Hi! 17--2006 03:05 [EMAIL PROTECTED] (Michael Devore) wrote to freedos-devel@lists.sourceforge.net:
>> >> May you explain here and/or, better, in comments in source, why >> >> decreasing SP solves issues (and which issues there are)? >> >>>Only plausible explanation: THIS BIOS damages (sometimes ?) the flags; >> >> Do you mean "flags, _saved on the stack above given code_"? >> >> And, if so, then why flags are damaged, but return value, which was lies >> >> on place of flags (relative SP) are not damaged, if you comment out >> >> "pushf"? >>that's all I know. this ugly patch solves the issue. But how you found this?! And what you found? Do you found (with help of debugger?), that "popf" restores not the same value, as "pushf"? And do you try to disasm BIOS INT15 entry to check, what precisely "damages" flags? More details, please! >>looks like sometimes someone damages something on the stack, which >>goes unnoticed most of the time Unless found precise reason, there are no assurance, that your patch fixes (not masks) anything and not damages anything else. >> > Could just be hitting one word on the stack, i.e. [sp] at INT entry. That And? Why return address isn't damaged? Let me ask again: stack: | ret address | +-------------+ | pushf | <- tom thinks, this value damaged +-------------+ | INT15 call | stack after tom's patch: stack: | ret address | <- why this value not damaged? +-------------+ | INT15 call | >> > would match the behavior on either of the two patches. >>right No: in first case stack lesser, in second case it deeper. MD> Plus, I just found out that there exist old compressed DOS programs which MD> avoid the automatic A20 handling of the kernel, Which packer (and/or programs, which packed by this/these packers)? How "avoid"? There is only one (implicit) way for this: call some DOS service before executing decompression. MD> and try to directly use MD> address wrapping, so there's no way to automatically avoid the "packed file MD> is corrupt" termination with high free memory More details, please! MD> In other words, those old MD> programs must use LOADFIX or other workarounds to run. I'm still waiting MD> for some good news to come in. ------------------------------------------------------------------------- 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