Hi Kevin, Long time ago I read about OS/2 calling 16-bit protected mode BIOS, but the documentation didn't specified if this was constrained to the separate protected mode BIOS included by PS/2 systems or the real mode BIOS included by the same PS/2 systems and the whole rest of PC computers.
Regards, Natalia Portillo El 14/06/2012, a las 04:13, Kevin O'Connor escribió: > Hi, > > I am trying to determine if there are legacy applications or operating > systems that invoke standard BIOS real-mode interrupt handlers while > in 16bit protected mode. (The legacy real-mode entry points - like > "int 0x13" - not the declared 16bit protected mode entry points > defined by the PnP and APM specs.) > > I am considering changes to SeaBIOS that would make 16bit protected > mode callers much less likely to work. (Specifically, enhancing > SeaBIOS to use memory in the e-segment which is unlikely to be mapped > in protected mode.) > > Most documents I've seen state that calling the real-mode entry points > in protected mode will not work. Though, I am aware that the PCI BIOS > spec specifically requires this support for calls to "int 0x1a > ah=0xb1". > > The advantage of making these changes is that it will allow SeaBIOS to > use notably less stack space and therefore be more compatible with old > applications that call the BIOS with very little stack space. For > example, these changes enable DOS 1.0 to boot and run under SeaBIOS. > > What would really help is pointers to applications and/or program > images that use 16bit protected mode calls to real-mode entry points. > Specifications or documents detailing valid or invalid uses would also > be helpful. > > For those that are willing to run tests, one can compare the standard > SeaBIOS v1.7.0 image (for KVM/QEMU) at: > > http://git.seabios.org/downloads/get/bios.bin-1.7.0.gz > > to a test image with the new code at: > > http://git.seabios.org/downloads/get/bios.bin-test-20120613.gz > > Thanks, > -Kevin >
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