PSEUDO
BC
OP
FUNCTION
EQUIVALENT
B
Branch Unconditional
BC XIF', Sl
NOP
No Operation
Be X'O', Sl
BH
Branch on High
BC X'2',Sl
BL
Branch on Low
BC X'4', Sl
BE
Branch on Equal
BC X'8',Sl
BO
Branch on Overflow
(Arithmetic) or Branch
if Ones (after TM)
BC Xlll,Sl
BP
Branch on Plus
BC X'2', Sl
BM
Branch on -Minus
(Arithmetic) or Branch
if Mixed (after TM)
BC X'4',Sl
BZ
Branch on Zero
(Arithmetic) or Branch
if Zero (After TM)
BC X'8',Sl
Examples:
OPERATION
OPERAND
B
BEGIN
BH
ERR
BZ
ZERO
Exercise:
1.
What does the symbol
*
(asterisk), in column 1
of the Assembler Coding form, tell the Assem-
bler program?
2.
What is a redundant name?
3.
If a statement has a symbol in the name field
and an
*
(asterisk) as its first operand, which
of the following Is true?
a.
b.
c.
Name address and asterisk address are
the same.
Asterisk address is name address plus
one.
Asterisk address is name address plus
two.
4.
Indicate the type of the following self-defining
value.
Self-Defining Value
C'9'
X'4645'
CIA'
246
C'A9'
22
5.
Indicate whether the follOWing statements are
true
0
r false.
T
F
T
F
T
F
T
F
T
F
a.
b.
c.
d.
e.
A DS code reserves a portion of
memory and clears the reserved
area to blanks.
Three types of constants may be de-
fined with the DC instruction.
The length of a constant must be ex-
plicit.
If the length of a constant defined by
a single DC statement is
17
bytes
the rightmost byte will be truncated.
A hexadecimal constant consisting of
an odd number of hexadecimal digits
will have a zero digit padded at the
left end and the statement will be
flagged in the listing.
6.
Describe the use of the EXTRN and ENTRY
codes.
7.
How many external symbols may be identified
by an EXTRN statement?
8.
Explain the restrictions imposed by the Assem-
bler on the placing of ENTRY statements in the
program.
9.
Using the Assembler coding form, write the
Assembler and machine instructions necessary
to:
a.
b.
c.
d.
Set the Location Counter to an initial set-
ting of 1000.
Provide linkage to a subroutine called
ABLE which is not a part of this program.
Set aside a working storage area of 75
bytes.
Provide an address constant of 3000.
10. Define the following abbreviations as used by the
machine instructions.
a.
L
b.
c.
d.
S
e.