Hello.

I have a question that I have been curious about for some time.

Let's say I have to represent an integer that can only have values between 1 and 10.

In general, which would be the fastest?

8-bit byte
16-bit short
32-bit integer

Cheers!

Keith Fuller

keithfx@hawtmail.com (<--you know what I mean)

On later intel processors, 32 bits.

"Keith Fuller" <Keith_member@pathlink.com> wrote in message news:b9689u$n73$1@digitaldaemon.com...
> Hello.
>
> I have a question that I have been curious about for some time.
>
> Let's say I have to represent an integer that can only have values between
1 and
> 10.
>
> In general, which would be the fastest?
>
> 8-bit byte
> 16-bit short
> 32-bit integer
>
> Cheers!
>
> Keith Fuller
>
> keithfx@hawtmail.com (<--you know what I mean)
>
>
>

    The general rule is that the natural word machines are the faster.
    16 bit for 286 or lower, 32 bit for 386+.

"Walter" <walter@digitalmars.com> escribió en el mensaje news:b96hk1$10dq$1@digitaldaemon.com...
> On later intel processors, 32 bits.
>
> "Keith Fuller" <Keith_member@pathlink.com> wrote in message news:b9689u$n73$1@digitaldaemon.com...
> > Hello.
> >
> > I have a question that I have been curious about for some time.
> >
> > Let's say I have to represent an integer that can only have values
between
> 1 and
> > 10.
> >
> > In general, which would be the fastest?
> >
> > 8-bit byte
> > 16-bit short
> > 32-bit integer
> >
> > Cheers!
> >
> > Keith Fuller
> >
> > keithfx@hawtmail.com (<--you know what I mean)
> >
> >
> >
>
>

hello

Javier Gutiérrez a écrit:
>     The general rule is that the natural word machines are the faster.
>     16 bit for 286 or lower, 32 bit for 386+.
>

hum .. it seems to me that it depend on the model too. manipulating 32 bit datas with 16 bit registers is quite slow !
at least 16 bit datas should be aligned on 32 bit boundary
using 32 bit registers on 16 bit model ? it works (use assembly)
i don't know if it is faster but i know it adds a 8 bit opcode.

roland



> "Walter" <walter@digitalmars.com> escribió en el mensaje
> news:b96hk1$10dq$1@digitaldaemon.com...
>
>>On later intel processors, 32 bits.
>>
>>"Keith Fuller" <Keith_member@pathlink.com> wrote in message
>>news:b9689u$n73$1@digitaldaemon.com...
>>
>>>Hello.
>>>
>>>I have a question that I have been curious about for some time.
>>>
>>>Let's say I have to represent an integer that can only have values
>>
> between
>
>>1 and
>>
>>>10.
>>>
>>>In general, which would be the fastest?
>>>
>>>8-bit byte
>>>16-bit short
>>>32-bit integer
>>>
>>>Cheers!
>>>
>>>Keith Fuller
>>>
>>>keithfx@hawtmail.com (<--you know what I mean)
>>>
>>>
>>>
>>
>>
>
>

"Walter" <walter@digitalmars.com> wrote in message news:b96hk1$10dq$1@digitaldaemon.com...
> On later intel processors, 32 bits.

My understanding is that 386 and newer processors are well optimized for simple algebra with 8/16/32-bit registers.  Any add/sub operation will only take 1 clock (or close to it) regardless if it's using AL, AX, or EAX. However, I'm not sure how it reacts with div/mul.

I would be interested in seeing someone profile these types of operations.

I think it is more a matter of memory access. Inside the CPU, yes, it probably doesn't matter.

keithfx@h*tmail.com

In article <bd0kr0$mq2$1@digitaldaemon.com>, Shawn Poulson says...
>
>My understanding is that 386 and newer processors are well optimized for simple algebra with 8/16/32-bit registers.  Any add/sub operation will only take 1 clock (or close to it) regardless if it's using AL, AX, or EAX. However, I'm not sure how it reacts with div/mul.
>
>I would be interested in seeing someone profile these types of operations.
>

    Yes, it is a memory issue.
    You can get the complete info at
http://www.penguin.cz/~literakl/intel/intel.html

"Keith Fuller" <Keith_member@pathlink.com> escribió en el mensaje news:bd9pv0$1klh$1@digitaldaemon.com...
> I think it is more a matter of memory access.
> Inside the CPU, yes, it probably doesn't matter.
>
> keithfx@h*tmail.com
>
> In article <bd0kr0$mq2$1@digitaldaemon.com>, Shawn Poulson says...
> >
> >My understanding is that 386 and newer processors are well optimized for simple algebra with 8/16/32-bit registers.  Any add/sub operation will
only
> >take 1 clock (or close to it) regardless if it's using AL, AX, or EAX. However, I'm not sure how it reacts with div/mul.
> >
> >I would be interested in seeing someone profile these types of
operations.
> >
>
>