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Created page with 'AMSDOS uses two memory blocks. The first is always at BE40h..BE7Fh (on the 464 this region was used as Stack). The second is allocated from User RAM, typically located at A700h..…'
AMSDOS uses two memory blocks. The first is always at BE40h..BE7Fh (on the 464 this region was used as Stack). The second is allocated from User RAM, typically located at A700h..ABFFh (unless other expansion ROMs with higher ROM bank number have already allocated RAM at that locations).
== AMSDOS RAM 1 (always at BE40h..BE7Fh) ==
BE40 2 Pointer to Disk Parameter Header for Drive A (A910h) (CPM:AE58h)
BE42 2 Pointer to Disk Parameter Block for Drive A (A890h) (CPM:ADD8h)
BE44 2 Delay for Motor Spin-up in 1/50 seconds (0032h)
BE46 2 Delay for Motor Spin-down in 1/50 seconds (00FAh)
BE48 1 Delay for Formatting in whatever units (AFh)
BE49 1 Delay for whatever in milliseconds (0Fh)
BE4A 1 Delay for Track-Settle in milliseconds (0Ch)
BE4B 1 Number of bytes received in Result Phase
BE4C 7 Response from FDC in Result Phase
BE53 1 Drive HS/US
BE54 1 Track
BE55 1 Record
BE56 1 Drive HS/US
BE57 1 Track
BE58 1 Sector
BE59 1 Number of Records per Track? or (Blockmask+1)?
BE5A 1 Drive HS/US
BE5B 1 Track
BE5C 1 Record
BE5D 1 ?
BE5E 1 Flag Read/Write Sector
BE5F 1 Flag On/Off Motor
BE60 2 Pointer to 128-byte Directory Record I/O Buffer (A930h) (CPM:0080h)
BE62 2 Pointer to 512-byte Sector I/O Buffer (A9B0h) (CPM:AEF8h)
BE64 2 Stack...Temporary...? (BFxxh)
BE66 1 Number of retries (10h)
BE67 6 Ticker Block (Chain,Count,Reload)
BE6D 7 Event Block (Chain,Count,Class,Proc,Bank)
BE74 1 Desired Track or Sector Number
BE75 1 FDC Command Number
BE76 2 Pointer to 512-byte Sector I/O Buffer (A9B0h) (CPM:AEF8h)
BE78 1 Flag Enable/Disable Error Messages
BE79 1 Reserved
BE7A 1 Reserved, CPC+: 00h=No Disc (464+), FFh=Disc (6128+)
BE7B 2 Reserved
BE7D 2 Pointer to Memory Pool (A700h) (CPM:N/A)
BE7F 1 Hook (C9h)
== AMSDOS RAM 2 (usually at A6FCh..ABFFh) ==
A6FC 4 AMSDOS RSX Block (Next block, AMSDOS ROM bank) (0000h,0007h)
A700 1 Default Drive (00h or 01h)
A701 1 Default User (00h and up)
A702 1 Active Drive (00h or 01h)
A703 2 Pointer to DPH for Active Drive (A910h or A920h)
A705 1 Flag if OPEN on Default Drive
A706 2 Stackpointer
A708 36 Extended File Control Block for OPENIN
A72C 36 Extended File Control Block for OPENOUT
A750 74 File Header for OPENIN
A79A 74 File Header for OPENOUT
A7E4 128 Temporary Record & Filename Buffer
A864 39 Original CAS_Function Vectors (13 x 3 bytes)
A88B 3 FAR Address for RST4 in patched CAS_vectors
A88E 2 ?
