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CPM OPERATING SYSTEMS/CPM 3.X/CPM 3.0/DEVDIR SOURCE/ASSEMBLE.DOC

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+Assembling CP/M 3
+=================
+
+  The original CP/M 3 build process seems to have been written for a CP/M 3
+computer; it uses the MAC, RMAC, LINK, GENCOM and HEXCOM tools, which are
+not readily available for other platforms in this day and age.
+
+  HEXCOM.C (based on LOAD.C in <ftp://oak.oakland.edu/pub/unix-c/> ) serves
+as a suitable replacement for HEXCOM. The command syntax is:
+
+  HEXCOM comfile <hexfile
+
+  Similarly, to avoid a chicken-and-egg situation (SID is used to build SID),
+HEXPAT.C has been supplied to overlay a COM file with a HEX file.
+
+  The other tools are run under emulation rather than being ported. The
+emulator in question is ZXCC (version 0.3 or later); this can be downloaded
+from <http://www.seasip.demon.co.uk/Cpm/software/linux.html>. It will compile
+under DOS with DJGPP.
+  Note: Earlier versions of ZXCC cannot use LINK on programs bigger than 8k.
+The latest ZXCC is necessary if you want to link the BDOS.
+
+  ZXCC is _not_ a full CP/M emulator. It contains a subset of CP/M sufficient
+to run the build tools above. Its command line syntax is:
+
+  zxcc cpmfile {+}{-}arg1 {+}{-}arg2 ...
+
+  The arguments arg1, arg2 etc. can be:
+
+  filename    Arguments not starting "-" or "+-" are parsed as filenames.
+             This process maps DOS directories to CP/M drives; so you could
+             type ZXCC MAC.CPM G:\ASM\DUMP.ASM and DUMP.ASM would be visible
+             to MAC.
+ +filename    Arguments starting "+" are appended to the preceding argument.
+             See the LINK example below.
+ -text        Text starting "-" is copied in verbatim (not even converted to
+             upper case).
++-text        The text is appended to the previous argument.
+
+  The reason for the "+" options is: Filenames must be passed to ZXCC 
+surrounded by spaces, but ZXCC may need to pass them to the program in the
+middle of a string of text. In this example, ZXCC requires the filename parts
+to be separated by spaces, but they must be passed to LINK as one word:
+
+       LINK BDOS3=CPMBDOSX [OS,$SZ]
+
+becomes
+
+       ZXCC LINK.CPM BDOS3 +-= +CPMBDOSX -[OS,$SZ]
+                           |   |
+              +------------+---+
+              |
+The two + signs are used to remove the spaces either side of the "="; while
+the "-" signs prevent the "=" and the "[OS,$SZ]" from being parsed as 
+filenames.
+