• Eric (8/8) Jul 31 2014 Suppose I have some memory allocated on the heap, and I have
• bearophile (5/11) Jul 31 2014 Use something like this (but make sure the length is correct):
• Eric (6/18) Jul 31 2014 Thanks. That really works. I timed doing
• bearophile (4/9) Jul 31 2014 Take a look at the asm!
• Vlad Levenfeld (2/5) Jul 31 2014 I use DMD and Dub, how do I view the asm?
• Eric (11/18) Jul 31 2014 Actually I did't think to look at the asm, mainly because
• anonymous (7/9) Jul 31 2014 -d

"Eric" <eric makechip.com> writes:

Suppose I have some memory allocated on the heap, and I have
two pointers pointing to the beginning and end of a contiguous 
segment
of that memory.  Is there a way I can convert those two pointers
to an array slice without actually copying anything within the 
segment?

Thx,
Eric

"bearophile" <bearophileHUGS lycos.com> writes:

Eric:

 Suppose I have some memory allocated on the heap, and I have
 two pointers pointing to the beginning and end of a contiguous 
 segment
 of that memory.  Is there a way I can convert those two pointers
 to an array slice without actually copying anything within the 
 segment?

Use something like this (but make sure the length is correct):

auto mySlice = ptr1[0 .. ptr2 - ptr1];

Bye,
bearophile

"Eric" <eric makechip.com> writes:

On Thursday, 31 July 2014 at 19:43:00 UTC, bearophile wrote:
 Eric:

 Suppose I have some memory allocated on the heap, and I have
 two pointers pointing to the beginning and end of a contiguous 
 segment
 of that memory.  Is there a way I can convert those two 
 pointers
 to an array slice without actually copying anything within the 
 segment?

 Use something like this (but make sure the length is correct):

 auto mySlice = ptr1[0 .. ptr2 - ptr1];

 Bye,
 bearophile

Thanks. That really works.  I timed doing

auto mySlice = ptr1[0 .. ptr2 - ptr1]; 1,000,000 times

versus

auto mySlice = ptr1[0 .. ptr2 - ptr1].dup; 1,000,000 times

and I am quite convinced the data is not being copied.

"bearophile" <bearophileHUGS lycos.com> writes:

Eric:

 Thanks. That really works.  I timed doing

 auto mySlice = ptr1[0 .. ptr2 - ptr1]; 1,000,000 times

 versus

 auto mySlice = ptr1[0 .. ptr2 - ptr1].dup; 1,000,000 times

 and I am quite convinced the data is not being copied.

Take a look at the asm!

Bye,
bearophile

"Vlad Levenfeld" <vlevenfeld gmail.com> writes:

On Thursday, 31 July 2014 at 20:43:11 UTC, bearophile wrote:
 Take a look at the asm!

 Bye,
 bearophile

I use DMD and Dub, how do I view the asm?

"Eric" <eric makechip.com> writes:

On Thursday, 31 July 2014 at 20:59:46 UTC, Vlad Levenfeld wrote:
 On Thursday, 31 July 2014 at 20:43:11 UTC, bearophile wrote:
 Take a look at the asm!

 Bye,
 bearophile

 I use DMD and Dub, how do I view the asm?

Actually I did't think to look at the asm, mainly because
I've never bothered to do it before.  But I was just reading 
Adam's
book the other day, and I remember seeing this:

objdump -d  -M intel simpleOctal

Not sure what the switches are for; the name of the program is 
simpleOctal.
But the name of the utility is objdump. (on Linux).  Not sure 
about Windoze.

-Eric

"anonymous" <anonymous example.com> writes:

On Thursday, 31 July 2014 at 21:50:25 UTC, Eric wrote:
 objdump -d  -M intel simpleOctal

 Not sure what the switches are for;

-d
disassemble - Essential if you want to, well, disassemble.

-M intel
Intel syntax - Because no one likes AT&T syntax. Wikipedia has a
comparison:
http://en.wikipedia.org/wiki/X86_assembly_language#Syntax