O
assembler	B-Language
.	O
</s>
<s>
Assembler	B-Language
instructions	O
,	O
sometimes	O
termed	O
directives	O
,	O
pseudo	O
operations	O
or	O
pseudoops	O
on	O
other	O
systems	O
,	O
are	O
requests	O
to	O
the	O
assembler	B-Language
to	O
perform	O
various	O
operations	O
during	O
the	O
code	O
generation	O
process	O
.	O
</s>
<s>
One	O
of	O
the	O
more	O
important	O
assembler	B-Language
instructions	O
is	O
USING	O
,	O
which	O
supports	O
the	O
truncated	O
addressing	O
of	O
the	O
S/360	B-Application
architecture	O
.	O
</s>
<s>
It	O
guides	O
the	O
assembler	B-Language
in	O
determining	O
what	O
base	O
register	O
and	O
offset	O
it	O
should	O
use	O
for	O
a	O
relative	O
address	O
.	O
</s>
<s>
There	O
is	O
a	O
one-to-one	O
relationship	O
with	O
machine	B-Language
instructions	I-Language
.	O
</s>
<s>
The	O
full	O
mnemonic	O
instruction	B-General_Concept
set	I-General_Concept
is	O
described	O
in	O
the	O
Principles	O
of	O
Operation	O
manual	O
for	O
each	O
processor	O
.	O
</s>
<s>
Unlike	O
assemblers	B-Language
for	O
some	O
other	O
systems	O
,	O
such	O
as	O
X86	B-Language
assembly	I-Language
language	I-Language
,	O
register	O
mnemonics	O
are	O
not	O
reserved	O
symbols	O
but	O
are	O
defined	O
through	O
EQU	O
statements	O
elsewhere	O
in	O
the	O
program	O
.	O
</s>
<s>
This	O
improves	O
readability	O
of	O
assembler	B-Language
language	I-Language
programs	O
and	O
provides	O
a	O
cross-reference	O
of	O
register	O
usage	O
.	O
</s>
<s>
Thus	O
typically	O
you	O
may	O
see	O
the	O
following	O
in	O
an	O
assembler	B-Language
program	I-Language
:	O
</s>
<s>
Some	O
notable	O
instruction	O
mnemonics	O
are	O
BALR	O
for	O
a	O
call	O
storing	O
the	O
return	O
address	O
and	O
condition	O
code	O
in	O
a	O
register	O
,	O
SVC	B-Operating_System
,	O
DIAG	O
,	O
and	O
ZAP	O
.	O
</s>
<s>
System/360	B-Application
machine	B-Language
instructions	I-Language
are	O
one	O
,	O
two	O
,	O
or	O
three	O
halfwords	O
in	O
length	O
(	O
two	O
to	O
6	O
bytes	O
)	O
.	O
</s>
<s>
Originally	O
there	O
were	O
four	O
instruction	O
formats	O
,	O
designated	O
by	O
the	O
first	O
two	O
bits	O
of	O
the	O
operation	O
code	O
field	O
;	O
z/Architecture	B-Device
added	O
additional	O
formats	O
.	O
</s>
<s>
Basic	O
assembler	B-Language
language	I-Language
does	O
not	O
support	O
macros	O
.	O
</s>
<s>
Later	O
assembler	B-Language
versions	O
allow	O
the	O
programmer	O
to	O
group	O
instructions	O
together	O
into	O
macros	O
and	O
add	O
them	O
to	O
a	O
library	O
,	O
which	O
can	O
then	O
be	O
invoked	O
in	O
other	O
programs	O
,	O
usually	O
with	O
parameters	O
,	O
like	O
the	O
preprocessor	O
facilities	O
in	O
C	B-Language
and	O
related	O
languages	O
.	O
</s>
<s>
Macros	O
can	O
include	O
conditional	O
assembler	B-Language
instructions	O
,	O
such	O
as	O
AIF	O
(	O
an	O
‘	O
if’	O
construct	O
)	O
,	O
used	O
to	O
generate	O
different	O
code	O
according	O
to	O
the	O
chosen	O
parameters	O
.	O
</s>
<s>
That	O
makes	O
the	O
macro	O
facility	O
of	O
this	O
assembler	B-Language
very	O
powerful	O
.	O
</s>
<s>
While	O
multiline	O
macros	O
in	O
C	B-Language
are	O
an	O
exception	O
,	O
macro	O
definitions	O
in	O
assembler	B-Language
can	O
easily	O
be	O
hundreds	O
of	O
lines	O
.	O
</s>
<s>
Most	O
programs	O
will	O
require	O
services	O
from	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
and	O
the	O
