Yeah, I just answered another post on this. It explains my error
-- I was reading fast and thinking 1 byte immediates, not the
multi-byte of the newer instructions.
Still stuck in pre-z/Arch instructions. But, I am slowly using
the newer ones.
Regards,
Steve Thompson
On 02/23/2017 09:28 AM, Charles Mills wrote:
Replication would then expand outside of the instruction and into the
instruction stream
Not necessarily. AHI R1,2X'FF', were it valid, would presumably generate
exactly the same machine code as the valid AHI R1,X'FFFF'. One could, for
example, write a series of macros (with names for example like AHI@) that would
accept immediate operands with replication factors exactly as the OP wished,
and assemble them into valid machine code.
Charles
-----Original Message-----
From: IBM Mainframe Assembler List [mailto:[email protected]] On
Behalf Of Steve Thompson
Sent: Thursday, February 23, 2017 4:56 AM
To: [email protected]
Subject: Re: HLASM anomaly
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 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
On 02/22/2017 04:18 PM, Melvyn Maltz wrote:
Immediate operands won't accept a duplication factor...why not ?
Can't find a reason in the HLASM manual
Try these...
CFI R1,4X'FF'
CFI R1,X'FFFFFFFF'
CFI R1,-1
AHI R1,2X'FF'
AHI R1,X'FFFF'
AHI R1,-1
Melvyn Maltz
