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refactor(boot): create fat_read_bpb func

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d0p1 🏳️‍⚧️ 2024-07-29 17:51:41 +02:00
parent 899e456249
commit e0ab3e5c1a
3 changed files with 33 additions and 24 deletions
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1
boot/loader/Makefile
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@ -5,6 +5,7 @@ LOADER_SRCS = loader.asm \
../common/bootinfo.inc \
../../kernel/sys/bootinfo.inc \
../../kernel/sys/register.inc \
fat.inc \
video.inc \
memory.inc \
logger.inc \

30
boot/loader/fat.inc Normal file
View file

@ -0,0 +1,30 @@
;; File: fat.inc
include '../common/fat12.inc'
fat_read_bpb:
mov ax, DISK_BUFFER/0x10
mov es, ax
xor bx, bx
mov ax, 0
mov cx, 1
call disk_read_sectors
mov word ax, [DISK_BUFFER + fat_bpb.sects_per_track]
mov word [sectors_per_track], ax
mov word ax, [DISK_BUFFER + fat_bpb.heads_per_cyl]
mov word [heads_per_cylinder], ax
mov word ax, [DISK_BUFFER + fat_bpb.bytes_per_sects]
mov word [bytes_per_sector], ax
mov word ax, [DISK_BUFFER + fat_bpb.sects_per_FAT]
mov word [sectors_per_FAT], ax
mov byte al, [DISK_BUFFER + fat_bpb.FAT_count]
mov byte [FAT_count], al
mov word ax, [DISK_BUFFER + fat_bpb.reserved_sects]
mov word [reserved_sectors], ax
mov word ax, [DISK_BUFFER + fat_bpb.root_dir_entries]
mov word [root_dir_entries], ax
mov byte al, [DISK_BUFFER + fat_bpb.sects_per_clust]
mov byte [sectors_per_cluster], al
ret

26
boot/loader/loader.asm
View file

@ -80,29 +80,7 @@ _start:
; for now fat12 is asumed
.fat_fallback:
; get bpb
mov ax, DISK_BUFFER/0x10
mov es, ax
xor bx, bx
mov ax, 0
mov cx, 1
call disk_read_sectors
mov word ax, [DISK_BUFFER + fat_bpb.sects_per_track]
mov word [sectors_per_track], ax
mov word ax, [DISK_BUFFER + fat_bpb.heads_per_cyl]
mov word [heads_per_cylinder], ax
mov word ax, [DISK_BUFFER + fat_bpb.bytes_per_sects]
mov word [bytes_per_sector], ax
mov word ax, [DISK_BUFFER + fat_bpb.sects_per_FAT]
mov word [sectors_per_FAT], ax
mov byte al, [DISK_BUFFER + fat_bpb.FAT_count]
mov byte [FAT_count], al
mov word ax, [DISK_BUFFER + fat_bpb.reserved_sects]
mov word [reserved_sectors], ax
mov word ax, [DISK_BUFFER + fat_bpb.root_dir_entries]
mov word [root_dir_entries], ax
mov byte al, [DISK_BUFFER + fat_bpb.sects_per_clust]
mov byte [sectors_per_cluster], al
call fat_read_bpb
call fat_load_root
@ -177,7 +155,7 @@ _start:
include 'a20.inc'
include '../common/bios.inc'
include '../common/fat12.inc'
include 'fat.inc'
include 'disk.inc'
include 'logger.inc'
include 'memory.inc'