Matches in DBpedia 2014 for { <http://dbpedia.org/resource/Zero_page_(CP/M)> ?p ?o. }
Showing items 1 to 16 of
16
with 100 items per page.
- M) abstract "The Zero Page (or Base Page) is a data structure used in CP/M systems for programs to communicate with the operating system. In 8-bit CP/M versions it is located in the first 256 bytes of memory, hence its name.The equivalent structure in MS-DOS is the Program Segment Prefix.In 8-bit CP/M, it has the following structure:Offset Size Contents--------------------------------------------------------------------00-02 Code Exit program (jumps to the BIOS, and is also used to find BIOS entry points).03 Byte I/O byte, an optional feature allowing device reassignment in CP/M 2.04 Byte Current command processor drive (low 4 bits) and user number (high 4 bits).05-07 Code Jump to CP/M BDOS entry - main system call entry point. This is also the address of the first byte of memory not usable by the program.08-3A Code 8080 restart/interrupt vectors.3B-4F Bytes Reserved50 Byte The drive from which the program was loaded (CP/M 3)51-52 Word Address of the password for the first FCB (CP/M 3)53 Byte Length of the password for the first FCB (CP/M 3)54-55 Word Address of the password for the second FCB (CP/M 3)56 Byte Length of the password for the second FCB (CP/M 3)57-5B Bytes Reserved5C-6B Default FCB 16C-7F Default FCB 2 (overwritten if FCB 1 is opened)80 Byte Number of characters in command tail.81-FF Bytes Command tail (everything after the program name).In CP/M-86, the structure is:Offset Size Contents--------------------------------------------------------------------00-02 Bytes Length of code group in bytes03-04 Word Segment address of code group05 Byte 8080 model flag - set if program only has one segment06-08 Bytes Length of data group in bytes09-0A Word Segment address of data group0B Byte Reserved0C-11 Descriptor for extra group - same format as for data12-17 Descriptor for stack group18-1D Descriptor for X1 group1E-23 Descriptor for X2 group24-29 Descriptor for X3 group2A-2F Descriptor for X4 group30-4F Bytes Reserved50 Byte The drive from which the program was loaded (CP/M 3)51-52 Word Address of the password for the first FCB (CP/M 3)53 Byte Length of the password for the first FCB (CP/M 3)54-55 Word Address of the password for the second FCB (CP/M 3)56 Byte Length of the password for the second FCB (CP/M 3)57-5B Bytes Reserved5C-6B Default FCB 16C-7F Default FCB 2 (overwritten if FCB 1 is opened)80 Byte Number of characters in command tail.81-FF Bytes Command tail (everything after the program name).".
- M) wikiPageExternalLink CPM-86_System_Guide.pdf.
- M) wikiPageExternalLink c247i.
- M) wikiPageExternalLink drilib.html.
- M) wikiPageExternalLink cpm3-pgr.pdf.
- M) wikiPageID "2203335".
- M) wikiPageRevisionID "578393972".
- M) hasPhotoCollection M).
- M) subject M_technology.
- M) comment "The Zero Page (or Base Page) is a data structure used in CP/M systems for programs to communicate with the operating system.".
- M) label "Zero page (CP/M)".
- M) sameAs m.06vnpk.
- M) sameAs Q8069603.
- M) sameAs Q8069603.
- M) wasDerivedFrom M)?oldid=578393972.
- M) isPrimaryTopicOf M).