📄 fat32.inc
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; FAT32.INC ;;
;; ;;
;; FAT32 functions for MenuetOS ;;
;; ;;
;; Copyright 2002 Paolo Minazzi, paolo.minazzi@inwind.it ;;
;; ;;
;; See file COPYING for details ;;
;; ;;
;; 10.9.2004 Fat16 file system - Mario79 ;;
;; 06.9.2004 Fix free space by Mario79 added - MH ;;
;; 24.5.2004 Write back buffer for File_write - VT ;;
;; 20.5.2004 File_read function to work with syscall 58 - VT ;;
;; 30.3.2004 Error parameters at function return - VT ;;
;; 01.5.2002 Bugfix in device write - VT ;;
;; 20.5.2002 Hd status check - VT ;;
;; 29.6.2002 Improved fat32 verification - VT ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; CLUSTER[0] CLUSTER[1] CLUSTER[2] CLUSTER[3]
;
;### ######## -->######## -->######## ########
;#2#--> # # | # # | # # # #
;### # # | # # | # # # #
; # # | # # | # # # #
; # # | # # | # # # #
; # # | # # | # # # # CLUSTER
; # # | # # | # # # #
; # # | # # | # # # #
; # # | # # | # # # #
; ######## | ######## | ######## ########
; | |
; | ------------------
; | |
; -------------------- |
; | |
; ######## ######## ######## ########
; # xxxx # # xxxx # # 3 # # 4 #
; ######## ######## ######## ######## FAT
;
; FAT[0] FAT[1] FAT[2] FAT[3]
;
cache_max equ 1000
RESERVED_SECTOR: dd 0x20
PARTITION_START: dd 0x3f
FAT32_SIZE: dd 0x1f3a
NUMBER_OF_FATS: dd 0x2
SECTOR_PER_CLUSTER: dd 0x8
ROOT_CLUSTER: dd 2
buffer: times 64 dd 0,0
cluster: dd 0
cluster1: dd 0
valid_fat: db 0
PARTITION_SIZE: dd 0
PARTITION_END: dd 0
hd_error dd 0
hd_setup dd 0
;***********************
;* Start *
;* Mario79 edited code *
;* correct free mem *
;* change 1.1 *
;***********************
FILE_SIZE: dd 0
ADR_FSINFO: dd 0
change_mem db 0
old_size_file: dd 0
;***********************
;* End *
;* Mario79 edited code *
;* correct free mem *
;* change 1.1 *
;***********************
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.1 *
;***********************
fs_type dd 0
file_or_directory dd 0
analyze_f16 db 0
correct_fat16 dd 0
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.1 *
;***********************
reserve_hd1:
push eax
mov eax,[0x3000]
imul eax,32
add eax,0x3000
mov eax,[eax+4]
mov [hd1_status],eax
pop eax
ret
clear_hd_cache:
pusha
mov edi,0x600000
mov ecx,65535
mov eax,0
cld
rep stosb
popa
ret
set_FAT32_variables:
cli
cmp [hd1_status],0
je set_fat32_l1
sti
call change_task
jmp set_FAT32_variables
set_fat32_l1:
call reserve_hd1
sti
call clear_hd_cache
cmp dword [hdpos],0
je problem_hd_or_partition_or_fat32_ret
push eax
push ebx
xor eax,eax ; Read MBR
mov ebx,buffer
call hd_read
cmp dword [fat32part],0
jnz hd_and_partition_ok
problem_hd_or_partition_or_fat32:
pop ebx
pop eax
problem_hd_or_partition_or_fat32_ret:
mov [valid_fat],byte 0
mov [hd1_status],0 ; free
ret
hd_and_partition_ok:
mov ecx,[fat32part]
mov eax,0
mov ebx,buffer+0x1be+8 -16
hdapl1:
add ebx,16
add eax,[ebx]
loop hdapl1
mov [PARTITION_START],eax
mov ebx,[ebx+4]
mov [PARTITION_SIZE],ebx
mov [hd_setup],1
mov ebx,buffer
call hd_read ;_new ; Read boot sector of partition
mov [hd_setup],0
cmp [ebx+0x53],dword 'AT32'
; jnz problem_hd_or_partition_or_fat32
jnz problem_hd_or_partition_or_fat32_1
mov [valid_fat],byte 1
movzx eax,word [ebx+0xe]
mov [RESERVED_SECTOR],eax
mov eax,[ebx+0x24]