OS	O
provides	O
standard	O
macros	O
for	O
requesting	O
those	O
services	O
.	O
</s>
<s>
These	O
are	O
analogous	O
to	O
Unix	B-Application
system	I-Application
calls	O
.	O
</s>
<s>
For	O
instance	O
,	O
in	O
MVS	B-Application
(	O
later	O
z/OS	O
)	O
,	O
STORAGE	O
(	O
with	O
the	O
OBTAIN	O
parameter	O
)	O
dynamically	O
allocates	O
a	O
block	O
of	O
memory	O
,	O
and	O
GET	O
retrieves	O
the	O
next	O
logical	O
record	O
from	O
a	O
file	O
.	O
</s>
<s>
Unlike	O
Unix	B-Application
system	I-Application
calls	O
,	O
macros	O
are	O
not	O
standardized	O
across	O
operating	B-General_Concept
systems	I-General_Concept
though	O
.	O
</s>
<s>
The	O
following	O
fragment	O
shows	O
how	O
the	O
logic	O
"	O
If	O
SEX	O
=	O
'	O
M	O
 '	O
,	O
add	O
1	O
to	O
MALES	O
;	O
else	O
,	O
add	O
1	O
to	O
FEMALES	O
"	O
would	O
be	O
performed	O
in	O
assembler	B-Language
.	O
</s>
<s>
The	O
following	O
is	O
the	O
ubiquitous	O
Hello	O
world	O
program	O
,	O
and	O
would	O
,	O
executing	O
under	O
an	O
IBM	O
operating	B-General_Concept
system	I-General_Concept
such	O
as	O
OS/VS1	B-Application
or	O
MVS	B-Application
,	O
display	O
the	O
words	O
'	O
Hello	O
World	O
 '	O
on	O
the	O
operator	O
's	O
console	O
:	O
</s>
<s>
WTO	O
is	O
an	O
assembler	B-Language
macro	O
that	O
generates	O
an	O
operating	B-General_Concept
system	I-General_Concept
call	O
.	O
</s>
<s>
Because	O
of	O
saving	O
registers	O
and	O
later	O
restoring	O
and	O
returning	O
,	O
this	O
small	O
program	O
is	O
usable	O
as	O
a	O
batch	O
program	O
invoked	O
directly	O
by	O
the	O
operating	B-General_Concept
system	I-General_Concept
Job	B-Application
control	I-Application
language	I-Application
(	O
JCL	O
)	O
like	O
this	O
:	O
</s>
<s>
With	O
the	O
exception	O
of	O
the	O
assemblers	B-Language
for	O
the	O
IBM	B-Device
System/360	I-Device
Model	I-Device
20	I-Device
,	O
the	O
IBM	O
assemblers	B-Language
were	O
largely	O
upward-compatible	O
.	O
</s>
<s>
OS/360	B-Application
assemblers	B-Language
were	O
originally	O
designated	O
according	O
to	O
their	O
memory	O
requirements	O
.	O
</s>
<s>
This	O
cross-assembler	O
runs	O
on	O
a	O
7090	B-Device
or	I-Device
7094	I-Device
system	O
and	O
was	O
used	O
while	O
System/360	B-Application
was	O
in	O
development	O
.	O
</s>
<s>
The	O
assembler	B-Language
for	O
BPS	B-Application
is	O
the	O
true	O
"	O
basic	O
assembler.	O
"	O
</s>
<s>
It	O
was	O
intended	O
to	O
be	O
loaded	O
from	O
cards	O
and	O
would	O
run	O
on	O
an	O
8KB	O
System/360	B-Application
(	O
except	O
Model	O
20	O
)	O
.	O
</s>
<s>
The	O
Basic	B-Application
Operating	I-Application
System	I-Application
has	O
two	O
assembler	B-Language
versions	O
.	O
</s>
<s>
Assembler	B-Language
D	O
was	O
the	O
DOS/360	B-Application
assembler	B-Language
for	O
machines	O
with	O
a	O
memory	O
size	O
of	O
16KB	O
.	O
</s>
<s>
An	O
F-level	O
assembler	B-Language
was	O
also	O
available	O
for	O
DOS	O
machines	O
with	O
64KB	O
or	O
more	O
.	O
</s>
<s>
D	O
assemblers	B-Language
offered	O
nearly	O
all	O
the	O
features	O
of	O
higher	O
versions	O
.	O
</s>
<s>
Assembler	B-Language
E	O
was	O
designed	O
to	O
run	O
on	O
an	O
OS/360	B-Application
system	O
with	O
a	O
minimum	O
of	O
32KB	O
of	O
main	O
storage	O
,	O
with	O
the	O
assembler	B-Language
itself	O
requiring	O
15KB	O
.	O
</s>
<s>
Assembler	B-Language
F	O
can	O
run	O
under	O
either	O
