Hемного о битах :)

Hello everybody.

Hаверное, это слегка офтопик, но не могу удержаться :)

Один thread c comp.arch.embedded

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От:Meindert Sprang ( snipped-for-privacy@NOcustomSPAMware.nl) Тема:Bit width?

Reading about buses, processors and memories being n bits wide makes me wonder: how wide is one bit?

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От:Grant Edwards ( snipped-for-privacy@visi.com) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me > wonder: how wide is one bit?

One bit is one bit wide.

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От:Mel Wilson ( snipped-for-privacy@the-wire.com) Тема:Re: Bit width?

> Reading about buses, processors and memories being n bits wide makes me >> wonder: how wide is one bit? > >One bit is one bit wide.

That's pretty much it. If you need expansion, you have to rely on the height. You can get some code efficiency with your semaphores if you store the P/V status in the upper half of the bit, and a tasks-waiting flag in the lower half.

Atmel ATmega processors support this really well with the BRHS and BRHC instructions: Branch If Half Carry Flag Set and ..Clear.

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От:Jim Granville ( snipped-for-privacy@designtools.co.nz) Тема:Re: Bit width?

> That's pretty much it. If you need expansion, you have >>to rely on the height. You can get some code efficiency >>with your semaphores if you store the P/V status in the >>upper half of the bit, and a tasks-waiting flag in the lower >>half. > > > Shoot, I never realized the possible height of a bit. I see some > opportunities here...

Where have you been ? - have you not seen that newest flash stores FOUR levels per programming FLASH bit ? ((Intel et al )

That means we should start talk > Atmel ATmega processors support this really well with the > BRHS and BRHC instructions: Branch If Half Carry Flag Set > and ..Clear.

But what if you need to test the OTHER half of the carry flag, clearly, they forgot the orthogonal opcodes :

BROHS : Branch If Other-Half Carry Flag Set BROHC : Branch If Other-Half Carry Flag Clear

Longer term research shows it has not stopped here :

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Imagine what THAT will do to the Processor Opcodes ?

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От:Grant Edwards ( snipped-for-privacy@visi.com) Тема:Re: Bit width?

>>That's pretty much it. If you need expansion, you have to rely >>>on the height. You can get some code efficiency with your >>>semaphores if you store the P/V status in the upper half of the >>>bit, and a tasks-waiting flag in the lower half. >> >> Shoot, I never realized the possible height of a bit. I see some >> opportunities here... > > Where have you been ? - have you not seen that newest flash > stores FOUR levels per programming FLASH bit ? ((Intel et al ) > > That means we should start talking about QUARTER BITS.

Often shortened to "quits".

Those in the USA should be comfortable with this fractional > notation, as they already use both Bit and Quarter in > currency.

The confusing thing is that a monetary bit is a half of a quarter, where a computer bit is four quarters.

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От:Ulf Samuelsson ( snipped-for-privacy@atmel.nospam.com) Тема:Re: Bit width?

>> Reading about buses, processors and memories being n bits wide makes > >> me > >> wonder: how wide is one bit? > > > >One bit is one bit wide. > > That's pretty much it. If you need expansion, you have > to rely on the height. You can get some code efficiency > with your semaphores if you store the P/V status in the > upper half of the bit, and a tasks-waiting flag in the lower > half. >

Not completely true, with ARM processors having shadow registers for the PSR, you have to wonder about the depth of a bit as well. Pushing/popping PSR registers on the stack, forces you to introduce time, the fourth dimension.

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От:Jim Stewart ( snipped-for-privacy@jkmicro.com) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me > wonder: how wide is one bit?

Troll season doesn't open for another month (:

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От:Casey ( snipped-for-privacy@cox.net) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me > wonder: how wide is one bit?

It's equal to the width of 1,000,000 microbits.

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От:Paul Keinanen ( snipped-for-privacy@sci.fi) Тема:Re: Bit width?

> Reading about buses, processors and memories being n bits wide makes me >> wonder: how wide is one bit? > >It's equal to the width of 1,000,000 microbits.

Regarding the troll season, is it 1,000,000 microbits, 1,000,000 microibits,

1000 mbits, 1024 mbits, 1,024,000 microbits or 1,048,576 microbits wide :-).

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От:Vadim Borshchev (vadim.borshchev@127.0.0.1) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me > wonder: how wide is one bit?

Imperial or metric ?

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От:Matthias Wei?er ( snipped-for-privacy@matwei.de) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me > wonder: how wide is one bit?

Maybe you are searching for

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This Bit is approximately 7cm wide and 20cm high.

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От:Greg Neff ( snipped-for-privacy@microsym.com) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me >wonder: how wide is one bit? >

Apparently, a 1 bit is 0.2280". I can't seem to find a 0 bit in my table of Numbered, Fractional, and Lettered Twist Drill Bit Sizes...

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От:Rick Merrill ( snipped-for-privacy@comTHROW.net) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me > wonder: how wide is one bit?

A Quantum bit (called a Qbit) has three states, so it is 1.5 bits "wide".

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От:Jim Stewart ( snipped-for-privacy@jkmicro.com) Тема:Re: Bit width?

> Reading about buses, processors and memories being n bits wide makes me >> wonder: how wide is one bit? > > A Quantum bit (called a Qbit) has three states, so it is 1.5 bits > "wide".

No one has yet addressed the size of virtual bits, imaginary bits and shadow bits.

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От:Jack Klein ( snipped-for-privacy@spamcop.net) Тема:Re: Bit width?

>> Reading about buses, processors and memories being n bits wide makes > >> me > >> wonder: how wide is one bit? > > > > A Quantum bit (called a Qbit) has three states, so it is 1.5 bits > > "wide". > > No one has yet addressed the size of virtual bits, imaginary > bits and shadow bits.

The width of shadow bits varies with the time of day. At dawn or sunset they are quite wide. Around noon, on the other hand, they are very, very narrow. There is a slight additional variation with latitude and season, but that is usually taken care of by a 1-bit FIR filter.

The formula for the width of imaginary bits is quite simple. It is the width of an ordinary bit multiplied by the square root of -1.

Virtual bits, however, have virtually no width at all.

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От:Ben Bradley (ben_nospam snipped-for-privacy@mindspring.com) Тема:Re: Bit width?

Reading about buses, processors and memories being n bits wide makes me >wonder: how wide is one bit?

I learned when I was a computer center janitor that a bit is narrower than a bit bucket. We had to recycle bits because the local city would levy huge fines if they found any bits in the sewage.

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Roman

Reply to
Roman Khvatov
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Как связь, _Roman_ ? ;-)

RK> how wide is one bit? RK> -+------------------------------------------------ RK> This Bit is approximately 7cm wide and 20cm high.

Я плакать!... 8-))))

До связи, Roman! /Edward/ LocalDate 04 Jun 04 - LocalTime 18:13 ...

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мыло на: nеdеliаеv(ухо)мэйл.ру

Reply to
Edward Nedeliaev

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