http://d.puremagic.com/issues/show_bug.cgi?id=5517
--- Comment #4 from Don <clugd...@yahoo.com.au> 2011-03-05 18:28:56 PST --- (In reply to comment #3) > (In reply to comment #2) > > Some further detail: 0xF4, the HLT opcode, is a privileged instruction; it > > doesn't actually get executed. Instead, a Privileged Instruction hardware > > exception is raised. I would expect Linux to turn this into SIGILL. So I > > would > > expect an exit code of 132, if nothing is done to process it. There is no > > way > > it should give a SEGV. > > > > If I was going off what I recall, I would have said that when a program > receives the hlt instruction; it just stops executing instructions until there > is an interrupt (in other words it just floats off in an undefined space). That's what it does in ring 0 (ie, inside the kernel). But outside the kernel, it's a privileged instruction, which generates a hardware 'illegal instruction' interrupt. > But I've looked it up, and HLT invokes SIGSEGV signal afterall... Wow. Then Linux is just wrong. It should definitely be SIGILL. There's no memory access violation. > > On Windows, druntime checks the offending instruction, and if it is HLT, it > > is > > identified as a runtime assert(0). > > So on Windows, the runtime has a bespoke signal handler? Everything you'd call a signal on Linux, is just a system exception on Windows. D's exception handling uses the exact same mechanism. On all platforms, main is surrounded by a catch(...) which displays error messages from any uncaught exceptions. On Windows, this includes hardware faults as well as D-generated exceptions. The impression I get from the little I know of Unix signal handling, it seems to be one of the few things that Unix got horribly wrong. Windows structured exception handling is brilliant (albeit almost completely undocumented!) I am extremely impressed with it. For example, there's no restrictions on what you can do inside an exception handler. So there's probably more challenges for the *nix implementation of a lot of this stuff. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
