Recreating byte exact source for RC702 adapted SYSGEN.COM
For backward compatibility the RC702 system had multiple densities on the 8" floppy disks. This in turn required the SYSGEN utility to be modified to handle this.
Michael Ringgård mentions on http://www.jbox.dk/rc702/cpm.shtm that this was one of the sources he did not find when working on his RC702 emulator.
At init time I checked in SYSGEN.ASM from http://www.cpm.z80.de/source.html http://www.cpm.z80.de/download/cpm2-plm.zip as SYSGEN.ORG, and used IDA37FW to investigate SYSGEN.COM to get a rough disassembly of the code.
Use
MAC SYSGEN
LOAD SYSGEN
under e.g. RunCMD to create a new SYSGEN.COM. See http://www.cpm.z80.de/manuals/mac.pdf for documentation.
If zmac is available on the host system, use
zmac -8 --dri SYSGEN.ASM
to create zout/SYSGEN.cim which is binary identical to SYSGEN.COM generated above. See http://48k.ca/zmac.html for details.
Use
grep -q '04EF SIGNON' SYSGEN.SYM && dhex RCSYSGEN.COM SYSGEN.COM
to view the binary differences. The grep ensures that the byte alignment is correct.
Before committing to git, remove CP/M ^Z EOF characters so git will recognize the file as ascii:
perl -i -pe 's/\032//g' SYSGEN.SYM
- ERROR MESSAGES When errors occur within the assembly language program, they are listed as single character flags in the leftmost position of the source listing. The line in error is also echoed at the console so that the source listing need not be examined to determine if errors are present. The single character error codes are:
- B Balance error: macro doesn't terminate properly, or conditional assembly operation is ill-formed.
- C Comma error: expression was encountered, but not delimited properly from the next item by a comma.
- D Data error: element in a data statement (DB or DW) cannot be placed in the specified data area.
- E Expression error: expression is ill-formed and cannot be computed at assembly time.
- I Invalid character error: a non graphic character has been found in the line (not a carriage return, line feed, tab, or end of file); re-edit the file, delete the line with the I error, and retype the line.
- L Label error: label cannot appear in this context (may be a duplicate label).
- M Macro overflow error: internal macro expansion table overflow; may be due to too many nested invocations or infinite recursion.
- N Not implemented error: features which will appear in future MAC versions (e.g., relocation) are recognized, but flagged in this version.
- O Overflow error: expression is too complicated (i.e., too many pending operators), string is too long, or too many successive substitutions of a formal parameter by its actual value in a macro expansion. This error will also occur if the number of LOCAL labels exceeds 9999.
- P Phase error: label does not have the same value on two subsequent passes through the program, or the order of macro definition differs between two successive passes; may be due to MACLIB which follows a mainline macro (if so, move the MACLIB to the top of the program).
- R Register error: the value specified as a register is not compatible with the operation code.
- S Syntax error: the fields of this statement are ill-formed and cannot be processed properly; may be due to invalid characters or delimiters which are out of place.
- U Undefined Symbol: a label operand in this statement has not been defined elsewhere in the program.
- V Value error: operand encountered in an expression is improperly formed; may be due to delimiter out of place or non-numeric operand.
/ravn 2023-04-28