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Date: Sun, 4 Nov 2018 15:09:32 +0000 (GMT)
Sender: "Maciej W. Rozycki" <macro@linux-mips.org>
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Subject: Re: [Qemu-devel] [PATCH 1/2] target/mips: Fix decoding mechanism of
 R5900 MFLO1, MFHI1, MTLO1 and MTHI1
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To: Fredrik Noring <noring@nocrew.org>
Cc: Richard Henderson <richard.henderson@linaro.org>, =?UTF-8?Q?Philippe_Mathieu-Daud=C3=A9?= <f4bug@amsat.org>, Aleksandar Markovic <amarkovic@wavecomp.com>, Aurelien Jarno <aurelien@aurel32.net>, =?UTF-8?Q?J=C3=BCrgen_Urban?= <JuergenUrban@gmx.de>, qemu-devel@nongnu.org

On Sun, 4 Nov 2018, Fredrik Noring wrote:

> It appears the correct function is tcg_gen_mov_tl because the TX79 manual
> says
> 
> 	MFHI:  GPR[rd]63..0 <- HI63..0
> 	MFLO:  GPR[rd]63..0 <- LO63..0
> 	MTHI:  HI63..0 <- GPR[rs]63..0
> 	MTLO:  LO63..0 <- GPR[rs]63..0
> 	MFHI1: GPR[rd]63..0 <- HI127..64
> 	MFLO1: GPR[rd]63..0 <- LO127..64
> 	MTHI1: HI127..64 <- GPR[rs]63..0
> 	MTLO1: LO127..64 <- GPR[rs]63..0
> 
> so the GPR is copied to/from in full in all cases. This is slightly
> different to how acc = 1 is handled in gen_HILO.

 However `gen_HILO' looks wrong to me as it'll truncate the values of 
$acc3-$acc1 with the 64-bit DSP ASE.

  Maciej