The one place where I have found that I cannot replace a branch with a branch
relative is in a construct based on a return code:
CALL SOMEFUNC
B *+4(15)
J RC0
J RC4
J RC8
J RC12
and so on. The closest I can come, in baseless code, is:
CALL SOMEFUNC
LARL R10,JUMPTABLE
ALR R10,R15
L R10,0(,R10)
BR R10
JUMPTABLE DS 0F
DC A(RC0,RC4,RC8,RC12)
And if I understand it correctly, this will perform poorly due to Address
Generation Interlock.
--
John McKown
Systems Engineer IV
IT
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> -----Original Message-----
> From: IBM Mainframe Assembler List
> [mailto:[email protected]] On Behalf Of Potts, Michael
> Sent: Friday, October 29, 2010 8:55 AM
> To: [email protected]
> Subject: Re: Modernizing code
>
> Another quick win is to replace branches with jumps (B to J, BE to JE,
> and so on). It will take more work to replace them in macros
> and figure
> out ways to handle branches into branch tables. It seems like you're
> well on your way to removing base registers for addressing code!
>
> -----Original Message-----
>
> >Do you have any other ideas ? I do not want to rewrite too
> much, so I'm
> >looking for "quick wins" like the two above.
>
>
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