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Diffstat (limited to 'qemu/roms/seabios/docs/Debugging.md')
| -rw-r--r-- | qemu/roms/seabios/docs/Debugging.md | 27 |
1 files changed, 16 insertions, 11 deletions
diff --git a/qemu/roms/seabios/docs/Debugging.md b/qemu/roms/seabios/docs/Debugging.md index 03567de4d..7ab5d02d8 100644 --- a/qemu/roms/seabios/docs/Debugging.md +++ b/qemu/roms/seabios/docs/Debugging.md @@ -55,8 +55,10 @@ rate. The tool can also timestamp the messages from the QEMU debug port. To use with QEMU run the following: -`mkfifo qemudebugpipe`\ -`qemu -chardev pipe,path=qemudebugpipe,id=seabios -device isa-debugcon,iobase=0x402,chardev=seabios ...` +``` +mkfifo qemudebugpipe +qemu -chardev pipe,path=qemudebugpipe,id=seabios -device isa-debugcon,iobase=0x402,chardev=seabios ... +``` and then in another session: @@ -84,20 +86,23 @@ bios 16bit code) or out/rom.o (to debug bios 32bit code). For example: `gdb out/rom16.o` -Once in gdb, use the command "target remote localhost:1234" to have +Once in gdb, use the command `target remote localhost:1234` to have gdb connect to QEMU. See the QEMU documentation for more information on using gdb and QEMU in this mode. -When debugging 16bit code, also run the following commands in gdb: +When debugging 16bit code it is necessary to load the 16bit symbols +twice in order for gdb to properly handle break points. To do this, +run the following command `objcopy --adjust-vma 0xf0000 out/rom16.o +rom16offset.o` and then run the following in gdb: -`set architecture i8086`\ -`add-symbol-file out/rom16.o 0xf0000` +``` +set architecture i8086 +add-symbol-file rom16offset.o 0 +``` -The second command loads the 16bit symbols a second time at an offset -of 0xf0000, which helps gdb set and catch breakpoints correctly. - -To debug a VGA BIOS image, run "gdb out/vgarom.o" add use the gdb -command "add-symbol-file out/vgarom.o 0xc0000" to load the 16bit VGA +To debug a VGA BIOS image, run `gdb out/vgarom.o`, create a +vgaromoffset.o file with offset 0xc0000, add use the gdb +command `add-symbol-file out/vgaromoffset.o 0` to load the 16bit VGA BIOS symbols twice. If debugging the 32bit SeaBIOS initialization code with gdb, note that |