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/*
* Copyright © 2014 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "brw_reg.h"
union fu {
float f;
unsigned u;
struct {
unsigned mantissa:23;
unsigned exponent:8;
unsigned sign:1;
} s;
};
int
brw_float_to_vf(float f)
{
union fu fu = { .f = f };
/* ±0.0f is special cased. */
if (f == 0.0f)
return fu.s.sign << 7;
unsigned mantissa = fu.s.mantissa >> (23 - 4);
unsigned exponent = fu.s.exponent - (127 - 3);
unsigned vf = (fu.s.sign << 7) | (exponent << 4) | mantissa;
/* 0.125 would have had the same representation as 0.0, so reject it. */
if ((vf & 0x7f) == 0)
return -1;
/* Make sure the mantissa fits in 4-bits and the exponent in 3-bits. */
if (fu.u & 0x7ffff || exponent > 7)
return -1;
return vf;
}
float
brw_vf_to_float(unsigned char vf)
{
union fu fu;
/* ±0.0f is special cased. */
if (vf == 0x00 || vf == 0x80) {
fu.u = vf << 24;
return fu.f;
}
fu.s.sign = vf >> 7;
fu.s.exponent = ((vf & 0x70) >> 4) + (127 - 3);
fu.s.mantissa = (vf & 0xf) << (23 - 4);
return fu.f;
}
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