Ah, I see why you all are having a problem with this.
And me, being an old ALC programmer, this is intuitively obvious.
In fact, there are several changes to HLASM that I disagreed
with, because they then caused programs I had written earlier to
start getting informative messages, where they didn't get them
before.
And when I first scanned the instructions, I was going quite
fast, and didn't catch the need for more than 1 byte of immediate
data.
So, you want the immediate area to be filled with a replication.
But that means that the assembler now must pay attention to the
replication value -- which it may not know until after the
instruction has to be generated, and ensure that it does not
exceed the immediate are of the instruction.
And the more such logic that is added to HLASM, the slower it
gets (my problem with this stuff).
I wish that IBM had made PLX or PL/AS a product for you
High-level Language programmers to work with...
Regards,
Steve Thompson
On 02/23/2017 08:41 AM, Robin Vowels wrote:
From: "Steve Thompson" <ste...@copper.net>
Sent: Thursday, February 23, 2017 11:55 PM
What does "immediate" mean to you?
In this case, it means immediately available within the
instruction itself.
Replication would then expand outside of the instruction
Why? It is an Immediate instruction.
and into the instruction stream. That would then cause the next
byte, beyond the instruction, to be an OPCODE by instruction
fetch (IF) using the PSW's Instruction counter (IC).
When an instruction is fetched, the IC is advanced by the
length of the instruction -- which is based on the OP code (it
defines the length of the instruction).
Accordingly, there is nothing in the instruction to tell IF
that this instruction has a different length for updating the IC.
It would help to read the Principles of Operations manual for
more than just the instructions that you want to use.
Understanding how the machine actually works can keep you out
of trouble and make use of nuances at the same time.
Regards,
Steve Thompson
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