--- /dev/null
+; Definitions for use in GeekOS boot code
+; Copyright (c) 2001, David H. Hovemeyer <daveho@cs.umd.edu>
+; $Revision: 1.1 $
+
+; This is free software. You are permitted to use,
+; redistribute, and modify it as specified in the file "COPYING".
+
+; A lot of this code is adapted from Kernel Toolkit 0.2
+; and Linux version 2.2.x, so the following copyrights apply:
+
+; Copyright (C) 1991, 1992 Linus Torvalds
+; modified by Drew Eckhardt
+; modified by Bruce Evans (bde)
+; adapted for Kernel Toolkit by Luigi Sgro
+
+%ifndef DEFS_ASM
+%define DEFS_ASM
+
+; BIOS loads the boot sector at offset 0 in this segment
+BOOTSEG equ 0x07C0
+
+; We'll move the boot sector up to higher memory.
+; Note that the "ISA hole" begins at segment 0xA000 == 640K.
+INITSEG equ 0x9000
+
+; Put the setup code here, just after the boot sector.
+SETUPSEG equ 0x9020
+
+; Load our "Kernel" at this segment, which starts at 64K.
+; The number of sectors in the kernel, NUM_KERN_SECTORS,
+; will be passed on the command line.
+KERNSEG equ 0x1000
+ ;
+
+; Size of PFAT boot record.
+; Keep up to date with <geekos/pfat.h>.
+PFAT_BOOT_RECORD_SIZE equ 28
+
+; Offset of BIOS signature word in boot sector.
+BIOS_SIGNATURE_OFFSET equ 510
+
+; Offset of PFAT boot record in boot sector.
+PFAT_BOOT_RECORD_OFFSET equ BIOS_SIGNATURE_OFFSET - PFAT_BOOT_RECORD_SIZE
+
+; Video memory segment
+VIDSEG equ 0xb800
+
+; The following information is correct for a 1.44M floppy.
+; Yes, I'm hard coding this.
+SECTORS_PER_TRACK equ 18
+HEADS equ 2
+CYLINDERS equ 80
+
+; 8259A PIC initialization codes.
+; Source: Linux bootsect.S, and Intel 8259A datasheet
+
+; The most important reason why we reprogram the PICs is to
+; route the hardware interrupts through vectors *above*
+; those reserved by Intel. The BIOS (for historical reasons :-)
+; routes them such that they conflict with internal processor-generated
+; interrupts.
+
+ICW1 equ 0x11 ; ICW1 - ICW4 needed, cascade mode, interval=8,
+ ; edge triggered. (I think interval is irrelevant
+ ; for x86.)
+ICW2_MASTER equ 0x20 ; put IRQs 0-7 at 0x20 (above Intel reserved ints)
+ICW2_SLAVE equ 0x28 ; put IRQs 8-15 at 0x28
+ICW3_MASTER equ 0x04 ; IR2 connected to slave
+ICW3_SLAVE equ 0x02 ; slave has id 2
+ICW4 equ 0x01 ; 8086 mode, no auto-EOI, non-buffered mode,
+ ; not special fully nested mode
+
+; Kernel code and data segment selectors.
+; Keep these up to date with defs.h.
+KERNEL_CS equ 1<<3 ; kernel code segment is GDT entry 1
+KERNEL_DS equ 2<<3 ; kernel data segment is GDT entry 2
+
+; Pages for context object and stack for initial kernel thread -
+; the one we construct for Main(). Keep these up to date with defs.h.
+; We put them at 1MB, for no particular reason.
+KERN_THREAD_OBJ equ 4096
+KERN_STACK equ KERN_THREAD_OBJ + 4096
+
+%endif
