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2.2 KiB
ArmAsm

%define BOOT0_LOADPOINT 0x7c00
%define BOOT1_LOADPOINT 0x8200
%define MEMMAP 0x6a00
%define MEMMAP_END BOOT0_LOADPOINT
%define MEMMAP_ENT_SIZE 32
%define MEMMAP_CAP ((MEMMAP_END - MEMMAP) / MEMMAP_ENT_SIZE)
%define GLOBALS 0x4000
%define GLOBALS_END MEMMAP
%define STACK_BASE GLOBALS
%define EBDA_START 0x080000
%define VGA_SEG 0xb800
%define BOOT1_MAGIC 0x544e4150
%define VGA_WIDTH 80
%define VGA_HEIGHT 25
; ASCII string "SMAP", which is used by e820 as a magic number argument and return value.
%define E820_MAGIC 0x534d4150
; Size of entry returned by e820. This is less than MEMMAP_ENT_SIZE because we add some fields of
; our own.
%define E820_ENTRY_SIZE 24
%define MEMMAP_ENT_FIELD_BASE 0x00
%define MEMMAP_ENT_FIELD_LEN 0x08
%define MEMMAP_ENT_FIELD_TYPE 0x10
%define MEMMAP_ENT_FIELD_EXT 0x14
%define MEMMAP_ENT_FIELD_END 0x18
%define GDT_DESCRIPTOR_SIZE 0x08
; boot0 base stack frame variable offsets / globals
; (we use the same offsets once we copy the variables to the globals section)
; -------------------------------------------------------------------------------------------------
; The boot drive number given to us by the BIOS.
%define BOOT_DRIVE 0x02
; Boot drive geometry
%define SECTORS_PER_TRACK 0x04
%define N_HEADS 0x06
; Starting LBA of the GPT partition entries array.
%define GPT_ENTRIES_START_LBA 0x08
; Number of GPT entries, saturated to 16 bits.
%define GPT_N_ENTRIES_16 0x0a
; Number of sectors to advance by once we've read every GPT entry in the current sector.
%define GPT_SECTOR_STRIDE 0x0c
; Number of bytes to advance by in the current sector once we've read a GPT entry.
%define GPT_BYTE_STRIDE 0x0e
; Number of GPT entries which can fit in a single sector.
%define GPT_ENTRIES_PER_SECTOR 0x10
%define GPT_CURRENT_ENTRY_IDX 0x12
%define GPT_SECTOR_ENTRY_IDX 0x14
%define GPT_SECTORS_LOADED 0x16
%define GPT_CURRENT_LBA 0x18
%define BOOT1_GPT_ENTRY_ADDR 0x1a
; Globals
; ------------------------------------------------------------------------------------------------
%define VGA_COL 0x1c
%define TEXTBUF_LINE 0x1e
%define MEMMAP_ENTRIES 0x20