mov [FAT32_SIZE],eax
movzx eax,byte [ebx+0x10]
mov [NUMBER_OF_FATS],eax
movzx eax,byte [ebx+0xd]
mov [SECTOR_PER_CLUSTER],eax
mov eax,[ebx+44]
mov [ROOT_CLUSTER],eax
mov eax,[PARTITION_START]
add eax,[PARTITION_SIZE]
dec eax
mov [PARTITION_END],eax
pop ebx
pop eax
; mov [hd1_status],0 ; free
; ret
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.2 *
;***********************
mov [fs_type],1 ; 1 -Fat32
mov [hd1_status],0 ; free
ret
problem_hd_or_partition_or_fat32_1:
cmp [ebx+55],dword 'AT16'
je par_fat16
jmp problem_hd_or_partition_or_fat32
par_fat16:
mov [valid_fat],byte 1
movzx eax,word [ebx+0xe]
mov [RESERVED_SECTOR],eax
movzx eax,word [ebx+0x16]
mov [FAT32_SIZE],eax
movzx eax,byte [ebx+0x10]
mov [NUMBER_OF_FATS],eax
movzx eax,byte [ebx+0xd]
mov [SECTOR_PER_CLUSTER],eax
xor eax,eax
mov [ROOT_CLUSTER],eax
mov eax,[PARTITION_START]
add eax,[PARTITION_SIZE]
dec eax
mov [PARTITION_END],eax
mov eax,[SECTOR_PER_CLUSTER]
shl eax,1
mov ebx,32
sub ebx,eax
mov [correct_fat16],ebx
pop ebx
pop eax
mov [fs_type],2 ; 2 - Fat16
mov [hd1_status],0 ; Free
ret
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.2 *
;***********************
set_FAT:
;--------------------------------
; set_FAT
;
; input : EAX = #block
; EDX = value to save
; output: nothing
;--------------------------------
push eax ; [esp+16]
push ebx ; [esp+12]
push ecx ; [esp+8]
push edx ; [esp+4]
push esi ; [esp]
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.3 *
;***********************
cmp [fs_type],1
je correct3_11
shl eax,1
jmp correct3_12
correct3_11:
shl eax,2
correct3_12:
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.3 *
;***********************
xor edx,edx
mov ebx,512
div ebx
mov esi,edx
add eax,[RESERVED_SECTOR]
add eax,[PARTITION_START]
mov ebx,buffer
mov ecx,[NUMBER_OF_FATS]
mov edx,[esp+4]
set_an_other_FAT:
call hd_read ;_new
cmp [f_del],1
je fat_zero
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.4 *
;***********************
cmp [fs_type],1
je correct3_11_1
cmp [buffer+esi],word 0
je fat_zero
jmp correct3_12_1
correct3_11_1:
cmp [buffer+esi],dword 0
je fat_zero
correct3_12_1:
mov [8*0x100000],dword 0xffffff
jmp fat_nonzero
fat_zero:
cmp [fs_type],1
je correct3_13_3
mov [buffer+esi],dx
jmp correct3_13_4
correct3_13_3:
mov [buffer+esi],edx
correct3_13_4:
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.4 *
;***********************
call hd_write_new
fat_nonzero:
add eax,[FAT32_SIZE]
loop set_an_other_FAT
pop esi
pop edx
pop ecx
pop ebx
pop eax
ret
get_FAT:
;--------------------------------
; get_FAT
;
; input : EAX = #block
; output: EAX = #block
;--------------------------------
push ebx
push edx
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.5 *
;***********************
cmp [fs_type],1
je correct3_13_5
shl eax,1
jmp correct3_14_1
correct3_13_5:
shl eax,2
correct3_14_1:
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.5 *
;***********************
xor edx,edx
mov ebx,512
div ebx
add eax,[RESERVED_SECTOR]
add eax,[PARTITION_START]
mov ebx,buffer
call hd_read ;_new
mov eax,[buffer+edx]
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.6 *
;***********************
cmp [fs_type],1
je correct3_13_6
and eax,0xffff
correct3_13_6:
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.6 *
