In my introductory classes, I introduced absolute addressing
before B-D addressing.
The instructions were specified in hexadecimal.
The program then executed at address zero using a simulator.
Pseudo instructions of one word were used for input and output.
----- Original Message -----
From: "glen herrmannsfeldt" <[email protected]>
To: <[email protected]>
Sent: Saturday, May 16, 2015 11:47 AM
Subject: absolute addressing example doesn't work
In the HLASM release 5 manual, there is an example:
"If a register is specified with base address zero, the
assembler will use it in preference to the default use
of register zero. For example:
| USING 3,0
| LA 7,5
| generates the instruction X'41703005'; in the absence of
| the USING statement, the generated instruction would
| be X'41700005'.
I suppose that works if it said "USING 0,3" but what I
really want to know how to do is to generate real absolute
addresses.
Did you try USING 0,0 ?
I now have an example from Tachyonsoft that looks like:
MYCODE START 1000
USING MYCODE,0
LOOP MP X,Y
DP X,Z
ZAP X,X(13)
B LOOP
X DC PL16'8000'
Y DC PL3'8001'
Z DC PL3'8000'
END LOOP
which seems to work. It does generate offsets from zero,
instead of from 1000 that it looks like it would.
I still don't know why it doesn't subtract 1000 from the
displacements.
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