On 2014-11-05, at 08:54, Bernd Oppolzer wrote:
> 
> load a 31 bit address which points to storage below the bar from a fullword;
> the fullword has the first bit set (maybe because it is the last fullword in 
> an address list).
> The target of the load is a 64 bit register (say reg 5), where the left half 
> is zero.
> Now you switch to AMODE 64 and use that register for adressing ... ouch.
>  
The programmer was expected to clear bits 1-7 before using a 24-bit
address in AMODE 31.  The programmer should clear bit 32 before using
a 31-bit address in AMODE 64.

> Without excluding that address range, you risk to access wrong storage (if at
> that wrong address there is accessible storage, by chance). By excluding that
> address range, you will get an ABEND in any case, which is better.
>  
Now Java spoils that by using that address range.  ABEND is less likely.

-- gil

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