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theme | Eclipse |
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title | CRC_FILE, Iterate CRC-32 on complete RAM file (from file pointer until EOF), using OS_Mv |
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OZ GN_Crc - RST 20H, DEFW $7C09
IN:
A = CRC_FILE (1)
HL = pointer to file buffer (local memory)
BC = buffer size
DE = 0, Initialize CRC-32 with FFFFFFFFh
DE > 0, (local) pointer to initial 4-byte CRC-32
IX = file handle of open file (using GN_Opf)
OUT, if call successful:
Fc = 0,
DEBC = CRC-32
OUT, if call failed:
Fc = 1,
A = RC_BAD ($04) - bad argument
A = RC_xxx (file & handle related errors)
Registers changed after return:
......HL/IXIY same
AFBCDE../.... different
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theme | Eclipse |
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title | Iterate CRC-32 partially on RAM file (from file pointer onwards), using OS_Gb |
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OZ GN_Crc - RST 20H, DEFW $7C09
IN:
A = CRC_PARTFILEBYTE (2)
HL = max bytes to read for this partial scan, or -1 for rest of file
DEBC = Initial CRC-32 or input from result of previous partial CRC-32 scan
IX = file handle of open file (using GN_Opf)
OUT, if call successful:
Fc = 0
DEBC = partial CRC-32 result (DE = high-word, BC = low-word), to be used for next scan iteration
Fc = 1, A _RC_Eof
DEBC = final CRC-32 result (DE = high-word, BC = low-word)
OUT, if call failed:
Fc = 1,
A = RC_BAD ($04) - bad argument
A = RC_xxx (file & handle related errors)
Registers changed after return:
......HL/IXIY same
AFBCDE../.... different
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theme | Eclipse |
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title | Iterate CRC-32 partially (buffered) on RAM file (from file pointer onwards), using OS_Mv |
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OZ GN_Crc - RST 20H, DEFW $7C09
IN:
A = CRC_PARTFILEBUF (3)
HL = pointer to file buffer (local memory),
BC = buffer size
DE = 0, Initialize CRC-32 with FFFFFFFFh
DE > 0, (local) pointer to 4-byte CRC-32 (initial CRC-32 or input from result of previous partial scan)
IX = file handle of open file (using GN_Opf)
OUT, if call successful:
Fc = 0
DEBC = partial CRC-32 result (DE = high-word, BC = low-word), to be used for next scan iteration
Fc = 1, A _RC_Eof
DEBC = final CRC-32 result (DE = high-word, BC = low-word)
OUT, if call failed:
Fc = 1,
A = RC_BAD ($04) - bad argument
A = RC_xxx (file & handle related errors)
Registers changed after return:
......HL/IXIY same
AFBCDE../.... different
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theme | Eclipse |
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title | Iterate CRC-32 on complete File Entry (File Card) |
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OZ GN_Crc - RST 20H, DEFW $7C09
IN:
A = CRC_EPFILE (4)
BHL = pointer to file entry
DE = 0, Initialize CRC-32 with FFFFFFFFh
DE > 0, (local) pointer to initial 4-byte CRC-32
OUT, if call successful:
Fc = 0,
DEBC = CRC-32
OUT, if call failed:
Fc = 1,
A = RC_BAD ($04) - bad argument
A = RC_xxx (file card related errors)
Registers changed after return:
......HL/IXIY same
AFBCDE../.... different |
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theme | Eclipse |
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title | Iterate CRC-32 partially on File Entry (File Card) |
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OZ GN_Crc - RST 20H, DEFW $7C09
IN:
A = CRC_PARTEPFILE (5)
Initial call:
BHL = pointer to File Entry
DE = max. size of bytes to read per partial scan
IX = pointer to local memory (allocated in application/popdown workspace, 12 bytes):
(IX + 0,23) : 24bit offset: toInitial fileCRC-32 entryor imageinput (setfrom toresult 0of onprevious inital call), low-byte, high-byte orderpartial CRC-32 scan
(IX + 34,46) : max. bytes to read per partial scanReserved for 24bit file pointer (initialized after first call)
(IX + 57,89) : InitialReserved CRC-32for orsize inputof fromfile resultentry of(initialized previousafter partial CRC-32 scan
OUT, if call successful:
first call)
Fc = 0
(IX + 010,211) : Reserved 24bitfor filemax. pointerbytes updatedto forread nextper partial scan
(IX + 5,8) Subsequent calls:
partial CRC-32 result, low-byte, high-byte order
Fc = 1 BHL = 0 (this is returned automatically after initial call to this method)
AIX = RC_Eof (complete file scanned)
(IX + 5,8) : final CRC-32 result, low-byte, high-byte order
OUT, if call failed:pointer to updated local memory of CRC-32 variables (12 bytes):
OUT:
BHL = 0, always
Fc Fc = 1,0
A = RC_BAD ($04IX + 0,3) - bad argument: partial CRC-32 result, A = RC_xxx (file card related errors)
Registers changed after return:
..BCDEHL/IXIY same
AF....../.... different |
None.