;***********************
pop edx
pop ebx
ret
get_FAT_cache:
;--------------------------------
; get_FAT_cache - used for reading only : internal cache
;
; input : EAX = #block
; output: EAX = #block
;--------------------------------
push ebx
push edx
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.7 *
;***********************
cmp [fs_type],1
je correct3_13
shl eax,1
jmp correct3_14
correct3_13:
shl eax,2
correct3_14:
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.7 *
;***********************
xor edx,edx
mov ebx,512
div ebx
add eax,[RESERVED_SECTOR]
add eax,[PARTITION_START]
mov ebx,fat_cache
cmp eax,[fat_in_cache]
je fat_found_in_cache
mov [fat_in_cache],eax
call hd_read
fat_found_in_cache:
mov eax,[fat_cache+edx]
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.8 *
;***********************
cmp [fs_type],1
je correct3_13_1
and eax,0xffff
correct3_13_1:
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.8 *
;***********************
pop edx
pop ebx
ret
fat_in_cache dd -1
fat_cache: times 512 db 0
;find_pointer_in_FAT:
;--------------------------------
; For each item of FAT do
; if (item read == EAX)
; return #item
; carry=0
; else
; carry=1;
;
; input : EAX = #block
; output: if CARRY=0 then EAX = #block
; if CARRY=1 then EAX = distroyed
;--------------------------------
; add eax,2
; push eax
; push ecx
; push edx
; mov ecx,[FAT32_SIZE]
; shl ecx,9-2 ; *512 for sector /4 for dword
; mov edx,2
;adr78:
; mov eax,edx
; call get_FAT
; cmp eax,[esp+8]
; je found_pointer
; inc edx
; loop adr78
; pop edx
; pop ecx
; add esp,4
; stc
; ret
;found_pointer:
; mov eax,edx
; pop edx
; pop ecx
; add esp,4
; clc
; ret
analyze_directory:
;--------------------------------
; input : EAX = first cluster of the directory
; EBX = pointer to filename
; output : IF CARRY=0 EAX = sector where th file is found
; EBX = pointer in buffer
; [buffer .. buffer+511]
; ECX,EDX,EDI,EDI not changed
; IF CARRY=1
;--------------------------------
push ebx ;[esp+16]
push ecx
push edx
push esi
push edi
adr56:
mov [cluster_tmp],eax
mov ecx,[FAT32_SIZE]
imul ecx,[NUMBER_OF_FATS]
add ecx,[RESERVED_SECTOR]
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.9 *
;***********************
cmp [fs_type],2
je correct2_11
sub eax,2
correct2_11:
imul eax,[SECTOR_PER_CLUSTER]
cmp [fs_type],1
je correct2_13
cmp [file_or_directory],0
je correct2_13
cmp [analyze_f16],0
je correct2_13
add eax,[correct_fat16]
correct2_13:
;***********************
;* End *
;* Mario79 edited code *
;* Fat16 *
;* change 1.9 *
;***********************
add eax,[PARTITION_START]
add eax,ecx
mov edx,[SECTOR_PER_CLUSTER]
new_sector_in_cluster:
mov ebx,buffer
call hd_read ;_new
mov ecx,512/32
adr1_analyze:
mov edi,[ebx+11]
and edi,0xf
cmp edi,0xf
je long_filename_data
mov esi,[esp+16]
mov edi,ebx
cld
push ecx
mov ecx,11
rep cmpsb
pop ecx
je found_file_analyze
long_filename_data:
add ebx,32
loop adr1_analyze
inc eax
dec edx
jne new_sector_in_cluster
mov eax,[cluster_tmp]
call get_FAT
mov [cluster_tmp],eax
;***********************
;* Start *
;* Mario79 edited code *
;* Fat16 *
;* change 1.10 *
;***********************
cmp [fs_type],2
je correct5_2
cmp eax,0x0f000000
jb adr56
correct6_2:
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