Re: failed 'ljmp' in linear addressing mode

2006-12-01 Thread Jun Sun
On Wed, Nov 22, 2006 at 03:41:11PM -0800, Jun Sun wrote: > > I am plowing along as I am learning about the in'n'outs about i386. I am > totally stuck on this one. I would appreciate any help. > > As you can see, the function turns off paging mode (of course it > runs from identically mapped pag

Re: failed 'ljmp' in linear addressing mode

2006-11-30 Thread Phillip Susi
linux-os (Dick Johnson) wrote: Get a copy of the Intel 486 Microprocessor Reference Manual or read it on- line. There is no way that you can make a call like that. You would need to call through a task-gate or otherwise set the code-segment and the instruction pointer at the same instant. First,

Re: failed 'ljmp' in linear addressing mode

2006-11-29 Thread Jun Sun
On Tue, Nov 28, 2006 at 05:40:56PM -0800, Jun Sun wrote: > > Can you elaborate more why this last ljmp will fail? I thought at this point > the paging is turned off, and 0x1000- would simply mean a physical > address - which is a valid physical address in RAM, btw. > I finally got it workin

Re: failed 'ljmp' in linear addressing mode

2006-11-28 Thread Jun Sun
On Tue, Nov 28, 2006 at 06:49:17PM -0500, linux-os (Dick Johnson) wrote: > > On Tue, 28 Nov 2006, Jun Sun wrote: > > > On Tue, Nov 28, 2006 at 08:46:44AM -0500, linux-os (Dick Johnson) wrote: > >> > >> On Mon, 27 Nov 2006, Jun Sun wrote: > >> > >>> > >>> On Mon, Nov 27, 2006 at 08:58:57AM -0500,

Re: failed 'ljmp' in linear addressing mode

2006-11-28 Thread linux-os \(Dick Johnson\)
On Tue, 28 Nov 2006, Jun Sun wrote: > On Tue, Nov 28, 2006 at 08:46:44AM -0500, linux-os (Dick Johnson) wrote: >> >> On Mon, 27 Nov 2006, Jun Sun wrote: >> >>> >>> On Mon, Nov 27, 2006 at 08:58:57AM -0500, linux-os (Dick Johnson) wrote: I think it probably resets the instant that you tu

Re: failed 'ljmp' in linear addressing mode

2006-11-28 Thread Jun Sun
On Tue, Nov 28, 2006 at 08:46:44AM -0500, linux-os (Dick Johnson) wrote: > > On Mon, 27 Nov 2006, Jun Sun wrote: > > > > > On Mon, Nov 27, 2006 at 08:58:57AM -0500, linux-os (Dick Johnson) wrote: > >> > >> I think it probably resets the instant that you turn off paging. To > >> turn off paging, y

Re: failed 'ljmp' in linear addressing mode

2006-11-28 Thread linux-os \(Dick Johnson\)
On Mon, 27 Nov 2006, Jun Sun wrote: > > On Mon, Nov 27, 2006 at 08:58:57AM -0500, linux-os (Dick Johnson) wrote: >> >> I think it probably resets the instant that you turn off paging. To >> turn off paging, you need to copy some code (properly linked) to an >> area where there is a 1:1 mapping be

Re: failed 'ljmp' in linear addressing mode

2006-11-27 Thread Jun Sun
On Mon, Nov 27, 2006 at 08:58:57AM -0500, linux-os (Dick Johnson) wrote: > > I think it probably resets the instant that you turn off paging. To > turn off paging, you need to copy some code (properly linked) to an > area where there is a 1:1 mapping between virtual and physical addresses. > A sa

Re: failed 'ljmp' in linear addressing mode

2006-11-27 Thread linux-os \(Dick Johnson\)
On Wed, 22 Nov 2006, Jun Sun wrote: > > I am plowing along as I am learning about the in'n'outs about i386. I am > totally stuck on this one. I would appreciate any help. > > As you can see, the function turns off paging mode (of course it > runs from identically mapped page) and tries to jump