[TOOLCHAIN] Setup for emulation

README.md

@@ -19,3 +19,27 @@ automatically if you install homebrew. The rest of the packages can be
 installed with homebrew. You'll also want homebrews ctags.
 
     homebrew install gmp mpfr libmpc ctags
+
+In order to build the boot disk and run the emulator you'll need xorriso and
+qemu - also installable by homebrew.
+
+    homebrew install xorriso qemu
+
+
+A note on qemu and compatibility
+--------------------------------
+I have had great trouble with qemu, gdb and the x86_64 structure in cobination.
+For now, everything seem to work in the setup I'm using if the installed
+version of qemu is commit: a470b33259bf82ef2336bfcd5d07640562d3f63b built with
+--enable-curses.
+You may need to remove the check for wide character support in the qemu
+./configure file if building under OSX with homebrew (e.g. by deleting lines:
+2953, 2954, 2956, 2957, 2958)
+
+This is tested for GDB 7.12.
+
+Among the problems that may arise if wrong versions are used are:
+
+- g-packet something something too large in gdb
+- gdb thinking sizeof(void *) == 4 even in 64 bit mode, meaning no variables can be viewed, because their addresses are truncated to 32 bits
+- qemu crashing when a keyboard irq is received