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+qemu crashes on unaligned extended disk reads
+
+When performing a BIOS extended disk read (INT 13H, AH=0x42), if the offset of the buffer destination in the DAP (disk address packet) is not dword-aligned (i.e. a multiple of 4), SeaBIOS attempts to execute code at non-mapped address 0xb4f53, causing QEMU to crash. I imagine it's a bug in the BIOS code, but it does cause QEMU to crash.
+
+QEMU version: 1.4.0 (Debian 1.4.0+dfsg-1expubuntu4) (from Ubuntu repository)
+SeaBIOS version: 1.7.2-20130119_170942-roseapple
+command line: qemu-system-x86_64 -m 64 -hda hda.img -monitor stdio
+CPU: Intel Core i7 CPU M620 on a Dell Latitude E6410
+OS: Ubuntu, GNU/Linux 3.8.0-25-generic, 64-bit
+
+On Tue, Jun 18, 2013 at 09:23:31PM -0000, Andrew McGowen wrote:
+> When performing a BIOS extended disk read (INT 13H, AH=0x42), if the
+> offset of the buffer destination in the DAP (disk address packet) is not
+> dword-aligned (i.e. a multiple of 4), SeaBIOS attempts to execute code
+> at non-mapped address 0xb4f53, causing QEMU to crash. I imagine it's a
+> bug in the BIOS code, but it does cause QEMU to crash.
+
+Can you post details on the "crash"?  What is the error message?
+
+Stefan
+
+
+...well this is embarrassing - it was an issue with my code not saving/restoring registers on the stack properly.
+
+Marking this ticket as "Invalid" according to comment #2.
+