freebsd-dev/lib/libc/powerpcspe/gen/flt_rounds.c
Justin Hibbits dc9b124d66 Create a new MACHINE_ARCH for Freescale PowerPC e500v2
Summary:
The Freescale e500v2 PowerPC core does not use a standard FPU.
Instead, it uses a Signal Processing Engine (SPE)--a DSP-style vector processor
unit, which doubles as a FPU.  The PowerPC SPE ABI is incompatible with the
stock powerpc ABI, so a new MACHINE_ARCH was created to deal with this.
Additionaly, the SPE opcodes overlap with Altivec, so these are mutually
exclusive.  Taking advantage of this fact, a new file, powerpc/booke/spe.c, was
created with the same function set as in powerpc/powerpc/altivec.c, so it
becomes effectively a drop-in replacement.  setjmp/longjmp were modified to save
the upper 32-bits of the now-64-bit GPRs (upper 32-bits are only accessible by
the SPE).

Note: This does _not_ support the SPE in the e500v1, as the e500v1 SPE does not
support double-precision floating point.

Also, without a new MACHINE_ARCH it would be impossible to provide binary
packages which utilize the SPE.

Additionally, no work has been done to support ports, work is needed for this.
This also means no newer gcc can yet be used.  However, gcc's powerpc support
has been refactored which would make adding a powerpcspe-freebsd target very
easy.

Test Plan:
This was lightly tested on a RouterBoard RB800 and an AmigaOne A1222
(P1022-based) board, compiled against the new ABI.  Base system utilities
(/bin/sh, /bin/ls, etc) still function appropriately, the system is able to boot
multiuser.

Reviewed By:	bdrewery, imp
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D5683
2016-10-22 01:57:15 +00:00

58 lines
2.2 KiB
C

/* $NetBSD: flt_rounds.c,v 1.4.10.3 2002/03/22 20:41:53 nathanw Exp $ */
/*
* Copyright (c) 2016 Justin Hibbits
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Mark Brinicombe
* for the NetBSD Project.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <machine/float.h>
#include <machine/spr.h>
#ifndef _SOFT_FLOAT
static const int map[] = {
1, /* round to nearest */
0, /* round to zero */
2, /* round to positive infinity */
3 /* round to negative infinity */
};
int
__flt_rounds()
{
uint32_t fpscr;
__asm__ __volatile("mfspr %0, %1" : "=r"(fpscr) : "K"(SPR_SPEFSCR));
return map[(fpscr & 0x03)];
}
#endif