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Date: Thu, 4 Dec 2014 09:40:24 -0800 From: David Daney <ddaney@...iumnetworks.com> To: "Maciej W. Rozycki" <macro@...ux-mips.org> CC: Leonid Yegoshin <Leonid.Yegoshin@...tec.com>, David Daney <ddaney.cavm@...il.com>, <linux-mips@...ux-mips.org>, Ralf Baechle <ralf@...ux-mips.org>, <Zubair.Kakakhel@...tec.com>, <geert+renesas@...der.be>, <peterz@...radead.org>, <paul.gortmaker@...driver.com>, <chenhc@...ote.com>, <cl@...ux.com>, Ingo Molnar <mingo@...nel.org>, <richard@....at>, <zajec5@...il.com>, <james.hogan@...tec.com>, <keescook@...omium.org>, <tj@...nel.org>, <alex@...x-smith.me.uk>, <pbonzini@...hat.com>, <blogic@...nwrt.org>, <paul.burton@...tec.com>, <qais.yousef@...tec.com>, <linux-kernel@...r.kernel.org>, <markos.chandras@...tec.com>, <dengcheng.zhu@...tec.com>, <manuel.lauss@...il.com>, <lars.persson@...s.com>, David Daney <david.daney@...ium.com> Subject: Re: [PATCH 2/3] MIPS: Add full ISA emulator. On 12/04/2014 03:49 AM, Maciej W. Rozycki wrote: > On Wed, 3 Dec 2014, David Daney wrote: > >>> but it doesn't support customized instructions, >> >> GCC will never put these in the delay slot of a FPU branch, so it is not >> needed. >> >>> multiple ASEs, >> >> Same as above. But any instructions that are deemed necessary can easily be >> added. > > GAS will happily schedule any instruction into a branch delay slot as > long as the instruction is not architecturally forbidden there (e.g. > ERET), there is no data dependency with the branch that would affect the > result produced and the instruction is not an explicit exception trap > operation (BREAK, SYSCALL, TEQ, etc.). For some reason, unknown to me all > MT ASE instructions are disallowed too. Anything else -- free to go in! > > Of course instructions can be scheduled into branch delay slots manually > too, in handcoded assembly, and that has to continue working. > It is not difficult to also emulate the trapping instructions. In order to move forward, I will implement the trapping instructions in my emulator for the next patch. Thanks, David Daney -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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