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fpu.cc
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fpu.cc
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/* Copyright (C) 2015 Goswin von Brederlow <[email protected]>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* FPU support for the Raspberry Pi
*/
#include <stdint.h>
#include "fpu.h"
namespace FPU {
// Enable Advanced SIMD & Vector Floating Point Calculations (NEON MPE)
void init(void) {
uint32_t reg;
// read Access Control Register
asm volatile("mrc p15,0,%0,c1,c0,2" : "=r" (reg));
// Enable Single & Double Precision
reg |= 0x300000 + 0xC00000;
// write Access Control Register
asm volatile("mcr p15,0,%0,c1,c0,2" :: "r" (reg));
// enable VFP
asm volatile("vmsr fpexc,%0" :: "r" (0x40000000));
}
}