DOS/360	B-Application
or	O
OS/360	B-Application
on	O
a	O
system	O
with	O
a	O
64KB	O
memory	O
,	O
with	O
the	O
assembler	B-Language
requiring	O
44KB	O
.	O
</s>
<s>
These	O
assemblers	B-Language
are	O
a	O
standard	O
part	O
of	O
OS/360	B-Application
;	O
the	O
version	O
that	O
was	O
generated	O
was	O
specified	O
at	O
system	B-Application
generation	I-Application
(	O
SYSGEN	O
)	O
.	O
</s>
<s>
"	O
With	O
certain	O
exceptions	O
,	O
the	O
IBM	B-Device
System/360	I-Device
Model	I-Device
44	I-Device
Programming	O
System	O
Assembler	B-Language
Language	I-Language
is	O
a	O
selected	O
subset	O
of	O
the	O
languages	O
available	O
in	O
the	O
IBM	B-Application
System/360	I-Application
programming	O
support.	O
"	O
</s>
<s>
Most	O
significantly	O
the	O
Model	O
44	O
assembler	B-Language
lacked	O
support	O
for	O
macros	O
and	O
continuation	O
statements	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
it	O
had	O
a	O
number	O
of	O
features	O
not	O
found	O
in	O
other	O
System/360	B-Application
assemblers	B-Language
—	O
notably	O
instructions	O
to	O
update	O
a	O
card	B-Device
image	I-Device
source	O
dataset	O
,	O
named	O
common	O
,	O
and	O
implicit	O
definition	O
of	O
SETA	O
assembler	B-Language
variables	O
.	O
</s>
<s>
"	O
Assembler	B-Language
G	O
"	O
is	O
a	O
set	O
of	O
modifications	O
made	O
to	O
Assembler	B-Language
F	O
in	O
the	O
1970s	O
by	O
the	O
University	O
of	O
Waterloo	O
(	O
Assembler	B-Language
F	O
was/is	O
open	O
source	O
)	O
.	O
</s>
<s>
Enhancements	O
are	O
mostly	O
in	O
better	O
handling	O
of	O
input/output	B-General_Concept
and	O
improved	O
buffering	O
which	O
speed	O
up	O
assemblies	O
considerably	O
.	O
</s>
<s>
"	O
Assembler	B-Language
G	O
"	O
was	O
never	O
an	O
IBM	O
product	O
.	O
</s>
<s>
Assembler	B-Language
H	O
Version	O
2	O
was	O
announced	O
in	O
1981	O
and	O
includes	O
support	O
for	O
Extended	O
Architecture	O
(	O
XA	O
)	O
,	O
including	O
the	O
AMODE	O
and	O
RMODE	O
directives	O
.	O
</s>
<s>
It	O
was	O
replaced	O
by	O
High	O
Level	O
Assembler	B-Language
.	O
</s>
<s>
Assembler	B-Language
XF	O
is	O
an	O
upgrade	O
of	O
Assembler	B-Language
F	O
which	O
includes	O
the	O
new	O
System/370	B-Device
architecture	O
instructions	O
.	O
</s>
<s>
This	O
version	O
provides	O
a	O
common	O
assembler	B-Language
for	O
OS/VS	O
and	O
DOS/VS	O
systems	O
.	O
</s>
<s>
Assembler	B-Language
XF	O
requires	O
a	O
minimum	O
partition/region	O
size	O
of	O
64KB	O
(	O
virtual	O
)	O
.	O
</s>
<s>
High	O
Level	O
Assembler	B-Language
(	O
HLASM	B-Device
)	O
,	O
announced	O
in	O
1992	O
as	O
a	O
licensed	O
program	O
"	O
becomes	O
the	O
default	O
translator	O
for	O
System/370	B-Device
(	O
TM	O
)	O
and	O
System/390	B-Device
(	O
TM	O
)	O
operating	O
environments.	O
"	O
</s>
<s>
The	O
assembler	B-Language
supports	O
the	O
MVS	B-Application
,	O
VSE	O
,	O
and	O
VM	O
operating	B-General_Concept
systems	I-General_Concept
and	O
successors	O
.	O
</s>
<s>
As	O
of	O
Release	O
6	O
it	O
now	O
is	O
able	O
to	O
run	O
under	O
Linux	B-Application
on	I-Application
IBM	I-Application
Z	I-Application
and	O
generate	O
ELF	O
or	O
GOFF	B-Application
object	O
files	O
.	O
</s>
<s>
It	O
features	O
a	O
long	O
list	O
of	O
mostly	O
usability	O
enhancements	O
,	O
and	O
incorporates	O
the	O
SLAC	O
(	O
Stanford	O
Linear	O
Accelerator	O
)	O
modifications	O
to	O
