pushed updates
This commit is contained in:
Dennis Gunia
325
OperatingSystem/software2/include/fat16_file.s
Normal file
325
OperatingSystem/software2/include/fat16_file.s
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;1. find sector for given cluster
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;2. read sector
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;3. store first data sector to MEM_FAT_OF0_DATSEC
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;4. set MEM_FAT_OF0_DATREM to amount uf sectors per cluster
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;5. find next cluster in FAt and update MEM_FAT_OF0_CCLUST
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; gets sector in FAT table for the cluster stored in MEM_FAT_OF0_CCLUST
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; store result in MEM_FAT_OF0_FATSEC
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; stores next cluster in MEM_FAT_OF0_CCLUST
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fat_getfatsec:
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ld HL,(MEM_FAT_OF0_CCLUST) ;load cluster
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ld a,h ;if not 0x0000
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or l
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jp nz, _fat_getfatsec_notroot
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;if 0x0000, goto root directory
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ld hl,MEM_FAT_ROOTSTART
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ld de,MEM_FAT_OF0_DATSEC
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ldi ;quick and dirty hack to go back to root directory
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ldi
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ldi
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ldi
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ret
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_fat_getfatsec_notroot:
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ld HL,(MEM_FAT_OF0_CCLUST) ;load cluster
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;each sector contains 256 clusters
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;first 8bits are not needed (/256)
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ld a,h ;divide by 256
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ld l,a
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xor a
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ld h,a
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ld bc,(MEM_FAT_RESERVED) ;add reserved sectors
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add hl,bc
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ld(MEM_FAT_OF0_FATSEC+0),hl;store sector
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xor a
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ld(MEM_FAT_OF0_FATSEC+2),a
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ld(MEM_FAT_OF0_FATSEC+3),a
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call ideif_get_drv_pointer
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inc ix
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inc ix
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push ix
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pop de ;copy poiter to hl
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ld bc,[MEM_FAT_OF0_FATSEC]
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call _fat_math_add32 ;MEM_FAT_OF0_FATSEC now contains the correct sector
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;in the FAT
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;read FAT sector
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ld hl,MEM_FAT_OF0_FATSEC ;read next sector
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ld b,1
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LD DE, MEM_IDE_BUFFER ;where to store data?
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call read_lba_sector
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;calculate data sector
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;multiply cluster by length of cluster
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xor a ;clear carry
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ld a,(MEM_FAT_CLUSTERLEN)
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ld b,0
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ld c,a
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ld de,(MEM_FAT_OF0_CCLUST) ;load cluster number
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dec de ; sub 2 becaus fat starts at 3
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dec de
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call _fat_math_mul32
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; BCHL contains result -> store to PTR.MEM_FAT_OF0_DATSEC
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ld (MEM_FAT_OF0_DATSEC+0),hl
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ld (MEM_FAT_OF0_DATSEC+2),bc
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; add start of data region to addr
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ld bc,[MEM_FAT_OF0_DATSEC]
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ld de,[MEM_FAT_DATASTART]
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call _fat_math_add32 ;MEM_FAT_OF0_FATSEC now contains the correct sector
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;in the FAT
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;MEM_FAT_OF0_DATSEC now has the first sector of the selected cluster
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;reset MEM_FAT_OF0_DATREM to default cluster length
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ld a,(MEM_FAT_CLUSTERLEN)
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ld l,a
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ld h,0
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ld (MEM_FAT_OF0_DATREM), hl
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;get next cluster
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;calculate offset address
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ld a,(MEM_FAT_OF0_CCLUST)
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RLA ;shift to left (x2)
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ld l, a
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ld a,0
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RLA ;shift in carry flag
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ld h,a
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ld de,MEM_IDE_BUFFER
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add hl,de
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;copy pointer (hl to de)
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ld de,MEM_FAT_OF0_CCLUST
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ldi ;copy byte for next cluster from FAT
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ldi
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ret
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;store data
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; reads single sector of file
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; must run fat_readfilesec before to initialize
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; if a ix 0x00, success
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; if a is 0xFF, end reached
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fat_readfilesec:
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call fat_print_dbg
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ld hl,[MEM_FAT_OF0_DATSEC]
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ld b,1
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LD DE, MEM_IDE_BUFFER ;where to store data?
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call read_lba_sector ;read sectore
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ld hl,[MEM_FAT_OF0_DATSEC] ;increment pointer to next sector
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call _fat_increment_32 ;***
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ld hl,(MEM_FAT_OF0_DATREM) ;reduce counter
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xor a
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ld de,1
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sbc hl,de ;decrement counter
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ld (MEM_FAT_OF0_DATREM),hl ;store decremented counter
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ret nz ;when not zero, exit function
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;if zero:
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ld a, 0xFF ;preload error code
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ld hl,(MEM_FAT_OF0_CCLUST) ;check next chunk
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ld de,0xFFFF ;end mark
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sbc hl,de ;if Z match
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ret z ;If 0xFFFF, end is reched. Return
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;if next cluster available:
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xor a
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call fat_getfatsec ; read next cluster information
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ret
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;-------------------------------------
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; FAT open file
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;
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; DE pointer to file name
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;-------------------------------------
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fat_openfile:
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PUSH DE
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;MEM_FAT_TMPFNAME now has valid text to compare
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LD HL,[MEM_FAT_TMPFNAME]
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call format_filename_fat16
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POP DE
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fat_openfile_noprepare:
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PUSH DE
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;prepare pointer
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ld hl,MEM_FAT_CURRDIR
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ld de,MEM_IDE_POINTER
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ldi
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ldi
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ldi
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ldi
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LD A,(MEM_FAT_DIRSEC) ;init counter for FAT sectors
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LD (MEM_FAT_COUNT1),A
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LD HL,MEM_IDE_POINTER ;read first sector
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LD B,1
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LD DE, MEM_IDE_BUFFER ;where to store data?
