>> - Commodore 64 (6510 @ ~1 MHz)
> 
> Most instructions took from 2 to 5 clock cycles, so I'd venture to say 
> that the 6510 ran between .2 and .5 MIPS.  Floating point is implemented 
> in software, and since the processor didn't have a hardware multiply 
> (and shifts were one bit at a time), it probably took dozens of machine 
> cycles for addition/subtraction and hundreds for multiplication and 
> division.  I doubt that it ever got much past ten kiloflops, and 
> probably averaged lower than that.

I recall there was no multiplication or division (in fact, I have the 
listing somewhere for a program that does repeated addition to achieve 
multiplication), but I'd forgotten about the lack of arbitrary bit 
shifts. (Not that it would matter for integer multiplication...)

Yes, definitely hundreds of instructions for floating-point arithmetic!

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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"Warp" <war### [at] tagpovrayorg> wrote

>   Just because the 16-bit operations are performed on pairs of 8-bit
> registers that doesn't make it any less of a 16-bit operation. The
> crucial thing is that you can perform a 16-bit operation with *one*
> single opcode.

It doesn't work like that. Otherwise, we should call x86 architecture 64
bits, 128 bits or even higher.

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On 13-Jul-08 20:53, Orchid XP v8 wrote:
> John VanSickle wrote:
> 
>> There were games on the Apple (6502-based) which had seven versions of 
>> any given sprite graphic so that they wouldn't have to be shifted in 
>> order to display them on the screen.  8-bit game programmers learned 
>> much about squeezing every last drop of performance out of limited 
>> speed and memory.
> 
> Wouldn't having 7 copies of the same data eat more memory?
> 
> Did it actually store 7 copies, or just precompute them?
> 
> Also... Apple made a 6502-based product??

Hmm?? Ah, good old Andy at his best.

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>> Also... Apple made a 6502-based product??
> 
> Hmm?? Ah, good old Andy at his best.

Remember: I've never actually *seen* an Apple, except on TV. So I'm not 
extremely knowledgable about them.

But anyway, I was under the impression they used to be M68k-based, and 
then PPC, and then recently went to Intel Core 2.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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On 13-Jul-08 21:47, Orchid XP v8 wrote:
>>> Also... Apple made a 6502-based product??
>>
>> Hmm?? Ah, good old Andy at his best.
> 
> Remember: I've never actually *seen* an Apple, except on TV. So I'm not 
> extremely knowledgable about them.
> 
> But anyway, I was under the impression they used to be M68k-based, and 
> then PPC, and then recently went to Intel Core 2.

Most people here might have consulted wikipedia or similar before 
posting. Then again you wouldn't be our mascot if you did. You are 
really good at mascotting you know. ;)

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andrel wrote:

> Most people here might have consulted wikipedia or similar before 
> posting. Then again you wouldn't be our mascot if you did. You are 
> really good at mascotting you know. ;)

Well if somebody says there was one, I guess there probably was one. I 
was more interjecting with surprise than actually denying the fact. ;-)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Warp wrote:
>   With the z80 you can have 16-bit literals, perform 16-bit ALU operations
> (such as additions, substractions, shifts, etc), you can address the entire
> memory with one single 16-bit register, etc. I don't understand what's *not*
> 16-bit about the z80.

OK. I must be confusing the Z80 with the 8080, perhaps. I know the 8080 
had no 16-bit registers except PC and SP.  HL was two registers, for 
example.

>   Just because the 16-bit operations are performed on pairs of 8-bit
> registers that doesn't make it any less of a 16-bit operation.

OK. I guess we're just disagreeing about whether that ability makes a 
CPU an "8-bit CPU" or a "16-bit CPU".

I mean, I've used mainframes with "string" type opcodes that would 
operate on 1KBytes at a time. That wouldn't really make them a KByte 
CPU. :-)

>> Almost everyone calls the processor the number of bits on the data bus, 
>> fwiw, when talking about this stuff.
> 
>   How is that even useful?

Very useful for hardware type people. Also unambiguous. Plus, I didn't 
claim it was useful. I merely said it's what I noticed when I read all 
the literature.

Maybe because the "definitive" literature written by places like Intel 
are generally addressing people who build motherboards for their chips 
and such.

>   I understand "8-bit" to mean "has 8-bit registers, and you can only
> perform an 8-bit operation with a single opcode, because registers can
> only hold 8 bits of data". Likewise for any other bitsize.

Well, the 6502 had 16-bit absolute jumps, IIRC. I wouldn't call it a 
16-bit CPU.

>   Btw, didn't the 386 usually have a 16-bit data bus? The 386 is still
> a 32-bit processor, though.

I don't remember the bus size. But at this point, I think we're more 
arguing what you call the CPU than anything real about the CPU.

-- 
Darren New / San Diego, CA, USA (PST)
  Helpful housekeeping hints:
   Check your feather pillows for holes
    before putting them in the washing machine.

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somebody <x### [at] ycom> wrote:
> "Warp" <war### [at] tagpovrayorg> wrote

> >   Just because the 16-bit operations are performed on pairs of 8-bit
> > registers that doesn't make it any less of a 16-bit operation. The
> > crucial thing is that you can perform a 16-bit operation with *one*
> > single opcode.

> It doesn't work like that. Otherwise, we should call x86 architecture 64
> bits, 128 bits or even higher.

  I was talking about *all* the ALU operations, such as addition,
substraction, etc. In some processors there might be a few special
opcodes that perform an operation with larger numbers by using several
registers (such as the shifting of two registers as if they were one
in x86), but these are rare.

  If it was about data bus width, then some 32-bit processors would
in reality be 128-bit or 256-bit because they have really wide data
buses. Heck, if I remember correctly, even the Pentium4 has a 64-bit
data bus, yet it's still a 32-bit processor.

-- 
                                                          - Warp

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andrel <a_l### [at] hotmailcom> wrote:
> Most people here might have consulted wikipedia or similar before 
> posting.

  When I write like this, I get accused of bullying.

-- 
                                                          - Warp

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On 13-Jul-08 22:17, Orchid XP v8 wrote:
> andrel wrote:
> 
>> Most people here might have consulted wikipedia or similar before 
>> posting. Then again you wouldn't be our mascot if you did. You are 
>> really good at mascotting you know. ;)
> 
> Well if somebody says there was one, I guess there probably was one. I 
> was more interjecting with surprise than actually denying the fact. ;-)
> 
FYI we are talking about the Apple II without which the whole concept of 
a personal computer that anyone could buy would not have existed. OK 
another computer would have done it a few years later, but that is not 
the point.

It feels a bit like someone working with genetic material everyday and 
then say: 'Mendel, never heard of that guy, or was it a girl?'. Anyway, 
if we compiled a list of entertaining books about the history of 
computers and surrounding science is there any change you'd read them? 
When is your birthday?

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