Notes
GN_Crc was implemented in OZ V4.5. It is used by the integrated EazyLink popdown to validate uploaded file content. FlashStore also uses it to display the checksum of a File Entry to be fetched to RAM. GN_Crc will be used more in future OZ developments.
If this system call is used in stand-alone applications, it is necessary to validate which OZ version the application is running on:
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include "fileio.def"low-byte, high-byte order
(IX + 4,6) : 24bit file pointer updated for next partial scan
(IX + 7,9) : Remaining file size updated for next partial scan
(IX + 10,11) : max. bytes to read per partial scan = DE (initial input)
Fc = 1
A = RC_Eof (complete file scanned)
(IX + 0,3) : final CRC-32 result, low-byte, high-byte order;
Fc = 1
A = RC_xxx (System error occurred - file entry corrupt, not found, etc.)
Registers changed on return:
......../IXIY same
AFBCDEHL/.... different |
None.
Notes
GN_Crc was implemented in OZ V4.5. It is used by the integrated EazyLink popdown to validate uploaded file content. FlashStore also uses it to display the checksum of a File Entry to be fetched to RAM. GN_Crc will be used more in future OZ developments.
If this system call is used in stand-alone applications, it is necessary to validate which OZ version the application is running on:
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include "fileio.def"
ld a,FA_PTR
ld ix,ffffh
ld de,0 ; result in DEBC
oz OS_Frm
ld a,44h ; OZ versions are embedded as hexnibbles in C register.
cp c
jr nc, not_ozv45 ; Check for OZ V4.5 failed (44h-45h gives Fc = 1) |
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title | Example for CRC - 32 on memory contents |
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include "crc32.def"
ld a,CRC_MEMA
ld hl,crctext
ld bc,crctext_end - crctext
ld de,0
oz GN_Crc
; CRC–32 returned is 0x414FA339 (DE = 0x414F, BC = 0xA339)
.crctext
defm "The quick brown fox jumps over the lazy dog"
.crctext_end |
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theme | Eclipse |
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title | Example for CRC - 32 on open RAM file using a buffer |
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include "crc32.def"
include "fileio.def"
DEFC FileBufferSize = 1280
DEFVARS $2000 ; "popdown" workspace from 2000H onwards
FileBuffer ds.b FileBufferSize ; buffer for file I/O
ENDDEF
LD A, OP_IN
LD BC,128
LD HL,filename ; pointer to local filename
LD D,H
LD E,L
OZ GN_Opf
JR C,not_available
ld a, CRC_FILE
ld hl,FileBuffer ; use buffer
ld a,FA_PTRbc,FileBufferSize ld
ix,ffffh ld de,0 ; result in DEBC ; Use FFFFFFFFh as initial Crc-32
oz OS_FrmGN_Crc ld a,44h ; get CRC-32 of Open ;file OZ versions are embedded as hexnibbles in C register.(with buffer), returned in DEBC
oz cp GN_Cl c jr nc, not_ozv45 ; Check for OZ V4.5 failed (44h-45h gives; Fcclose =file
1) |
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codeEclipse | title | Example for CRC - 32 on memory contentson open RAM file without buffer (slowest) |
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include "crc32.def"
include "fileio.def"
include "error.def"
ld LD aA,CRC_MEMA OP_IN
ldLD hlBC,crctext128
ld LD bc,crctext_end - crctextHL,filename ld de,0 ; pointer ozto local filename
GN_Crc ; CRC–32LD returned is 0x414FA339D,H
(DE = 0x414F, BC = 0xA339) .crctext LD E,L
OZ defm "The quickGN_Opf brown
fox jumps over the lazy dog" .crctext_end JR C,not_available
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theme | Eclipse |
