moved and added docu on picoc and xv6

2 files changed, 37 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
+  
+  
diff --git a/doc/README.xv6 b/doc/README.xv6
new file mode 100644
index 0000000..c5b9395
--- /dev/null
+++ b/doc/README.xv6
@@ -0,0 +1,9 @@
+xv6 is nice, but requires gcc
+
+picoc: github.com/Prashant47/picoc
+guy had the same idea of a self-hosting and self-compiling
+cc in xv6.
+
+No perl, no make, and no funny business in the C compiler.
+One issue will be the linker. Either go back to binary or
+a.out format or using ELF (juck).