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author | Andreas Baumann <mail@andreasbaumann.cc> | 2017-04-27 13:46:59 +0200 |
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committer | Andreas Baumann <mail@andreasbaumann.cc> | 2017-04-27 13:46:59 +0200 |
commit | 55fe269eaa3bd3f63b8672119aa1e96ae30f26db (patch) | |
tree | 21255fd990a2001e9bf7a91e7144f76947bd14e8 /doc/README.Wyoos | |
parent | a7fb48922dee006339747d128d83fafbe9dfe79a (diff) | |
download | abaos-55fe269eaa3bd3f63b8672119aa1e96ae30f26db.tar.gz abaos-55fe269eaa3bd3f63b8672119aa1e96ae30f26db.tar.bz2 |
moved and added docu on picoc and xv6
Diffstat (limited to 'doc/README.Wyoos')
-rw-r--r-- | doc/README.Wyoos | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/doc/README.Wyoos b/doc/README.Wyoos new file mode 100644 index 0000000..fa96fc8 --- /dev/null +++ b/doc/README.Wyoos @@ -0,0 +1,28 @@ +IDT interupt descriptor table + +GDT global descriptor table +- set up segments +- code segments, RX, never W +- data segments, RW, never X +- 16-bit compatibility on Intel, so quite a nightmare +- asm( LGDT ) needed +=> we do GTD all in assembly, not really readable! Ideal would be to + do as much as possible in C/C++ (even with some zero-overhead + C++17 crazyness maybe) and then call a pure assembly function with + a pointer to the GTD doing the 'LGDT' assembly operation + +types: +- have local typedefs for DWORD32 or uint32_t (as Windows and POSIX did + it) + +keyboard: +- 0x20 PIC +- asm( outb( port, byte)), outb function => better have ports knowing + their own bandwith. + SlowPort8, slowing down assembly code + +interrupts: +- assember stubs translating calling conventions to static C++ function + handling the interrupt number NO + + |