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title | Example for CRC - 32 on open RAM file using a buffer |
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include "crc32.def"
include "fileio.def"
DEFC FileBufferSize = 1280
DEFVARS $2000 ld a, CRC_PARTFILEBYTE
ld hl,1024 ; read 1024 bytes ;at "popdown"a workspacetime from 2000H onwardsfile
ld bc,$ffff
FileBuffer ds.b FileBufferSize ; buffer for fileld I/O ENDDEF d,b
LDld Ae,c OP_IN LD BC,128 LD ; Use HL,filenameFFFFFFFFh as initial Crc-32
.scan_file
oz ; pointerGN_Crc to local filename LD D,H ; get CRC-32 of LDOpen file E,L(no buffer)
OZjr GN_Opf c,check_eof
JRpush bc
C,not_available push de
ld a, CRC_FILE push hl
ld hl,FileBuffer call do_task
;pop use bufferhl
ldpop de
bc,FileBufferSize pop bc
jr ldscan_file
de,0.check_eof
oz GN_Cl ; Use FFFFFFFFh as initial Crc-32 ; close ozfile
GN_Crc cp Rc_eof
ret ;z get CRC-32 of Open file (with buffer), returned in DEBC oz GN_Cl ; CRC-32 completed, return DEBC to caller
scf ; close file |
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theme | Eclipse |
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title | Example for CRC - 32 on open RAM file without buffer (slowest) |
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include "crc32.def" include "fileio.def" include "error.def" LD A, OP_IN ; other error occurred - LDsignal Fc = BC1,128 A = RC_xxx
LD HL,filename ret |
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title | Example for CRC - 32 on File Entry in File Card |
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include "crc32.def"
include "eprom.def"
ld ;c,2 pointer to local filename LD
D,H ld LD Ede,Lepfilename OZ GN_Opf ; search for filename in filea area of slot JR2
C,not_available
ld a, CRCEP_PARTFILEBYTE
ld hl,1024Find
oz OS_Epr ; read 1024 bytes at a time from file
ld bc,$ffff ret c ld d,b ld e,c ; file area not there
ret nz ; Use FFFFFFFFh as initial Crc-32 .scan_file oz GN_Crc ; file entry not found
ld a, CRC_EPFILE
; get CRC-32 of Open file (no buffer) ld de,0 jr c,check_eof push bc ; Use FFFFFFFFh as initial pushCrc-32
de oz push hl GN_Crc call do_task pop; get hlCRC-32 of File Entry returned in DEBC
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title | Example for CRC - 32 on partial File Entry in File Card |
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include "crc32.def"
popinclude "eprom.def"
de
DEFVARS $2000 pop bc jr scan_file .check_eof ; "popdown" workspace from 2000H onwards
oz GN_Cl FE_CRC32VARS ds.b 12
ENDDEF
ld ; closec,2 file cp Rc_eof
ret zld de,epfilename ; search for filename in ;filea CRC-32 completed, return DEBC to callerarea of slot 2
ld scf a, EP_Find
oz OS_Epr ; other error occurred - signal Fc =
1, A = RC_xxx ret c ret |
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title | Example for CRC - 32 on File Entry in File Card |
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include "crc32.def" include "eprom.def" ld c,2 ; file area not there
ret nz ld de,epfilename ; search for filename in filea; areafile ofentry slotnot 2found
ld ld a, EPCRC_FindPARTEPFILE
ld oz ix, OSFE_EprCRC32VARS ; variable space for partial GN_Crc
ld de,1024 ret c ; Scan max. 1024 bytes per loop iteration, initial Crc-32 is FFFFFFFFh
.crc32_fe_loop
; file area not there oz GN_Crc ret nz ; get partial CRC-32 of File Entry in BHL (or ;BHL file= entry0 notfor foundnext partial block)
ld jr a, CRC_EPFILE c, final_crc32
ld ...
de,0 call do_task
...
; Use FFFFFFFFh as initial Crc-32jr crc32_fe_loop
.final_crc
oz GN_Crc ; CRC-32 is available in (IX+0)
call display_crc32
; get CRC-32 of File Entry returnedret
in DEBC |