Date: Fri, 19 Apr 2019 16:00:05 -0700 From: Mark Millard <marklmi@yahoo.com> To: FreeBSD PowerPC ML <freebsd-ppc@freebsd.org>, Justin Hibbits <chmeeedalf@gmail.com> Subject: Re: head -r346144 vs. "or 27,27,27" use (via cpu_spinwait) Message-ID: <D7464FDC-A6C4-47C6-BEC6-9C7A6206E5B7@yahoo.com> In-Reply-To: <B2B3221D-71F9-48ED-9CA3-FE3650F1C377@yahoo.com> References: <B2B3221D-71F9-48ED-9CA3-FE3650F1C377@yahoo.com>
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On 2019-Apr-19, at 15:20, Mark Millard <marklmi at yahoo.com> wrote:
> There still seems to be:
>=20
> /usr/src/sys/powerpc/include/cpu.h:#define cpu_spinwait() =
__asm __volatile("or 27,27,27") /* yield */
>=20
> used in powerpc_ipi_handler and ofw_rendezvous_dispatch
> and mpc85xx_jog_set_int .
>=20
> (It is not clear to me what the status of "or 27,27,27" is
> on older processors, like in PowerMacs. 27 was not
> documented before PowerISA 2.06 . (I looked in 2.03, 2.04,
> 2.05, 2.06B V2, 2.07, and 3.0B.)
I forgot to mention, PowerISA 3.0B no longer lists information
about any of:
or 27,27,27
or 29,29,29
or 30,30,30
2.07 and 3.0B do list information for:
or 26,26,26
No prior ones do.
=3D=3D=3D
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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