AW: Re: An explanation for branch performance?

[Peter Hunkeler]

>>
>>           L     R4,=A(1*1000*1000*1000)
>>           LTR   R4,R4
>>           J     LOOP
>> *
>> LOOP     DS   0D                  .LOOP START
>>           B     NEXT
>>
>> NEXT     JCT   R4,LOOP
>
> The loop starts with a branch ... I tested it twice - when the CC is matched
> (branch happens) and when it is not matched (falls through)
>
> 1. When the CC is matched and branching happens, CPU TIME=2.94 seconds
> 2. When the CC is not matched the code falls through, CPU TIME=1.69
> seconds - a reduction of 42%

> Uhm... I don't see any conditional branch at the start of the loop that 
> branches or falls through?


I'm with Fred here.  Out of curiosity, the code you posted seems to be 
incomplete. Is it?


--


Peter Hunkeler



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