Z80-BANKS(5) Bank layout format Z80-BANKS(5) NAME description of file format used by z80-mon for bank layout DESCRIPTION The file compounds of lines each is either a comment line or a bank- or a page description. A comment line starts with a # and may appear anywhere in the file. A line containing a bank description consists of the following 4 entries: access_type bank_id log2_size bank_name. A line containing a page description consists of these 4 entries: either offset or bank_id followed by port_no mask and a non empty list of bank_ids. All bank description lines must preceed the page description lines and must be ordered ascending by their unique bank_id. The following page descrip- tion lines are ordered ascending by their first item which is typically an offset or in the case of a virtuel bank a bank_id. If lines have the same first entry then they must be ordered ascending by their port_id with - re- garded less than any other port_id. And in the case even their second en- tries equals each other, then these lines will be ordered by their mask. A list of bank_ids is an ascending sequence of bank_ids separated only by , (comma), not any whitespace. access_type is the type of the bank. Only the four types + for read/write memory, r for read only memory, w for write only memory and - for a virtuel bank are valid. bank_id is a 2 digit hexadecimal byte value. log2_size gives the size of the bank in bytes as its log2-value. Currently only banks whose log2_size equals 14 (16 kB) or 12 (4 kB) are supported. Due to hardware complexity all banks must have currently the same size! bank_name must either indicate a readable file which contains the machine code for the bank or the special value - (minus) which indicates either undefined storage, typically RAM, or in the case of a virtuel bank no file name. If the corres- sponding file is smaller than the bank size the remaining bytes at the end of the bank will be undefined. If the file size is larger than the bank size only the first bytes in the file will be used. offset is a 4 digit hexadecimal value telling the hardware the start address the bank to be mapped on. Furthermore each offset must be a multiple of 1<<log2_size of the bank size it can be mapped to. port_no is a decimal or hexadecimal number of value < 256 or the character - (minus). In the second case the following mask must be 0. mask is a 2 digit hexadecimal byte value which covers the relevant part of value send to the corresponding port. The port_no together with the given mask must have a unique offset respectively bank_id. Each used bank_id in a page description must be defined in a previous bank description. Summarizing, this file describes how the banks are mapped to memory or other (virtuel) banks. If a byte value is put to a port which has a corresponding page description then a mapping occurs if the bank_id matches the value and-ed with the mask of the port. Therefore page de- scription lines with the same port_no should have different bank_id s for a unique mapping. The default bank_id of a page is the one with the lowest bank_id. This is selected at hardware initialisation and after a bank re- set. SEE ALSO z80-memory(5) Z80-BANKS Version 2.4 18 Apr 2018 Z80-BANKS(5)
NAME | DESCRIPTION | SEE ALSO
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