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Author Topic: Debugger message "near"  (Read 2159 times)

Robz

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Debugger message "near"
« on: December 01, 2015, 02:19:21 am »
HI,

I have a stupid question; what does the Lazarus debugger message "near" mean? The last time I heard "near" was in the context of "far and near". At that time, address space was limited to 16 bits, with a four (?) bit extension yielding a 20 bit total address. A far and near code page command made the switch. 32 bit processors eliminated the need for far and near, but a few interests insisted on using far and near terms on 32 and above processors. Just wondering; is far and near back?
Thanks

balazsszekely

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Re: Debugger message "near"
« Reply #1 on: December 01, 2015, 09:13:50 am »
According to the documentation near and far are unsupported  modifiers.
Quote
The reason why these modifiers are not supported is that these modifiers deal with 16 bit code for DOS. In other words, these modifiers have special meaning for 16 bit programming under DOS and Windows 3.x. As Free Pascal does not support 16 bit code (only 32 and 64 bit), these modifiers are irrelevant in Free Pascal code.

Note: However, these modifiers are supported in the DOS crosscompiler present in the FPC development version.

marcov

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Re: Debugger message "near"
« Reply #2 on: December 01, 2015, 12:10:25 pm »
Sometimes in assembler there are short ways to encode (using a displacement) or an (long) absolute address. That is sometimes also called near and far. (or short/long as in "jmp short x" and "jmp long x").

It might echo some of such GDB (debugger) jargon back.

 

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