[PATCH 1/5] powerpc/lib/sstep: Add cmpb instruction emulation

Segher Boessenkool segher at kernel.crashing.org
Thu Jul 13 16:43:53 AEST 2017


On Thu, Jul 13, 2017 at 01:51:30PM +1000, Andrew Donnellan wrote:
> On 13/07/17 13:25, Matt Brown wrote:
> >@@ -1049,6 +1066,13 @@ int analyse_instr(struct instruction_op *op, struct 
> >pt_regs *regs,
> > 			do_cmp_unsigned(regs, val, val2, rd >> 2);
> > 			goto instr_done;
> >
> >+		case 19173952: /* cmpb */
> 
> This looks wrong and should never trigger, given that the switch 
> statement is comparing against ((instr >> 1) & 0x3ff).
> 
> How did you get this value?

The correct number is 508, and 19173952 = 37744*508.  How to get
37744 is a mystery though :-)


Segher


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