Move variables from assembler to C code.

Define macro VAR16FIXED for declaring a variable at a fixed location.
Introduce new file src/misc.c, and move non int15 calls from system.c
    to it.
Implement all fixed location variables in C code.
Move IDT/GDT defs to misc.c.  Remove unused gdt entry 1.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/disk.c b/src/disk.c
index d5c7df2..13cb1f3 100644
--- a/src/disk.c
+++ b/src/disk.c
@@ -712,3 +712,6 @@ handle_76()
     SET_BDA(disk_interrupt_flag, 0xff);
     eoi_pic2();
 }
+
+// Old Fixed Disk Parameter Table (newer tables are in the ebda).
+struct fdpt_s OldFDPT VAR16FIXED(0xe401);