Hello Eric, > In summary, I would say it might be nice to have a command > line option "lock a20 to on" for emm386, for example after > FreeDOS 1.0 is done. You should do some benchmarks on a slow > 386sx PC in the meantime ;-). By the way, it also might be > nice to have an option "turn a20 on now and then lock it" > for HIMEM as well. I think Tom once supported such an option. yes. but I removed this later, for the simple reason that there exist EXEPACK'ed programs (to avoid discussion)
> PS: Normally, only DOS disables the a20, and only when a > program starts. It then enables the a20 again as soon as > the HMA is needed again. So it is not switched often anyway. > If DOS -knew- that you locked the a20 to on, DOS could skip > the "check if a20 is on" each time before it jumps to HMA. > But there is no interface for that in the DOS kernel. it's not worth the trouble. a) each DOS interrupt costs a few thousand instructions; doing 10 more doesn't hurt b) there's usually VERY little time spend in the kernel; you'd probably not notice if it would be in interpreted basic Tom ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
