Re: [Valgrind-users] Information on adding unknown instructions due to "illegal opcde"?

[John R. <jr...@bi...>]

> Is there any information on adding support for unsupported instructions?

At this point, with >99% of instructions already recognized,
then you should reason by analogy.  Use a debugger such as gdb
to trace the execution under valgrind of a similar instruction,
then modify and extend to handle the unimplemented instruction.
For a 'rotate' instruction, use the corresponding right-shift.

Hints:
Assemble the two-line program
	_start: .globl _start
		.word <the-bits-for-your-instruction>
using
	gcc -nostartfiles  -nodefaultlibs  -nostdlib foo.S
to get an executable file with a .text that has 4==.p_memsz.
Then run memcheck on that executable.

Run "valgrind --help-debug" and look carefully at "Vex options
for all Valgrind tools", particularly --trace-flags.

Read "Debugging Valgrind with GDB" in README_DEVELOPERS.

The code is in VEX/priv/guest_arm*