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Groups > comp.lang.c > #161741
| From | Keith Thompson <Keith.S.Thompson+u@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: naked switches |
| Date | 2021-07-08 01:00 -0700 |
| Organization | None to speak of |
| Message-ID | <8735sp8cbm.fsf@nosuchdomain.example.com> (permalink) |
| References | <06a0049a-2d7d-40f0-899a-fb35c9a15d5fn@googlegroups.com> |
Robert Finch <robfi680@gmail.com> writes:
> I have been working on a C/C++ like compiler. One feature supported in
> the compiler is naked switches. A naked switch omits the range
> checking code that is normally associated with the switch
> statement. Omitting this code can improve performance at the risk of a
> crash if invalid cases are processed. I am wondering if there is a
> similar option in other C compilers? Or would this just be an
> automatic optimization at high levels?
What range checking code are you referring to? Can you give an example
in C that demonstrates the change in behavior? How does a default:
label affect it?
> Normal Switch:
>
> ; switch(x) {
> ldo $t0,64[$fp]
> sge $t1,$t0,#1 ; x varies between 1 and 12
> sle $t2,$t0,#12
> and $t1,$t1,$t2
> beq $t1,TestSwitch_89
> sub $t0,$t0,#1
> sll $t0,$t0,#4
> ldo $t0,TestSwitch_116[$t0]
> jmp $t0
>
> Naked Switch
> ; switch(x; naked) {
> ldo $t0,64[$fp]
> sub $t0,$t0,#1
> sll $t0,$t0,#4
> ldo $t0,TestSwitch_144[$t0]
> jmp $t0
>
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips
void Void(void) { Void(); } /* The recursive call of the void */
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naked switches Robert Finch <robfi680@gmail.com> - 2021-07-07 16:39 -0700
Re: naked switches Bart <bc@freeuk.com> - 2021-07-08 01:26 +0100
Re: naked switches Kaz Kylheku <563-365-8930@kylheku.com> - 2021-07-08 01:57 +0000
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-08 09:16 +0200
Re: naked switches Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-07-08 01:00 -0700
Re: naked switches Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-07-08 03:25 -0700
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-07-08 06:58 -0700
Re: naked switches Bart <bc@freeuk.com> - 2021-07-08 15:52 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-08 17:52 +0200
Re: naked switches Bart <bc@freeuk.com> - 2021-07-08 17:51 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 10:01 +0200
Re: naked switches Bart <bc@freeuk.com> - 2021-07-09 11:09 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 13:14 +0200
Re: naked switches Manfred <noname@add.invalid> - 2021-07-09 15:35 +0200
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 16:51 +0200
Re: naked switches Manfred <noname@add.invalid> - 2021-07-09 18:23 +0200
Re: naked switches Bart <bc@freeuk.com> - 2021-07-09 16:07 +0100
Re: naked switches Manfred <noname@add.invalid> - 2021-07-09 18:41 +0200
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-10 11:02 +0200
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 19:20 +0200
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-07-09 10:46 -0700
Re: naked switches Kaz Kylheku <563-365-8930@kylheku.com> - 2021-07-09 19:56 +0000
Re: naked switches Bart <bc@freeuk.com> - 2021-07-09 22:01 +0100
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-07-09 15:07 -0700
Re: naked switches Bart <bc@freeuk.com> - 2021-07-09 23:30 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-10 12:17 +0200
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-07-08 10:18 -0700
Re: naked switches Bart <bc@freeuk.com> - 2021-07-08 18:43 +0100
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-07-08 15:32 -0700
Re: naked switches Kaz Kylheku <563-365-8930@kylheku.com> - 2021-07-08 17:47 +0000
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-07-08 15:45 -0700
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 10:27 +0200
Re: naked switches Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-09 11:13 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 13:30 +0200
Re: naked switches Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-11 00:39 -0700
Re: naked switches scott@slp53.sl.home (Scott Lurndal) - 2021-07-11 14:06 +0000
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-07-11 08:01 -0700
Re: naked switches Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-16 03:53 -0700
Re: naked switches scott@slp53.sl.home (Scott Lurndal) - 2021-07-16 14:47 +0000
Re: naked switches Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-09-30 06:09 -0700
Re: naked switches Robert Finch <robfi680@gmail.com> - 2021-09-30 07:03 -0700
Re: naked switches Bart <bc@freeuk.com> - 2021-07-09 13:44 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-10 13:28 +0200
Re: naked switches Bart <bc@freeuk.com> - 2021-07-10 13:04 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-10 15:39 +0200
Re: naked switches Bart <bc@freeuk.com> - 2021-07-10 15:08 +0100
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-10 17:34 +0200
Re: naked switches Bart <bc@freeuk.com> - 2021-07-10 17:47 +0100
Re: naked switches Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-11 00:57 -0700
Re: naked switches Tim Rentsch <tr.17687@z991.linuxsc.com> - 2021-07-16 03:51 -0700
Re: naked switches Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-07-08 11:40 -0700
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 10:38 +0200
Re: naked switches Kaz Kylheku <563-365-8930@kylheku.com> - 2021-07-08 17:33 +0000
Re: naked switches scott@slp53.sl.home (Scott Lurndal) - 2021-07-08 17:47 +0000
Re: naked switches Kaz Kylheku <563-365-8930@kylheku.com> - 2021-07-08 17:58 +0000
Re: naked switches scott@slp53.sl.home (Scott Lurndal) - 2021-07-08 19:13 +0000
Re: naked switches Kaz Kylheku <563-365-8930@kylheku.com> - 2021-07-09 02:30 +0000
Re: naked switches David Brown <david.brown@hesbynett.no> - 2021-07-09 10:41 +0200
Re: naked switches Bonita Montero <Bonita.Montero@gmail.com> - 2021-09-30 18:04 +0200
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