A890 64 Extended Disk Parameter Block Drive A
A8D0 64 Extended Disk Parameter Block Drive B
A910 16 Disk Parameter Header Drive A
A920 16 Disk Parameter Header Drive B
A930 128 Record Buffer for Directory Records
A9B0 512 Sector Buffer
ABB0 80 Reserved
== Extended File Control Block (FCB) for OPENIN/OPENOUT ==
00h 1 Drive Number (00h=A, 01h=B, FFh=Not Open)
01h 1 User Number
02h 8 Filename (padded with 20h)
0Ah 3 Extension (padded with 20h)
0Dh 1 Extent Number (00h=First directory entry of file)
0Eh 2 Zero
10h 1 Number of Records in current Extent
11h 16 Block Numbers for current Extent
21h 3 Number of previously accessed Records
== File Header for OPENIN/OPENOUT ==
00h 1 Access Mode (1=CHAR, 2=DIRECT)
01h 2 Pointer to 2K work buffer
03h 2 Pointer to current CHAR in 2K work buffer
05h 16 User Number and Filename (padded with 00h)
15h 1 Block Number (whatever, can be zero)
16h 1 Last Block (whatever, can be zero)
17h 1 File Type (00h=Basic, 01h=EncryptedBasic, 02h=Binary)
18h 2 Data Length (whatever, can be zero)
1Ah 2 Load Address in memory
1Ch 1 First Block FFh
1Dh 2 Filesize (excluding the 80h-byte header)
1Fh 2 Entrypoint (for executable binary files)
21h 36 Unused (free for user?) (parts are used for OPENOUT)
45h 3 24bit Filepos in CHARs, or 16bit Filesize if non-ASCII file
48h 2 Checksum accross [05h..47h]
== Extended Disk Parameter Block (DPB,CSA,ALT) for Drive A/B ==
00h 2 SPT Records per Track (CPM/Data=36, IBM=32)
02h 1 BSH Block Shift (3) (records per block = 1 SHL N)
03h 1 BLM Block Mask (7) (records per block minus 1)
04h 1 EXM Extend Mask (0)
05h 2 DSM Max Block Number (CPM=170, Data=179, IBM=155)
07h 2 DRM Max Dir Entries-1 (63)
09h 2 AL Directory Allocation Table (11000000b,00000000b = Block 0,1)
0Bh 2 CKS Check Area Size (Size of the "CSA" field) (0010h)
0Dh 2 OFF Track Offset (Size of Bootstrap) (CPM=2, Data=0, IBM=1)
0Fh 1 FSC First Sector on Track (CPM=41h, Data=C1h, IBM=01h)
10h 1 PST Physical Sectors per Track (CPM/Data=9, IBM=8)
11h 1 GPS GAP3 for Sector Read/Write (2Ah)
12h 1 GPT GAP3 for Track Formatting (52h)
13h 1 FLB Fillbyte for Track Formatting (E5h)
14h 1 BPS Bytes per Sector (2=512) (80h SHL N, Shift amount or so?)
15h 1 RPS Records per Sector (4)
16h 1 Current Track
17h 1 Recalibrate Track 0 Flag
18h 1 Flag Login on any access ? (re-detect CPM/Data format?)
19h 16 CSA Checksums (directory record chksums, for sensing disk-changes)
29h 23 ALT Block Allocation Table (23x8bit = 184bit) (only 180bit used)
== Disk Paramter Header (DPH) for Drive A/B ==
00h 2 XLT Skew Factor Translation (physical-to-logical sector) (not used)
02h 2 TRACK Current Track (misused as DIRNUM by AMSDOS)
04h 2 SECTOR Current Sector
06h 2 DIRNUM Current Directory Number
08h 2 DIRBUF Pointer to Directory Buffer (A930h)
0Ah 2 DPB Pointer to DPB (A890h/A8D0h for Drive A/B) Drive Param Block
0Ch 2 CSV Pointer to CSA (A8A9h/A8E9h for Drive A/B) Checksums
0Eh 2 ALV Pointer to ALT (A8B9h/A8F9h for Drive A/B) Allocation Table
== AMSDOS RAM 1 (always at BE40h..BE7Fh) ==
BE40 2 Pointer to Disk Parameter Header for Drive A (A910h) (CPM:AE58h)
BE42 2 Pointer to Disk Parameter Block for Drive A (A890h) (CPM:ADD8h)
BE44 2 Delay for Motor Spin-up in 1/50 seconds (0032h)
BE46 2 Delay for Motor Spin-down in 1/50 seconds (00FAh)
BE48 1 Delay for Formatting in whatever units (AFh)
BE49 1 Delay for whatever in milliseconds (0Fh)
BE4A 1 Delay for Track-Settle in milliseconds (0Ch)
BE4B 1 Number of bytes received in Result Phase
BE4C 7 Response from FDC in Result Phase
BE53 1 Drive HS/US
BE54 1 Track
BE55 1 Record
BE56 1 Drive HS/US
BE57 1 Track
BE58 1 Sector
BE59 1 Number of Records per Track? or (Blockmask+1)?
BE5A 1 Drive HS/US
BE5B 1 Track
BE5C 1 Record
BE5D 1 ?
BE5E 1 Flag Read/Write Sector
BE5F 1 Flag On/Off Motor
BE60 2 Pointer to 128-byte Directory Record I/O Buffer (A930h) (CPM:0080h)
BE62 2 Pointer to 512-byte Sector I/O Buffer (A9B0h) (CPM:AEF8h)
BE64 2 Stack...Temporary...? (BFxxh)
BE66 1 Number of retries (10h)
BE67 6 Ticker Block (Chain,Count,Reload)
BE6D 7 Event Block (Chain,Count,Class,Proc,Bank)
BE74 1 Desired Track or Sector Number
BE75 1 FDC Command Number
BE76 2 Pointer to 512-byte Sector I/O Buffer (A9B0h) (CPM:AEF8h)
BE78 1 Flag Enable/Disable Error Messages
BE79 1 Reserved
BE7A 1 Reserved, CPC+: 00h=No Disc (464+), FFh=Disc (6128+)
BE7B 2 Reserved
BE7D 2 Pointer to Memory Pool (A700h) (CPM:N/A)
BE7F 1 Hook (C9h)
== AMSDOS RAM 2 (usually at A6FCh..ABFFh) ==
A6FC 4 AMSDOS RSX Block (Next block, AMSDOS ROM bank) (0000h,0007h)
A700 1 Default Drive (00h or 01h)
A701 1 Default User (00h and up)
A702 1 Active Drive (00h or 01h)
A703 2 Pointer to DPH for Active Drive (A910h or A920h)
A705 1 Flag if OPEN on Default Drive
A706 2 Stackpointer
A708 36 Extended File Control Block for OPENIN
A72C 36 Extended File Control Block for OPENOUT
A750 74 File Header for OPENIN
A79A 74 File Header for OPENOUT
A7E4 128 Temporary Record & Filename Buffer
A864 39 Original CAS_Function Vectors (13 x 3 bytes)
A88B 3 FAR Address for RST4 in patched CAS_vectors
A88E 2 ?
