* Signed vs. unsigned compares
@ 2022-06-17 15:32 Paul Koning
2022-06-17 15:51 ` Andreas Schwab
0 siblings, 1 reply; 3+ messages in thread
From: Paul Koning @ 2022-06-17 15:32 UTC (permalink / raw)
To: GCC Development
Question for target code:
In expanding a longer-than-word compare, I need to do things differently depending on whether a signed vs. unsigned compare is needed. But it seems the compare operation applies to either. How can I do this in the target code?
paul
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Signed vs. unsigned compares
2022-06-17 15:32 Signed vs. unsigned compares Paul Koning
@ 2022-06-17 15:51 ` Andreas Schwab
2022-06-17 16:52 ` Paul Koning
0 siblings, 1 reply; 3+ messages in thread
From: Andreas Schwab @ 2022-06-17 15:51 UTC (permalink / raw)
To: Paul Koning via Gcc; +Cc: Paul Koning
On Jun 17 2022, Paul Koning via Gcc wrote:
> In expanding a longer-than-word compare, I need to do things differently depending on whether a signed vs. unsigned compare is needed. But it seems the compare operation applies to either. How can I do this in the target code?
There are both signed and unsigned comparison operations, eg. GE
vs. GEU.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Signed vs. unsigned compares
2022-06-17 15:51 ` Andreas Schwab
@ 2022-06-17 16:52 ` Paul Koning
0 siblings, 0 replies; 3+ messages in thread
From: Paul Koning @ 2022-06-17 16:52 UTC (permalink / raw)
To: Andreas Schwab; +Cc: GCC Development
> On Jun 17, 2022, at 11:51 AM, Andreas Schwab <schwab@linux-m68k.org> wrote:
>
> On Jun 17 2022, Paul Koning via Gcc wrote:
>
>> In expanding a longer-than-word compare, I need to do things differently depending on whether a signed vs. unsigned compare is needed. But it seems the compare operation applies to either. How can I do this in the target code?
>
> There are both signed and unsigned comparison operations, eg. GE
> vs. GEU.
>
> --
> Andreas Schwab, schwab@linux-m68k.org
It looks like what I need is to define additional CCmodes, to describe "cc mode valid for unsigned comparison" vs. "cc mode valid for signed comparison". Right now I don't make that distinction and that reportedly can produce bad code errors.
paul
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-06-17 15:32 Signed vs. unsigned compares Paul Koning
2022-06-17 15:51 ` Andreas Schwab
2022-06-17 16:52 ` Paul Koning
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