On 2017-02-23, at 11:16, Paul Gilmartin wrote:
>
> What are the limits on the operand of AHI? What of:
>
> A EQU -32768
> DC Y(A)
> AHI R1,A OK, I believe.
>
> B EQU 32767
> DC Y(B)
> AHI R1,B OK, I believe.
>
> c EQU 65535
> DC Y(C)
> AHI R1,C OK ???
>
> Is the operand of AHI treated modulo 2^16, or ?
>
So, I RTFM and learned little:
• HLASM
• HLASM Language Reference
• Machine instruction statements
• Operand entries
• Immediate data
HLASM Language Reference
SC26-4940-06
...
Immediate data must be specified as absolute expressions whose range
of values depends on the machine instruction for which the data is
required. The immediate data is assembled into its binary representation.
"depends on the machine instruction". So I need to read the PoOps,
which says, for AHI:
... The second operand is two bytes in length and is treated
as a 16-bit signed binary integer. ...
Does "treated as" mean it's treated modulo size of field? Or ...?
That seems to be a HLASM question, not a zSeries question, so I guess
HLASM deserves an RCF; it shouldn't pass the responsibility (to PoOps?),
which offers no clarification. Are the limits of a halfword operand:
(-32768,32767)
(0,65535)
(-32768,65535)
Other (specify)?
Lore is not documentation.
-- gil
