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Date: Thu, 13 Jul 2017 02:47:32 -0500
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Matt Brown <matthew.brown.dev@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, anton@samba.org
Subject: Re: [PATCH 5/5] powerpc/lib/sstep: Add isel instruction emulation
Message-ID: <20170713074732.GD13471@gate.crashing.org>
References: <20170713032548.451-1-matthew.brown.dev@gmail.com>
 <20170713032548.451-5-matthew.brown.dev@gmail.com>
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On Thu, Jul 13, 2017 at 01:25:48PM +1000, Matt Brown wrote:
> +		case 585:	/* isel */

The secondary opcode for isel is only 5 bits, not 10 like most other
insns have.

> +			mb = (instr >> 6) & 0x1f; /* bc */
> +			val = (regs->ccr >> (mb + 32)) & 1;

regs->ccr >> (31 - mb)  ?

> +
> +			if (val)
> +				regs->gpr[rd] = regs->gpr[ra];

You need to treat ra=0 separately (as 0, not reg 0).

> +			else
> +				regs->gpr[rd] = regs->gpr[rb];
> +			goto logical_done;


Segher