Displaying 2 results from an estimated 2 matches for "constraintcheckmethod".
2013 Apr 30
3
[LLVMdev] A simpler method to reject undefined encodings
...fieldFromInstruction(Insn, 16, 4);
Q = fieldFromInstruction(Insn, 6, 1);
if (Q == 1 && ((Vd & 1) || (Vm & 1) || (Vn & 1)))
return MCDisassembler::Fail;
return MCDIsassembler::Success;
}
Then I'd like to use this in the td file with something along the lines of
ConstraintCheckMethod = "CheckNEONConstraint"
in the superclass of NEON instructions.
I envision this as the very last step in deciding whether an encoding is
valid or not. In my example the tablegen generated decoder would "decode"
the invalid encoding and create a MCInst but, because this final t...
2013 May 01
0
[LLVMdev] A simpler method to reject undefined encodings
Hi Mihail,
> static DecodeStatus CheckNEONConstraint(const MCInst &Inst, unsigned Insn)
[...]
> ConstraintCheckMethod = "CheckNEONConstraint"
In general I like the idea of an instruction-validation method. I
think it could also potentially solve the SoftFail/UNPREDICTABLE
issues that are looming (and partially resolved for decoding at
present).
However, I think that to cope with the other issues the sc...