> On Dec 20, 2021, at 12:57:41, Alan Atkinson <[email protected]> wrote:
>
> Which is just what we did - but turned it onto a macro.
>
> MACRO
> &NAME SHI &R,&I SUBTRACT HALFWORD IMMEDIATE
> &NAME AHI &R,-(&I)
> MEXIT
> MEND
>
(Are the parentheses needed around a SETA symbol? I see a SETC symbol
might require them. I'd prefer that they appear at the point of
definition:
$C. SETC '(100-58)'
... if tradition hadn't overloaded them to mean register reference.)
There's a slight gap due to the asymmetric 2's complement range. Consider:
* if:
A EQU -X'8000'
* I can do:
SH 1,=Y(A)
* but not:
AHI 1,-A
-- gil
