[SeaBIOS] Problem with DOS application and 286 DOS Extender application

[Kevin O'Connor]

On Sun, Feb 13, 2011 at 03:06:44PM +0100, Gerhard Wiesinger wrote:
> Hello,
> 
> After some fortune I found out that also Turbo Debugger 286 doesn't
> work under plain DOS 6.22 (without any memory mananger just pressing
> F5) or with some memory mananagers (HIMEM.SYS, EMM386, QEMM386).
> 
> Error message is:
> Error 266 loading D:\DIR\TD286.EXE into extended memory.
> 
> So it looks like that there is a major issue with extended memory.
> Any ideas how to fix or how to find the problem and fix it?
> 
> Version is latest seabios and QEMU from git as of now (own builds).

FYI - I took a quick look at this.  It does not appear to be SeaBIOS
related as SeaBIOS under Bochs works fine.  Qemu fails for me as
reported above.  Kvm (AMD) also fails for me with a slightly different
set of error messages (error "269" instead of "266").

I noticed that under Bochs I get this message as it runs (not sure if
it is meaningful):

00383234030i[CPU0 ] TASK SWITCH: switching to the same TSS !

Under qemu, I see a report of a cpu exception during execution of the
command (again, not sure if it is meaningful).  I grabbed the qemu
execution log around the exception if anyone wishes to take a look at
it.

-Kevin


----------------
IN: 
0x0000000000107694:  pop    %cx
0x0000000000107695:  mov    0x5(%si),%al
0x0000000000107698:  and    $0xfd,%al
0x000000000010769a:  mov    %al,0x5(%si)
0x000000000010769d:  xor    %ax,%ax
0x000000000010769f:  mov    %ax,-0x8(%bp)
0x00000000001076a2:  mov    -0x2(%bp),%ax
0x00000000001076a5:  mov    %ax,-0x6(%bp)
0x00000000001076a8:  ltr    %ax
0x00000000001076ab:  push   %cx
0x00000000001076ac:  mov    %ax,%cx
0x00000000001076ae:  call   0x105530

EAX=00000158 EBX=00008000 ECX=00000158 EDX=000041b0
ESI=00000148 EDI=00000278 EBP=00000589 ESP=0000057d
EIP=00002cf0 EFL=00000046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0028 0001b940 00002f1f 00009300 DPL=0 DS16 [-WA]
CS =0020 00102840 0000ffff 00009a00 DPL=0 CS16 [-R-]
SS =0150 0010b5e0 000005ce 00009300 DPL=0 DS16 [-WA]
DS =0008 0001b440 000003ff 00009300 DPL=0 DS16 [-WA]
FS =0010 0001b940 0000ffff 00009300 DPL=0 DS16 [-WA]
GS =0010 0001b940 0000ffff 00009300 DPL=0 DS16 [-WA]
LDT=0000 00000000 00000000 00008200 DPL=0 LDT
TR =0158 0010bbc0 000005ce 00008100 DPL=0 TSS16-avl
GDT=     0001b440 000003ff
IDT=     00100010 000007ff
CR0=00000013 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
DR6=00000000ffff0ff0 DR7=0000000000000400
CCS=000000a4 CCD=00000000 CCO=LOGICW  
EFER=0000000000000000
EAX=00000158 EBX=00008000 ECX=00000158 EDX=000041b0
ESI=00000158 EDI=00000278 EBP=00000589 ESP=0000057f
EIP=00004e71 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0028 0001b940 00002f1f 00009300 DPL=0 DS16 [-WA]
CS =0020 00102840 0000ffff 00009a00 DPL=0 CS16 [-R-]
SS =0150 0010b5e0 000005ce 00009300 DPL=0 DS16 [-WA]
DS =0008 0001b440 000003ff 00009300 DPL=0 DS16 [-WA]
FS =0010 0001b940 0000ffff 00009300 DPL=0 DS16 [-WA]
GS =0010 0001b940 0000ffff 00009300 DPL=0 DS16 [-WA]
LDT=0000 00000000 00000000 00008200 DPL=0 LDT
TR =0158 0010bbc0 000005ce 00008100 DPL=0 TSS16-avl
GDT=     0001b440 000003ff
IDT=     00100010 000007ff
CR0=00000013 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
DR6=00000000ffff0ff0 DR7=0000000000000400
CCS=000000ac CCD=00000158 CCO=SHLW    
EFER=0000000000000000
----------------
IN: 
0x00000000001076b1:  pop    %cx
0x00000000001076b2:  mov    0x5(%si),%al
0x00000000001076b5:  and    $0xfd,%al
0x00000000001076b7:  mov    %al,0x5(%si)
0x00000000001076ba:  ljmp   *-0x8(%bp)

check_exception old: 0xffffffff new 0xa
     0: v=0a e=0160 i=0 cpl=0 IP=0160:0000000000000000 pc=0000000000000000 SP=0168:00000000ffff05c4 EAX=00000000ffff0000
EAX=ffff0000 EBX=ffff0000 ECX=ffff0000 EDX=ffff0000
ESI=ffff0000 EDI=ffff0000 EBP=ffff0000 ESP=ffff05c4
EIP=00000000 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 00000000 00000000
CS =0160 00000000 00000000 00000000
SS =0168 00000000 00000000 00000000
DS =0170 00000000 00000000 00000000
FS =0000 00000000 00000000 00000000
GS =0000 00000000 00000000 00000000
LDT=0168 0010c1a0 00007fff 00008200 DPL=0 LDT
TR =0158 0010bbc0 000005ce 00008100 DPL=0 TSS16-avl
GDT=     0001b440 000003ff
IDT=     00100010 000007ff
CR0=0000001b CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
DR6=00000000ffff0ff0 DR7=0000000000000400
CCS=00000000 CCD=00000081 CCO=LOGICB  
EFER=0000000000000000
EAX=ffff0000 EBX=ffff0000 ECX=ffff0000 EDX=ffff0000
ESI=ffff0000 EDI=ffff0000 EBP=ffff0000 ESP=ffff05bc
EIP=00003ae8 EFL=00000086 [--S--P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 00000000 00000000
CS =0020 00102840 0000ffff 00009a00 DPL=0 CS16 [-R-]
SS =0168 00000000 00000000 00000000
DS =0170 00000000 00000000 00000000
FS =0000 00000000 00000000 00000000
GS =0000 00000000 00000000 00000000
LDT=0168 0010c1a0 00007fff 00008200 DPL=0 LDT
TR =0158 0010bbc0 000005ce 00008100 DPL=0 TSS16-avl
GDT=     0001b440 000003ff
IDT=     00100010 000007ff
CR0=0000001b CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
DR6=00000000ffff0ff0 DR7=0000000000000400
CCS=00000000 CCD=00000081 CCO=LOGICB  
EFER=0000000000000000
----------------
IN: 
0x0000000000106328:  push   %ds
0x0000000000106329:  call   0x107626

EAX=ffff0000 EBX=ffff0000 ECX=ffff0000 EDX=ffff0000
ESI=ffff0000 EDI=ffff0000 EBP=ffff0000 ESP=ffff05b8
EIP=00004de6 EFL=00000086 [--S--P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 00000000 00000000
CS =0020 00102840 0000ffff 00009a00 DPL=0 CS16 [-R-]
SS =0168 00000000 00000000 00000000
DS =0170 00000000 00000000 00000000
...