Use LGH instead of LH (or maybe even LGHI).  If you are not in AMODE 64, you 
probably don't care about messing with the high order half of the register. 
In this case, the low order bits of the register will contain the same value 
they would have contained with LH.

-----Original Message-----
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of 
Bernd Oppolzer
Sent: Saturday, October 23, 2021 3:58 PM
To: [email protected]
Subject: Re: Question about negative indexes

So this means that

LA   2,ITEM+10
LH   3,=H'-5'
LA   2,0(2,3)

will put the address ITEM+5 in register 2, at least in AMODE 24/31?

With AMODE 64, this will be a problem, because the LH instruction only
fills the right half
of the 64 bit register 3, right?

Is there a way to do this right in all AMODEs?
For positive indexes? (only, if we assume the left half to be zero?)

Thanks, kind regards

Bernd

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