There is one thint that I am aware of, and I use in my OpenWatcom programs: In a 586 execution will be faster if the instructions are rearanged, but still using only 386 instructions...
Alain Em 03-05-2013 03:48, Eric Auer escreveu: > > Hoi Louis, > > please explain the hack / patch: Is the only thing that > you changed that the kernel is compiled for those CPUs? > Are there actually any differences between them? I can > imagine that OpenWatcom makes 186 and 286 the same and > everything above 386 the same. Unless the kernel would > contain heavy mathematical processing for which it is > obvious that above-386 optimizes better ;-) You could > tell the compiler to produce Assembly output (instead > of binary) and compare the text. Or you could use some > debug, disassembler (ndisasm?) or hex editor to compare > before you UPX things, but of course that is more work. > > Thanks for comparing :-) Maybe this is more a topic for > the kernel list. Note that if "a few" bytes are really > only 10 or so, all this is probably more an "academic" > exercise. Things get more exciting once you can save at > least a cluster of disk space or a paragraph of RAM :-) > > Regards, Eric > >> I hacked the 2041 kernel batch and make files included on the FD 1.1 iso to >> allow the kernel to be built by OpenWatcom as 8086, 186, 286, 386, 486, >> 586, or 686. The resulting 686 kernel boots fine in VirtualBox 4.2.12 in >> OSX 10.8.3 on my 2012 Mac Book Air 13" 4GB. The resulting kernel is a few >> bytes smaller compressed by upx than kernel installed by the FD 1.1 iso. >> I'm going to continue testing. No source changes were made. Not sure how >> the changes affect the nasm built files. > > > > > ------------------------------------------------------------------------------ > Get 100% visibility into Java/.NET code with AppDynamics Lite > It's a free troubleshooting tool designed for production > Get down to code-level detail for bottlenecks, with<2% overhead. > Download for free and get started troubleshooting in minutes. > http://p.sf.net/sfu/appdyn_d2d_ap2 > _______________________________________________ > Freedos-user mailing list > Freedos-user@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freedos-user > ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite It's a free troubleshooting tool designed for production Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap2 _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
