Kagamin wrote:
> The Duff's device is said to be an optimization, but I get blunt device only
> 0.7% slower.
Read Duff’s post: “this loop was the bottleneck in a real-time animation
playback program”, and all the Device is doing is unwinding the loop a
few times. Optimization comes because — on
Kagamin:
> The Duff's device is said to be an optimization, but I get blunt device only
> 0.7% slower.
Compilers already know about the Duff's device, and sometimes they use it
automatically.
Bye,
bearophile
> template duffs_device(alias id1, alias id2, alias s)
> {
> void duff_loop()
> {
> if (id1 < id2)
> {
> typeof(id1) n = (id2 - id1 + 7) / 8;
> switch ((id2 - id1) % 8)
> {
> case 0:do { s();
> case 7:
On Tue, 09 Jun 2009 19:35:51 +0200, Saaa wrote:
>>> What kind of fall-throughs were these?
>>>
>>> A:
>>>
>>> case value1:
>>> case value2:
>>> case valueN:
>>> code1();
>>> break;
>>>
>>> B:
>>>
>>> case value1:
>>> code1();
>>> case value2:
>>> code2();
>>> break;
>>
>> The s
Hello Derek,
On Tue, 9 Jun 2009 16:28:58 + (UTC), BCS wrote:
I'm sorry, you don't have my sympathy on this one. There are to many
place I've used fall throught to chuck it out.
[...]
However, additionally in the default format you can use
'fallthru' to let flow drop to the next case
On Tue, 9 Jun 2009 16:28:58 + (UTC), BCS wrote:
> Hello grauzone,
>
>>> http://groups.google.com/group/net.lang.c/msg/66008138e07aa94c
>>>
>> Many people (even Brian Kernighan?) have said that the worst feature
>> of C is that switches don't break automatically before each case
>> label.
>>
Hello Ary,
Saaa wrote:
You missed the alternative syntax to get the same behaviour. But
it's a very subtle difference.
Do you mean the multiple cases?
http://www.digitalmars.com/d/1.0/statement.html#SwitchStatement
Yes, but make the "multiple cases" the *only* way to make case
statements fa
> Write a lexer and a parser.
how do you mean?
Saaa wrote:
(nah, just kidding, you're right, I didn't realize it :-P)
Ok, enough kidding around, lets get back to you helping me with 'code
generalization' :P
Write a lexer and a parser.
(nah, just kidding, you're right, I didn't realize it :-P)
Ok, enough kidding around, lets get back to you helping me with 'code
generalization' :P
> Well, yes, but you also have to prepare your mind for the change. This
> is a huge step.
;)
Saaa wrote:
Yes, but make the "multiple cases" the *only* way to make case
statements fallthrough. That would be the change.
That is the same as giving an error on case B, right?
Well, yes, but you also have to prepare your mind for the change. This
is a huge step.
(nah, just kidding, you'
I mean, the syntax stays the same.
> Yes, but make the "multiple cases" the *only* way to make case
> statements fallthrough. That would be the change.
That is the same as giving an error on case B, right?
Saaa wrote:
You missed the alternative syntax to get the same behaviour. But it's a
very subtle difference.
Do you mean the multiple cases?
http://www.digitalmars.com/d/1.0/statement.html#SwitchStatement
Yes, but make the "multiple cases" the *only* way to make case
statements fallthrough.
> You missed the alternative syntax to get the same behaviour. But it's a
> very subtle difference.
Do you mean the multiple cases?
http://www.digitalmars.com/d/1.0/statement.html#SwitchStatement
Saaa wrote:
How do you know? BCS didn't reply to my idea.
Your idea was to give an error on the case (B) he uses. Or did I miss
something?
You missed the alternative syntax to get the same behaviour. But it's a
very subtle difference.
> How do you know? BCS didn't reply to my idea.
Your idea was to give an error on the case (B) he uses. Or did I miss
something?
Saaa wrote:
What's wrong with that?
Doesn't support B :)
How about a warning instead?
The idea is that it not supporting B is something good.
I know this is your idea, but as BCS doesn't support this idea.
How do you know? BCS didn't reply to my idea.
You should have replied to him iso gr
>>> What's wrong with that?
>>
>> Doesn't support B :)
>>
>> How about a warning instead?
>
> The idea is that it not supporting B is something good.
I know this is your idea, but as BCS doesn't support this idea.
You should have replied to him iso grauzone.
I personally never had any problems wit
Saaa wrote:
What kind of fall-throughs were these?
A:
case value1:
case value2:
case valueN:
code1();
break;
B:
case value1:
code1();
case value2:
code2();
break;
The solution is to forbid fallthrough, and change the switch syntax:
switch(value) {
case 1:
case 2:
//
>> What kind of fall-throughs were these?
>>
>> A:
>>
>> case value1:
>> case value2:
>> case valueN:
>> code1();
>> break;
>>
>> B:
>>
>> case value1:
>> code1();
>> case value2:
>> code2();
>> break;
>
> The solution is to forbid fallthrough, and change the switch syntax:
>
>
grauzone wrote:
BCS wrote:
Hello grauzone,
http://groups.google.com/group/net.lang.c/msg/66008138e07aa94c
Many people (even Brian Kernighan?) have said that the worst feature
of C is that switches don't break automatically before each case
label.
Oh god, that's from 1984, and even today we'
Hello grauzone,
BCS wrote:
Hello grauzone,
http://groups.google.com/group/net.lang.c/msg/66008138e07aa94c
Many people (even Brian Kernighan?) have said that the worst feature
of C is that switches don't break automatically before each case
label.
Oh god, that's from 1984, and even today w
BCS wrote:
Hello grauzone,
http://groups.google.com/group/net.lang.c/msg/66008138e07aa94c
Many people (even Brian Kernighan?) have said that the worst feature
of C is that switches don't break automatically before each case
label.
Oh god, that's from 1984, and even today we're struggling wit
Hello grauzone,
http://groups.google.com/group/net.lang.c/msg/66008138e07aa94c
Many people (even Brian Kernighan?) have said that the worst feature
of C is that switches don't break automatically before each case
label.
Oh god, that's from 1984, and even today we're struggling with this
bulls
http://groups.google.com/group/net.lang.c/msg/66008138e07aa94c
>Many people (even Brian Kernighan?) have said that the worst feature
of C is that switches don't break automatically before each case label.
Oh god, that's from 1984, and even today we're struggling with this
bullshit in the mos
Thanks so much for all your help!I am studying hard to *loop unrolling*.
> BTW: where is this from?
It is from the spec:
http://www.digitalmars.com/d/1.0/template-mixin.html
BTW,is this Duff?
http://groups.google.com/group/net.lang.c/msg/66008138e07aa94c
BCS wrote:
> Hello Sam,
>
>> To save time ,just get to my point:I do not understand why such code
>> below inside the switch ... case statement is allowed ,what is the
>> point of do ... while...:
>
> This is a classic C thing. The short explanation is that a switch is a
> conditional, many way g
Hello Sam,
To save time ,just get to my point:I do not understand why such code
below inside the switch ... case statement is allowed ,what is the
point of do ... while...:
This is a classic C thing. The short explanation is that a switch is a conditional,
many way goto and the labels can be
To save time ,just get to my point:I do not understand why such code below
inside the switch ... case statement is allowed ,what is the point of do ...
while...:
This example uses a mixin to implement a generic Duff's device for an arbitrary
statement (in this case, the arbitrary statement is i
31 matches
Mail list logo
