multiple updates

OperatingSystem/software/include/fat16.s

@@ -53,23 +53,6 @@ _fat_get_root_table_loop:  ; multiply
     call _fat_math_sector_add_16
     ret
 
-; reset LBA pointer to first sector in partition
-fat_reset_pointer:
-    LD HL,MEM_IDE_PARTITION
-    LD DE,MEM_IDE_POINTER
-    jr fat_copy_lba_pointer
-
-; resets LBA pointer (4-byte) to partition start
-; HL = from here
-; DE = to this destimation
-fat_copy_lba_pointer:
-    PUSH BC
-    LD B,0
-    LD C,4
-    LDIR
-    POP BC
-    ret
-
 ;-------------------------------------
 ; Print current fat directory of MEM_IDE_POINTER
 ;-------------------------------------
@@ -153,8 +136,82 @@ _fat_print_directory_loop_break_dirty
     call print_a_hex
     ld hl, [str_files]
     call print_str  ;print 
-
     ret
+
+;-------------------------------------
+; FAT locate file startcluster
+;
+; DE pointer to file name
+;-------------------------------------
+fat_lfs:
+    PUSH DE
+    LD HL,MEM_IDE_BASE + 17   ; prepare filename
+    CALL format_filename_fat16
+
+    LD A,16 ;init counter for FAT sectors
+    LD (MEM_FAT_COUNT1),A
+
+    LD HL,MEM_IDE_POINTER   ;read first sector
+    LD B,1
+    call read_lba_sector
+
+    LD HL, MEM_IDE_BUFFER   ;set buffer start
+    LD C,16                 ;set entries counter
+
+_fat_lfs_loop:
+    POP DE
+    PUSH DE
+    CALL compare_filename
+    JR C, _fat_lfs_loop_compare_match   ;on match
+
+    ; prepare next entry
+    DEC C   ;next sector after 16 entries
+    JR Z,_fat_lfs_loop_compare_next_sector
+    LD DE, 32   ;length of entry
+    ADD HL,DE   ;increment
+    JP _fat_lfs_loop
+
+_fat_lfs_loop_compare_next_sector:
+    LD H,0
+    LD L,1      
+    call _fat_math_sector_add_16 ;increment sector
+    LD A,(MEM_FAT_COUNT1)  ; decrement sector count (max FAT length)
+    DEC A
+    LD (MEM_FAT_COUNT1),A
+    JP Z, _fat_lfs_loop_compare_end ; if DE is 0, mmax is reached. End here
+    ;call print_a_hex
+
+    LD HL,MEM_IDE_POINTER   ;read next sector
+    LD B,1
+    call read_lba_sector
+
+    LD HL, MEM_IDE_BUFFER   ;set buffer start
+    LD C,16                  ;set entries counter
+    JP _fat_lfs_loop
+
+_fat_lfs_loop_compare_end:
+    POP DE
+    LD HL, [str_file_notfound] 
+    CALL print_str  ;print 
+    RET
+
+_fat_lfs_loop_compare_match:
+    ; get entry
+    POP DE
+    LD B,8
+    call print_str_fixed
+    ld A,'.'
+    call print_char
+    LD B,3
+    call print_str_fixed
+
+    LD HL, [str_file_found]
+    CALL print_str  ;print 
+    
+    RET
+
+
+
 ;=================== UTIL Functions ===========================
 ; 32 Bit addition to pointer
 ; HL has value
@@ -174,4 +231,92 @@ _fat_math_sector_add_16_2:
     LD A,1
     ADD A,(IX+1)
     LD (IX+1),A
-    RET
+    RET
+
+; reset LBA pointer to first sector in partition
+fat_reset_pointer:
+    LD HL,MEM_IDE_PARTITION
+    LD DE,MEM_IDE_POINTER
+    jr fat_copy_lba_pointer
+
+; resets LBA pointer (4-byte) to partition start
+; HL = from here
+; DE = to this destimation
+fat_copy_lba_pointer:
+    PUSH BC
+    LD B,0
+    LD C,4
+    LDIR
+    POP BC
+    ret
+
+; compares filenames
+; HL points to name1
+; DE points to name2
+; Carry is set if match
+; Destroys DE, AF
+compare_filename:
+    PUSH HL
+    PUSH BC
+    LD B, 11    ;Counter
+_compare_filename_loop:
+    LD A,(DE)
+    LD C,A
+    LD A,(HL)
+    XOR C   ;check if identical (should return 0)
+    JR NZ, _compare_filename_nomatch   
+    DEC B   ;decrement counter
+    JR NZ, _compare_filename_loop   ;if not last, continue
+    POP BC  ;if last, it matches
+    POP HL
+    SCF
+    RET
+_compare_filename_nomatch:
+    POP BC
+    POP HL
+    SCF
+    CCF
+    RET
+
+; formats filename to 8+3 format
+; DE points to source filename to string
+; HL points to destination
+format_filename_fat16:
+    LD B, 11 ;counter
+    PUSH HL
+    XOR A
+_format_filename_fat16_clean:
+    LD (HL),A
+    INC HL
+    DJNZ _format_filename_fat16_clean
+    POP HL ; continue with copy
+    LD B, 13   
+_format_filename_fat16_loop:
+    LD A, (DE)  ; load byte
+    OR A
+    RET Z ;exit on 0byte
+    DEC B                               ;reduce counter
+    RET Z ;exit after 12 bytes 8+.+3
+    CP '.' ; check if dot 
+    JR NZ, _format_filename_fat16_loop_copy ; if not continue as usual
+    INC DE  ;else skip char
+_format_filename_fat16_loop_skip_8:
+    LD A,B
+    CP 5
+    JR C, _format_filename_fat16_loop
+    INC HL
+    DEC B
+    JR _format_filename_fat16_loop_skip_8
+
+_format_filename_fat16_loop_copy:
+    LD A, (DE)  ; load byte
+    LD (HL), A  ; copy byte
+    INC HL
+    INC DE
+    JP _format_filename_fat16_loop
+
+str_file_notfound:
+    db "File not found!",13,10,0
+
+    str_file_found:
+    db " File located!",13,10,0