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diff --git a/dos/README b/dos/README new file mode 100644 index 00000000..649c58c4 --- /dev/null +++ b/dos/README @@ -0,0 +1,113 @@ + +XZ Utils on DOS +=============== + +Introduction + + This document explains how to build XZ Utils for DOS using DJGPP. + The resulting binaries should run at least on various DOS versions + and under Windows 95/98/98SE/ME, which cannot run the Windows version + of XZ Utils. + + This is currently experimental and has got very little testing. + + +Getting and Installing DJGPP + + You may use <http://www.delorie.com/djgpp/zip-picker.html> to help + deciding what to download, but as of writing (2009-02-13) that may + not be the most convenient way taking into account what components + are actually required to build XZ Utils. However, using the + zip-picker can still be worth doing to get nice short summary of + installation instructions (they can be found from readme.1st too). + + For more manual method, first select a mirror from + <http://www.delorie.com/djgpp/getting.html>. You need + the following files: + + unzip32.exe + beta/v2/djdev204.zip + v2gnu/bnu219b.zip + v2gnu/gcc432b.zip + v2gnu/mak3791b.zip + v2gnu/sed415b.zip + v2misc/csdpmi5b.zip + + If newer versions are available, probably you should try them first. + Note that djdev203.zip is too old to build XZ Utils; you need at + least djdev204.zip. Also note that you want csdpmi5b.zip even if you + run under Windows or DOSEMU, because the XZ Utils Makefile will embed + cwsdstub.exe to the resulting binaries. + + See the instructions in readme.1st found from djdev204.zip. Here's + a short summary, but you should still read readme.1st. + + C:\> mkdir DJGPP + C:\> cd DJGPP + C:\DJGPP> c:\download\unzip32 c:\download\djdev204.zip + C:\DJGPP> c:\download\unzip32 c:\download\bnu219b.zip + C:\DJGPP> c:\download\unzip32 c:\download\gcc432b.zip + C:\DJGPP> c:\download\unzip32 c:\download\mak3791b.zip + C:\DJGPP> c:\download\unzip32 c:\download\sed415b.zip + C:\DJGPP> c:\download\unzip32 c:\download\csdpmi5b.zip + + C:\DJGPP> set PATH=C:\DJGPP\BIN;%PATH% + C:\DJGPP> set DJGPP=C:\DJGPP\DJGPP.ENV + + You may want to add the last two lines into AUTOEXEC.BAT or have, + for example, DJGPP.BAT which you can run before using DJGPP. + + Make sure you use completely upper case path in the DJGPP environment + variable. This is not required by DJGPP, but the XZ Utils Makefile is + a bit stupid and expects that everything in DJGPP environment variable + is uppercase. + + +Building + + Just run "make" in this directory (the directory containing this + README). You should get liblzma.a, xz.exe, xzdec.exe, and + lzmadec.exe. Of these, probably xz.exe is the only interesting one. + + Note: You need to have an environment that supports long filenames. + Once you have built XZ Utils, the resulting binaries can be run + without long filename support. + + +Additional Make Flags and Targets + + You may want to try some additional optimizations, which may or + may not make the code faster (and may or may not hit possible + compiler bugs more easily): + + make CFLAGS="-O3 -fomit-frame-pointer -funroll-loops" + + If you want to enable assertions (the assert() macro), use DEBUG=1. + You may want to disable optimizations too if you plan to actually + debug the code. Never use DEBUG=1 for production builds! + + make DEBUG=1 CFLAGS="-g -O0" + + +Bugs + + "make clean" may remove src/xz/hardware.c when it tries to remove + src/xz/hardware-fixed.c. This is probably a bug somewhere in the + DOS environment I use. Maybe it tries truncated 8.3 name first and + since that gives a name of an existing file, it doesn't look for + long filename. + + "xz -fc /dev/tty" hangs at least in DOSEMU and cannot be interrupted + by pressing C-c. Maybe xz should never accept non-regular files on + DOS even when --force is used. + + Using different memory usage limit for encoding and decoding doesn't + make sense under pure DOS. Maybe it is still OK when running under + Windows. + + The progress indicator of "xz -v" doesn't get updated when running + under Dosbox, but it works in DOSEMU. I currently (2009-02-13) don't + know if it works in other environments. + + Report bugs to <lasse.collin@tukaani.org> (in English or Finnish). + |