TempleOS V5.03 Nightly (ISO SHA-1 aed1efc)

Doc/MemOverview.DD

@@ -8,7 +8,7 @@ You can create new, independent heaps using $LK,"HeapCtrlInit",A="MN:HeapCtrlIni
 
 Memory alloced by a task will be freed when the task is killed.  The $LK,"Adam Task",A="FF:::/Doc/Glossary.DD,Adam Task"$ is a task that never dies.  His memory is like kernel memory in other operating systems.  See $LK,"ACAlloc",A="MN:ACAlloc"$(), $LK,"AMAlloc",A="MN:AMAlloc"$(), $LK,"AMAllocIdent",A="MN:AMAllocIdent"$() and $LK,"AStrNew",A="MN:AStrNew"$().
 
-All of the regular page tables are marked, "cached".  When accessing hardware, however, you need uncached page table.  The lowest 4Gig addresses have an alias to access hardware located toward the top of mapped space, $FG,2$0x$TX,"01AA000000",D="DD_UNCACHED_ALIAS"$$FG$.  See $LK,"dev.uncached_alias",A="FF:::/Kernel/KEnd.HC,dev.uncached_alias"$.
+All of the regular page tables are marked, "cached".  When accessing hardware, however, you need uncached page table.  The lowest 4Gig addresses have an alias to access hardware located toward the top of mapped space, $FG,2$0x$TX,"01AA000000",D="DD_UNCACHED_ALIAS"$$FG$.  See $LK,"dev.uncached_alias",A="FF:::/Kernel/KMain.HC,dev.uncached_alias"$.
 
 During an extended powered-on session of TempleOS, in theory, memory will become fragmented, requiring a reboot.  It has never happens to me.
 
@@ -55,8 +55,8 @@ In 2003, I wanted to make a no-paging ring-0-only 64-bit operating system for su
 
 I needed VGA A0000-BFFFF memory to be write-through and 0xE0000000-0xFFFFFFFF to be uncached for various devices.  All 64-bit computers allow stopping address translation at 2Meg page size, not using 4K.  I wanted to use 2Meg for everything because it's faster, with one less level of page tables.  I had to make A0000-BFFFF write-through, though, so I could not use 2Meg size on the lowest page.  I did the lowest 2Meg area as 4K pages.  I also unmapped the first 4K to cause a fault when dereferencing NULL.
 
-In 2016, I came-up with an alternate idea.  I double mapped the lowest memory with an alias that was uncached.  Accessing the lowest 2Meg area directly was cached but the alias I created up at the top of address space was uncached.  See $LK,"UncachedAliasAlloc",A="MN:UncachedAliasAlloc"$().  Unfortunately, I could no longer boast of the simplicity of identity mapping everything.  Since many of my users are familiar with A0000-BFFFF, it is actually pretty seriously unfortunate that they cannot use the easy-to-understand numbers of A0000-BFFFF, but must access the relocated alias location.  See $LK,"text.vga_alias",A="FF:::/Kernel/KEnd.HC,text.vga_alias"$.  I also no longer cause a fault when dereferencing NULL.
+In 2016, I came-up with an alternate idea.  I double mapped the lowest memory with an alias that was uncached.  Accessing the lowest 2Meg area directly was cached but the alias I created up at the top of address space was uncached.  See $LK,"UncachedAliasAlloc",A="MN:UncachedAliasAlloc"$().  Unfortunately, I could no longer boast of the simplicity of identity mapping everything.  Since many of my users are familiar with A0000-BFFFF, it is actually pretty seriously unfortunate that they cannot use the easy-to-understand numbers of A0000-BFFFF, but must access the relocated alias location.  See $LK,"text.vga_alias",A="FF:::/Kernel/KMain.HC,text.vga_alias"$.  I also no longer cause a fault when dereferencing NULL.
 
 Then, I switched to 1Gig page sizes.  For the lowest 4Gig, I set-up an alias up at the top of address space.  See $LK,"UncachedAliasAlloc",A="MN:UncachedAliasAlloc"$().  Not all computers support 1Gig page tables, however, so I also support 2Meg.
 
-My original plan was to allow changing the page tables as needed, so I had code for taking control of 2Meg pages and marking them uncached or whatever.  When I did a HDAudio driver, I requested some 32-bit address space as uncached.  Today, all of the first 4Gig can be accessed without caching at the $LK,"dev.uncached_alias",A="FF:::/Kernel/KEnd.HC,dev.uncached_alias"$.
+My original plan was to allow changing the page tables as needed, so I had code for taking control of 2Meg pages and marking them uncached or whatever.  When I did a HDAudio driver, I requested some 32-bit address space as uncached.  Today, all of the first 4Gig can be accessed without caching at the $LK,"dev.uncached_alias",A="FF:::/Kernel/KMain.HC,dev.uncached_alias"$.