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call read_lba_sector
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;LD HL,MEM_IDE_BUFFER ;Dump IDE Buffer
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;LD B,32
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;call dump_pretty
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;LD HL,MEM_FAT_TMPFNAME ;Dump IDE Buffer
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;LD B,1
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;call dump_pretty
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LD HL, MEM_IDE_BUFFER ;set buffer start
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LD C,16 ;set entries counter
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_fat_lfs_loop:
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LD DE,[MEM_FAT_TMPFNAME]
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CALL compare_filename
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JR C, _fat_lfs_loop_compare_match ;on match
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; prepare next entry
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DEC C ;next sector after 16 entries
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JR Z,_fat_lfs_loop_compare_next_sector
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LD DE, 32 ;length of entry
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ADD HL,DE ;increment
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JP _fat_lfs_loop
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_fat_lfs_loop_compare_next_sector:
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ld hl,[MEM_IDE_POINTER]
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call _fat_increment_32 ;increment sector
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LD A,(MEM_FAT_COUNT1) ; decrement sector count (max FAT length)
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DEC A
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LD (MEM_FAT_COUNT1),A
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JP Z, _fat_lfs_loop_compare_end ; if DE is 0, mmax is reached. End here
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;call print_a_hex
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LD HL,MEM_IDE_POINTER ;read next sector
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LD B,1
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LD DE, MEM_IDE_BUFFER ;where to store data?
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call read_lba_sector
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LD HL, MEM_IDE_BUFFER ;set buffer start
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LD C,16 ;set entries counter
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ld a,(HL)
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or a
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jp z, _fat_lfs_loop_compare_end ;skip empty sectors
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JP _fat_lfs_loop
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_fat_lfs_loop_compare_end:
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POP DE
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;LD HL, [str_file_notfound]
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;CALL print_str ;print
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ld a,0xFF
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RET
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_fat_lfs_loop_compare_match:
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; get entry
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POP DE
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; HL points to Start of Table item
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PUSH HL
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POP IX
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; get important information
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ld a,(ix+0x1B) ;first cluster number
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ld (MEM_FAT_OF0_CCLUST+1),a
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ld a,(ix+0x1A)
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ld (MEM_FAT_OF0_CCLUST+0),a
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ld a,(ix+0x0B)
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ld (MEM_FAT_OF0_ATTRIBUTE+0),a
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xor a ;clear carry ;set MEM_FAT_OF0_DATREM to remaining sectors
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ld a,(ix+0x1F) ;cluste length shift by 256
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rra
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ld (MEM_FAT_FILEREMAIN+2),a
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ld a,(ix+0x1E)
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rra
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ld (MEM_FAT_FILEREMAIN+1),a
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ld a,(ix+0x1D)
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rra
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ld (MEM_FAT_FILEREMAIN+0),a
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ld a,0
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ld (MEM_FAT_FILEREMAIN+3),a
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call fat_getfatsec ;get sector information
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;call print_newLine
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;LD B,8
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;call print_str_fixed
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;ld A,'.'
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;call print_char
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;LD B,3
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;call print_str_fixed
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;LD HL, [str_file_found]
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;CALL print_str ;print
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xor a
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RET
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; compares filenames
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; HL points to name1
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; DE points to name2
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; Carry is set if match
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; Destroys DE, AF
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compare_filename:
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PUSH HL
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push BC
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LD B, 11 ;Counter
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_compare_filename_loop:
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LD A,(DE)
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LD C,A
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LD A,(HL)
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INC HL
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INC DE
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XOR C ;check if identical (should return 0)
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JR NZ, _compare_filename_nomatch
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djnz _compare_filename_loop ;if not last, continue
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POP BC
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POP HL
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SCF
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RET
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_compare_filename_nomatch:
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POP BC
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POP HL
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XOR A ; clear carry flag
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RET
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; formats filename to 8+3 format
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; DE points to source filename to string
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; HL points to destination
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format_filename_fat16:
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LD B, 11 ;counter
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PUSH HL
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LD A, ' '
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_format_filename_fat16_clean:
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LD (HL),A
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INC HL
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DJNZ _format_filename_fat16_clean
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POP HL ; continue with copy
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LD B, 13
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_format_filename_fat16_loop:
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LD A, (DE) ; load byte
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OR A
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RET Z ;exit on 0byte
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DEC B ;reduce counter
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RET Z ;exit after 12 bytes 8+.+3
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CP '.' ; check if dot
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JR NZ, _format_filename_fat16_loop_copy ; if not continue as usual
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INC DE ;else skip char
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_format_filename_fat16_loop_skip_8:
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LD A,B
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CP 5
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JR C, _format_filename_fat16_loop
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INC HL
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DEC B
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JR _format_filename_fat16_loop_skip_8
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_format_filename_fat16_loop_copy:
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LD A, (DE) ; load byte
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LD (HL), A ; copy byte
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INC HL
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INC DE
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JP _format_filename_fat16_loop
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str_file_notfound:
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db "File not found!",13,10,0
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str_file_found:
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db " File located!",13,10,0
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