A890 64 Extended Disk Parameter Block Drive A
A8D0 64 Extended Disk Parameter Block Drive B
A910 16 Disk Parameter Header Drive A
A920 16 Disk Parameter Header Drive B
A930 128 Record Buffer for Directory Records
A9B0 512 Sector Buffer
ABB0 80 Reserved
== Extended File Control Block (FCB) for OPENIN/OPENOUT ==
00h 1 Drive Number (00h=A, 01h=B, FFh=Not Open)
01h 1 User Number
02h 8 Filename (padded with 20h)
0Ah 3 Extension (padded with 20h)
0Dh 1 Extent Number (00h=First directory entry of file)
0Eh 2 Zero
10h 1 Number of Records in current Extent
11h 16 Block Numbers for current Extent
21h 3 Number of previously accessed Records
== File Header for OPENIN/OPENOUT ==
00h 1 Access Mode (1=CHAR, 2=DIRECT)
01h 2 Pointer to 2K work buffer
03h 2 Pointer to current CHAR in 2K work buffer
05h 16 User Number and Filename (padded with 00h)
15h 1 Block Number (whatever, can be zero)
16h 1 Last Block (whatever, can be zero)
17h 1 File Type (00h=Basic, 01h=EncryptedBasic, 02h=Binary)
18h 2 Data Length (whatever, can be zero)
1Ah 2 Load Address in memory
1Ch 1 First Block FFh
1Dh 2 Filesize (excluding the 80h-byte header)
1Fh 2 Entrypoint (for executable binary files)
21h 36 Unused (free for user?) (parts are used for OPENOUT)
45h 3 24bit Filepos in CHARs, or 16bit Filesize if non-ASCII file
48h 2 Checksum accross [05h..47h]
== Extended Disk Parameter Block (DPB,CSA,ALT) for Drive A/B ==
00h 2 SPT Records per Track (CPM/Data=36, IBM=32)
02h 1 BSH Block Shift (3) (records per block = 1 SHL N)
03h 1 BLM Block Mask (7) (records per block minus 1)
04h 1 EXM Extend Mask (0)
05h 2 DSM Max Block Number (CPM=170, Data=179, IBM=155)
07h 2 DRM Max Dir Entries-1 (63)
09h 2 AL Directory Allocation Table (11000000b,00000000b = Block 0,1)
0Bh 2 CKS Check Area Size (Size of the "CSA" field) (0010h)
0Dh 2 OFF Track Offset (Size of Bootstrap) (CPM=2, Data=0, IBM=1)
0Fh 1 FSC First Sector on Track (CPM=41h, Data=C1h, IBM=01h)
10h 1 PST Physical Sectors per Track (CPM/Data=9, IBM=8)
11h 1 GPS GAP3 for Sector Read/Write (2Ah)
12h 1 GPT GAP3 for Track Formatting (52h)
13h 1 FLB Fillbyte for Track Formatting (E5h)
14h 1 BPS Bytes per Sector (2=512) (80h SHL N, Shift amount or so?)
15h 1 RPS Records per Sector (4)
16h 1 Current Track
17h 1 Recalibrate Track 0 Flag
18h 1 Flag Login on any access ? (re-detect CPM/Data format?)
19h 16 CSA Checksums (directory record chksums, for sensing disk-changes)
29h 23 ALT Block Allocation Table (23x8bit = 184bit) (only 180bit used)
== Disk Paramter Header (DPH) for Drive A/B ==
00h 2 XLT Skew Factor Translation (physical-to-logical sector) (not used)
02h 2 TRACK Current Track (misused as DIRNUM by AMSDOS)
04h 2 SECTOR Current Sector
06h 2 DIRNUM Current Directory Number
08h 2 DIRBUF Pointer to Directory Buffer (A930h)
0Ah 2 DPB Pointer to DPB (A890h/A8D0h for Drive A/B) Drive Param Block
0Ch 2 CSV Pointer to CSA (A8A9h/A8E9h for Drive A/B) Checksums
0Eh 2 ALV Pointer to ALT (A8B9h/A8F9h for Drive A/B) Allocation Table