Assembler	B-Language
H	O
.	O
Among	O
features	O
added	O
were	O
an	O
indication	O
of	O
CSECT/DSECT	O
for	O
location	O
counter	O
,	O
dependent	O
and	O
labelled	O
USING	O
statements	O
,	O
a	O
list	O
of	O
USING	O
statements	O
currently	O
active	O
,	O
an	O
indication	O
of	O
whether	O
a	O
variable	O
is	O
read	O
or	O
written	O
in	O
the	O
cross-reference	O
,	O
and	O
allowing	O
mixed-case	O
symbol	O
names	O
.	O
</s>
<s>
The	O
RSECT	O
directive	O
(	O
Read-only	O
Control	O
Section	O
)	O
allows	O
the	O
assembler	B-Language
to	O
check	O
reentrancy	O
on	O
a	O
per-section	O
basis	O
.	O
</s>
<s>
RSECT	O
was	O
previously	O
"	O
undocumented	O
and	O
inconsistently	O
implemented	O
in	O
Assembler	B-Language
H.	O
"	O
HLASM	B-Device
is	O
the	O
current	O
assembler	B-Language
for	O
IBM	O
mainframe	O
systems	O
as	O
of	O
2012	O
.	O
</s>
<s>
The	O
IBM	B-Device
System/360	I-Device
Model	I-Device
44	I-Device
Programming	O
System	O
Assembler	B-Language
processes	O
a	O
language	O
that	O
is	O
a	O
"	O
selected	O
subset	O
"	O
of	O
OS/360	B-Application
and	O
DOS/360	B-Application
assembler	B-Language
language	I-Language
.	O
</s>
<s>
The	O
assembler	B-Language
for	O
the	O
System/360	B-Application
Model	I-Application
67	I-Application
Time	I-Application
Sharing	I-Application
System	I-Application
has	O
a	O
number	O
of	O
differences	O
in	O
directives	O
to	O
support	O
unique	O
TSS	B-Application
features	O
.	O
</s>
<s>
There	O
have	O
been	O
several	O
IBM-compatible	O
assemblers	B-Language
for	O
special	O
environments	O
.	O
</s>
<s>
The	O
Univac	B-Device
90/60	I-Device
,	I-Device
90/70	I-Device
and	I-Device
90/80	I-Device
series	O
from	O
Unisys	O
was	O
designed	O
to	O
accept	O
IBM-format	O
assembler	B-Language
,	O
as	O
the	O
machine	O
series	O
was	O
a	O
workalike	O
to	O
the	O
S/360	B-Application
and	O
S/370	B-Device
.	O
</s>
<s>
The	O
Fujitsu	O
BS2000	B-Application
series	O
was	O
also	O
built	O
as	O
a	O
370	O
workalike	O
from	O
the	O
same	O
resource	O
as	O
Univac	O
,	O
and	O
is	O
still	O
in	O
use	O
in	O
some	O
parts	O
of	O
Europe	O
.	O
</s>
<s>
Dignus	O
LLC	O
Systems/ASM	O
is	O
an	O
HLASM-compatible	O
assembler	B-Language
that	O
can	O
run	O
natively	O
on	O
IBM	O
systems	O
or	O
as	O
a	O
cross-assembler	O
.	O
</s>
<s>
z390	O
is	O
an	O
assembler	B-Language
and	O
System	B-Device
390	I-Device
emulator	O
also	O
written	O
by	O
Don	O
Higgins	O
and	O
is	O
programmed	O
in	O
Java	B-Language
.	O
</s>
<s>
Penn	O
State	O
University	O
authored	O
a	O
package	O
called	O
ASSIST	B-Application
,	O
which	O
includes	O
a	O
System	B-Device
370	I-Device
assembler	B-Language
and	O
interpreter	O
.	O
</s>
<s>
Tachyon	O
Software	O
LLC	O
markets	O
the	O
Tachyon	O
Assembler	B-Language
Workbench	O
which	O
runs	O
on	O
Windows	O
,	O
Linux/x86	O
,	O
Linux	O
for	O
S/390	B-Device
and	O
zSeries	O
,	O
AIX	O
and	O
Solaris	O
.	O
</s>
<s>
GNU	B-Application
Assembler	I-Application
(	O
gas	O
)	O
is	O
part	O
of	O
the	O
GNU	B-Application
Compiler	I-Application
Collection	I-Application
(	O
gcc	B-Application
)	O
for	O
Linux	B-Application
on	I-Application
OS/390	I-Application
and	I-Application
IBM	I-Application
Z	I-Application
.	O
</s>
<s>
This	O
assembler	B-Language
has	O
a	O
unique	O
syntax	O
that	O
is	O
incompatible	O
with	O
other	O
assemblers	B-Language
for	O
IBM	O
architectures	O
.	O
</s>
