16 Sep
2002
16 Sep
'02
7:10 p.m.
On Sep 16, 22:15, Jerome H. Fine wrote:
I understand your answer. Under normal situations
(when MACRO-11
source is translated and the actual code is placed into an OBJ file which
is then LINKed), both ways are acceptable. BUT, Patrick was setting up
the program via ODT (see line four). If Patrick did not realize what the
'
character in the string 177566' meant, perhaps he
just put 177566 instead
so that the three word instruction became:
001000 Mov #110,XBUF 012767 000110 177566
which, of course, is NOT what Patrick intended. However
001000 MovB #110,@#XBUF 112737 000110 177566
is correct and does the job.
So it is not that the first method is incorrect, but for some it might be
confusing.
Hmm. I'd argue that it *is* incorrect, or at the very least, bad practice.
Relative addresses are meant for situations where the target is a label,
indicating something which must move if the code does, like the target of a
JSR, or a block of data attached to the code; if you mean to indicate
something like a memory-mapped register, which has an absolute and
invariant address, you should use absolute addressing.
Given that Pat said he was going to enter the code using ODT, I imagine he
expected the MACRO output to be the correct numbers to enter. But he used
the wrong addressing mode to do that :-)
My personal opinion is that the MACRO-11 program
should make the
situation plain, but unfortunately I suspect that MACRO-11 will never
be modified by the present owners.
I suspect you're right :-) Besides, the output is meant for the linker,
not ODT, and I'm not sure how you could make it really plain that the
numerical value in the output is not what the linker will turn it into,
without a lot of (usually) unneccessary clutter.
--
Pete Peter Turnbull
Network Manager
University of York
16 Sep
16 Sep
11:25 p.m.
Pete and Jerome,
On Tue, Sep 17, 2002 at 07:13:10AM +0000, Pete Turnbull wrote:
You may want to know that Patrick is not using real MACRO-11, but a cross-
assembler under Linux. So it may be wrong but at least it can be changed
easily.
Pete, I replied to your other post in this thread. I'm just trying to
understand what "the right thing to do" is here.
-- Derek
On Sep 16, 22:15, Jerome H. Fine wrote:
My personal
opinion is that the MACRO-11 program should make the
situation plain, but unfortunately I suspect that MACRO-11 will never
be modified by the present owners.
I suspect you're right :-) Besides, the output is meant for the linker,
not ODT, and I'm not sure how you could make it really plain that the
numerical value in the output is not what the linker will turn it into,
without a lot of (usually) unneccessary clutter. 
17 Sep
17 Sep
1:54 a.m.
Pete Turnbull wrote:
On Sep 16,
22:15, Jerome H. Fine wrote:
I understand your answer. Under normal situations (when MACRO-11
source is translated and the actual code is placed into an OBJ file which
is then LINKed), both ways are acceptable. BUT, Patrick was setting up
the program via ODT (see line four). If Patrick did not realize what the '
character in the string 177566' meant,
perhaps he just put 177566 instead
so that the three word instruction became:
001000 Mov #110,XBUF 012767 000110 177566
which, of course, is NOT what Patrick intended. However
001000 MovB #110,@#XBUF 112737 000110 177566
is correct and does the job.
So it is not that the first method is incorrect, but for some it might be
confusing.
Hmm. I'd argue that it *is* incorrect, or at the very least, bad
practice. Relative addresses are meant for situations where the
target is a label,
indicating something which must move if the code does, like the target of a
JSR, or a block of data attached to the code; if you mean to indicate
something like a memory-mapped register, which has an absolute and
invariant address, you should use absolute addressing.
PLUS, if the instruction is JSR,R0 LOCATION, then PIC (Position
Independent Code) results as well. I also agree that absolute addressing
is BEST (@#XBUF) when a memory-mapped register which has an
invariant absolute address is being referenced.
Given that Pat said he was going to enter the code
using ODT, I imagine he
expected the MACRO output to be the correct numbers to enter. But he used
the wrong addressing mode to do that :-)
Only insofar as the listed output was concerned. So again, bad practice.
My personal
opinion is that the MACRO-11 program should make the
situation plain, but unfortunately I suspect that MACRO-11 will never
be modified by the present owners.
I suspect you're right :-) Besides, the
output is meant for the linker,
not ODT, and I'm not sure how you could make it really plain that the
numerical value in the output is not what the linker will turn it into,
without a lot of (usually) unneccessary clutter.
8132
days inactive
8132
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2 comments
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participants (3)
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dpeschel＠eskimo.com -
jhfinepw4z＠compsys.to -
pete＠dunnington.u-net.com