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ru.linux
- RU.LINUX ---------------------------------------------------------------------
From : Valentin Nechayev 2:5020/400 01 Dec 2002 00:39:27
To : "Alexandr S. Agranovsky"
Subject : Re: embedded linux
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>>> Alexandr S. Agranovsky wrote:
ASA> Вернемся к нашим баранам.
ASA> Hасчет NS 16000 я не знаю, но 68000 и 80186 были
ASA> 16-разрядными. 186-й мог адресовать столько же памяти, сколько
ASA> и 8086 (т.е. 1 мбайт, это 20-разрядная адресная шина)
Мне с 68000 встречаться не приходилось, но вот результат простейших
раскопок на гугле:
==={{{
The 68000 was a clever compromise. When the 68000 was introduced,
16-bit busses were really the most practical size. However, the 68000
was designed with 32-bit registers and address spaces, on the
assumption that hardware prices would fall. To address the perceived
markets, the actual 68000 was designed in three forms. The base-form
had a 24-bit address, and a 16-bit data bus. The short form, the
68008, had an 18-bit address (possibly 19 or 20 bits, at least one
firm addressed 512KBytes with 68008s), and an 8-bit data bus. A
planned future form (later the 68020) had a 32-bit data and address
bus.
===}}}
(это с wikipedia, www.wikipedia.org/wiki/Motorola_68000)
Или через одну ссылку:
==={{{
The 68000 has 32-bit registers but only a 16-bit ALU and external data
bus. It has 24-bit addressing and a linear address space, with none of
the evil segment registers of Intel's contemporary processors that
make programming them unpleasant. That means that a single directly
accessed array or structure can be larger than 64KB in size. Addresses
are computed as 32 bit, but the top 8 bits are cut to fit the address
bus into a 64-pin package (address and data share a bus in the 40 pin
packages of the 8086 and Zilog Z8000).
The 68000 has sixteen 32-bit registers, split into data and address
registers. One address register is reserved for the Stack Pointer. Any
register, of either type, can be used for any function except direct
addressing. Only address registers can be used as the source of an
address, but data registers can provide the offset from an address.
===}}}
(burks.brighton.ac.uk/burks/foldoc/81/75.htm)
Great CPU list (www3.sk.sympatico.ca/jbayko/cpu3.html) подтверждает.
Теперь попробуй доказать, что это все не так и что авторы этих текстов
врут. ;)) Для меня вывод очевиден - 68000 следует считать 32-разрядным
процессором с точки зрения программиста.
Так что компьютерра, похоже, ошиблась только в интеловской линии.
P.S. А девушку ты ругал зря. Hадо было ругать школу, в которой она училась.
-netch-
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