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От Pasha Zakharov (2:5001/3) к Alex Batishchev

Hello Alex.

19 Апр 09 11:43, Alex Batishchev wrote to Pasha Zakharov:

 AB> Hi, Pasha!

 AB> 11 Apr 09 16:34, Pasha Zakharov wrote to Pasha Zakharov:

 PZ>> исходя из логики pаботы чтение всего сектоpа целиком выполняется

 PZ>> инстpукцией пpоцессоpа LDIR,

 AB> Серьезно? Там, что, содержимое сектора отображается на обычное

 AB> адресное пространство?

однако да )

http://www.msx.ch/sunformsx/download/idetxt/idetech.html

The 16 IDE registers are mapped to address space #7E00-#7E0F? but also to

#7E10-#7E1f and also to #7E20-#7E2F? /// #7EF0-#7EFF/ But it is

recommended to use only addresses #7E00-#7E0F/

Because the Data Register is 16 bit long? it is mapped in the following

way^ each word in the address space #7C00-#7DFF is mapped onto the Data

Register/ For example? if you want to write a word to the Data Register

you can write it to address #7C00|1 or to address #7C02|3 or to address

#7C04|5? etc/ This has the following advantage^ when reading or writing

sectors from|to disk? 256 words (=512 bytes=the lenght of a sector) should

be read from|written to the Data Register/ Because the Data Register is

mapped onto the whole address space from #7C00-#7DFF? it is possible to

use a single LDIR instruction for the whole transfer operation/

Examples^

Reading from IDE device to memory^

LD HL,#7C00

LD DE,destination

LD BC,512

LDIR ;256 words are read from the Data Register

Writing from memory to IDE device^

LD HL,source

LD DE,#7C00

LD BC,512

LDIR ;256 words are written from memory to the Data Register

Pasha

--- GoldED/386 3.00.Beta3+

 * Origin: Living in interesting times (2:5001/3)

Ответы на это письмо:

From: Username
Заголовок следующего сообщения в треде может быть длинным и его придется перенести на новую строку

From: Username
Или коротким