Talk:Detecting Memory (x86): Difference between revisions
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:You are making the wrong assumption here: you can access all 32-bit GPRs, all 80-bits FPRs, and even the 64 and 128-bit vector registers with 16-bit code in real mode, EDX being no exception. You are even required to use a 32-bit register to enter protected mode as CR0 is 32 bits as well. The only thing real mode forbids is using segment offsets over 64KB for backwards compatibility and even that can be [[Unreal Mode|disabled]]. Your assembler will take care of the rest and insert the correct opcodes for you. - [[User:Combuster|Combuster]] 22:55, 20 January 2011 (UTC) |
:You are making the wrong assumption here: you can access all 32-bit GPRs, all 80-bits FPRs, and even the 64 and 128-bit vector registers with 16-bit code in real mode, EDX being no exception. You are even required to use a 32-bit register to enter protected mode as CR0 is 32 bits as well. The only thing real mode forbids is using segment offsets over 64KB for backwards compatibility and even that can be [[Unreal Mode|disabled]]. Your assembler will take care of the rest and insert the correct opcodes for you. - [[User:Combuster|Combuster]] 22:55, 20 January 2011 (UTC) |
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::Wow, that was a pretty boneheaded mistake. I think misreading some assembler output caused my misconception. Thank you! [[User:Surgo|Surgo]] 23:05, 20 January 2011 (UTC) |
::Wow, that was a pretty boneheaded mistake. I think misreading some assembler output caused my misconception. Thank you! [[User:Surgo|Surgo]] 23:05, 20 January 2011 (UTC) |
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== INT 0x12 == |
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The [http://www.ctyme.com/intr/rb-0598.htm RBIL] doesn't say this interrupt returns error, and it's impossible, since this function was there since the very first IBM PC computer, so there was no need to set/reset the carry flag. It's not possible for this function not to be supported. In fact, I had trouble with this and it didn't work for me until I removed the error checking. |
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[[User:Unsigned|Unsigned]] 19:15, 22 August 2015 (CDT) |
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