https://wiki.friendos.dev/index.php?action=history&feed=atom&title=IA32_Manual_ConventionsIA32 Manual Conventions - Revision history2026-05-19T08:55:13ZRevision history for this page on the wikiMediaWiki 1.38.4https://wiki.friendos.dev/index.php?title=IA32_Manual_Conventions&diff=108&oldid=prevTheCatgirls: Add to x86 category2024-12-19T15:09:27Z<p>Add to x86 category</p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Puts [[Segment Selector]] with [[Requested Priviledge Level|RPL]]=0 into the ''second'' (2, 0b10, 0x2) entry of the ''[[Global Descriptor Table|GDT]]'', with the 1 being the 4th bit aka bit 3 into the [[Code Segment Register|CS register]].</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Puts [[Segment Selector]] with [[Requested Priviledge Level|RPL]]=0 into the ''second'' (2, 0b10, 0x2) entry of the ''[[Global Descriptor Table|GDT]]'', with the 1 being the 4th bit aka bit 3 into the [[Code Segment Register|CS register]].</div></td></tr>
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</table>TheCatgirlshttps://wiki.friendos.dev/index.php?title=IA32_Manual_Conventions&diff=102&oldid=prevTheCatgirls: Initial description of some IA32 manual conventions2024-12-19T00:49:30Z<p>Initial description of some IA32 manual conventions</p>
<p><b>New page</b></p><div>Bit number 0 is the first, [[Least Significant Bit]].<br />
Bit ranges are written inclusive. Example with [[Segment Selector|Segment Selectors]]:<br />
<br />
[[File:Segment_Selectors_Screenshot_01.png|800px]]<br />
<br />
Bit 0 is the least significant bit, bit 15 is the [[Most Significant Bit]]. Range "bits 3 through 15" ''include'' bit 3 and bit 15 and are 13 bits long, with bit 0 through 1 aka bit 0 and 1 being the [[Requested Priviledge Level|RPL]] and bit 2 (3rd bit) being the [[Table Indicator|TI]].<br />
Additionally, in memory, this is stored [[Little Endian]], so the least significant half of the index + 3 bits for the flags is in the first byte and the most significant half of the index is in the second byte. <br />
Do note that eg. [[NASM]] treats <code>0b</code> as numeric literals, so it'll swap the bytes around - Thus, <br />
<pre><br />
mov ax, 0000_0000_0000_1000b<br />
mov cs, ax<br />
</pre><br />
Puts [[Segment Selector]] with [[Requested Priviledge Level|RPL]]=0 into the ''second'' (2, 0b10, 0x2) entry of the ''[[Global Descriptor Table|GDT]]'', with the 1 being the 4th bit aka bit 3 into the [[Code Segment Register|CS register]].</div>TheCatgirls