From 9b7b65b014aa96b75b36c14d1795e2b1e8d0d2c0 Mon Sep 17 00:00:00 2001
From: "Evgeny Grechnikov (Diamond)" <diamondz@land.ru>
Date: Mon, 15 Oct 2007 14:05:52 +0000
Subject: [PATCH] acceleration of FAT writing

git-svn-id: svn://kolibrios.org@649 a494cfbc-eb01-0410-851d-a64ba20cac60
---
 kernel/trunk/fs/fat32.inc    | 12 ++++++++----
 kernel/trunk/fs/part_set.inc |  9 +++++++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/kernel/trunk/fs/fat32.inc b/kernel/trunk/fs/fat32.inc
index 15bda498fa..846456c1a3 100644
--- a/kernel/trunk/fs/fat32.inc
+++ b/kernel/trunk/fs/fat32.inc
@@ -293,7 +293,6 @@ get_FAT:
 
 get_free_FAT:
 ;-----------------------------------------------------------
-; input  : EAX = # cluster for start the searching
 ; output : if CARRY=0 EAX = # first cluster found free
 ;          if CARRY=1 disk full
 ; Note   : for more speed need to use fat_cache directly
@@ -301,10 +300,14 @@ get_free_FAT:
     push  ecx
     mov   ecx,[LAST_CLUSTER]    ; counter for full disk
     sub   ecx,2
+    mov   eax,[fatStartScan]
+    cmp   eax,2
+    jb    gff_reset
 
   gff_test:
     cmp   eax,[LAST_CLUSTER]    ; if above last cluster start at cluster 2
     jbe   gff_in_range
+  gff_reset:
     mov   eax,2
 
   gff_in_range:
@@ -328,6 +331,8 @@ get_free_FAT:
     ret
 
   gff_found:
+    lea   ecx,[eax+1]
+    mov   [fatStartScan],ecx
     pop   ecx
     clc
     ret
@@ -671,6 +676,8 @@ add_disk_free_space:
     jne   add_not_fs
 
     add   [ebx+0x1e8],ecx
+    mov   eax,[fatStartScan]
+    mov   [ebx+0x1ec],eax
     call  hd_write
 ;    cmp   [hd_error],0
 ;    jne   add_not_fs
@@ -1478,7 +1485,6 @@ fat_notroot_next_write:
         jmp     fat_notroot_next_sector
 fat_notroot_extend_dir:
         push    eax
-        mov     eax, [eax]
         call    get_free_FAT
         jnc     .found
         pop     eax
@@ -1941,7 +1947,6 @@ fs_HdRewrite:
         mov     esi, edx
         test    ecx, ecx
         jz      .done
-        mov     eax, 2
         call    get_free_FAT
         jc      .diskfull
         push    eax
@@ -2392,7 +2397,6 @@ hd_extend_file:
         jae     .extend_done
 ; add new cluster
         push    eax
-        mov     eax, edx
         call    get_free_FAT
         jc      .disk_full
         mov     edx, [fatEND]
diff --git a/kernel/trunk/fs/part_set.inc b/kernel/trunk/fs/part_set.inc
index d36bac7ead..2c4f3ac7a5 100644
--- a/kernel/trunk/fs/part_set.inc
+++ b/kernel/trunk/fs/part_set.inc
@@ -49,6 +49,8 @@ fatBAD               dd 0x0FFFFFF7
 fatEND               dd 0x0FFFFFF8
 fatMASK              dd 0x0FFFFFFF
 
+fatStartScan         dd 2
+
 fs_dependent_data_end:
 file_system_data_size = $ - PARTITION_START
 if file_system_data_size > 96
@@ -423,6 +425,7 @@ boot_read_ok:
     inc   eax
     mov   [LAST_CLUSTER],eax
     dec   eax                   ; cluster count
+    mov   [fatStartScan],2
 
     ; limits by Microsoft Hardware White Paper v1.03
     cmp   eax,4085              ; 0xff5
@@ -436,6 +439,12 @@ fat32_partition:
     movzx eax,word [ebx+0x30]   ; fs info sector
     add   eax,[PARTITION_START]
     mov   [ADR_FSINFO],eax
+    call  hd_read
+    mov   eax,[ebx+0x1ec]
+    cmp   eax,-1
+    jz    @f
+    mov   [fatStartScan],eax
+@@:
 
     popad