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      1 /*
      2  * Copyright  2014 Intel Corporation
      3  *
      4  * Permission is hereby granted, free of charge, to any person obtaining a
      5  * copy of this software and associated documentation files (the "Software"),
      6  * to deal in the Software without restriction, including without limitation
      7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      8  * and/or sell copies of the Software, and to permit persons to whom the
      9  * Software is furnished to do so, subject to the following conditions:
     10  *
     11  * The above copyright notice and this permission notice (including the next
     12  * paragraph) shall be included in all copies or substantial portions of the
     13  * Software.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     21  * IN THE SOFTWARE.
     22  */
     23 
     24 #include <gtest/gtest.h>
     25 #include <math.h>
     26 #include "brw_reg.h"
     27 
     28 class vf_float_conversion_test : public ::testing::Test {
     29    virtual void SetUp();
     30 
     31 public:
     32    float vf_to_float[128];
     33 };
     34 
     35 void vf_float_conversion_test::SetUp() {
     36    /* 0 is special cased. */
     37    vf_to_float[0] = 0.0;
     38 
     39    for (int vf = 1; vf < 128; vf++) {
     40       int ebits = (vf >> 4) & 0x7;
     41       int mbits = vf & 0xf;
     42 
     43       float x = 1.0f + mbits / 16.0f;
     44       int exp = ebits - 3;
     45 
     46       vf_to_float[vf] = ldexpf(x, exp);
     47    }
     48 }
     49 
     50 union fu {
     51    float f;
     52    unsigned u;
     53 };
     54 
     55 static unsigned
     56 f2u(float f)
     57 {
     58    union fu fu;
     59    fu.f = f;
     60    return fu.u;
     61 }
     62 
     63 TEST_F(vf_float_conversion_test, test_vf_to_float)
     64 {
     65    for (int vf = 0; vf < 256; vf++) {
     66       float expected = vf_to_float[vf % 128];
     67       if (vf > 127)
     68          expected = -expected;
     69 
     70       EXPECT_EQ(f2u(expected), f2u(brw_vf_to_float(vf)));
     71    }
     72 }
     73 
     74 TEST_F(vf_float_conversion_test, test_float_to_vf)
     75 {
     76    for (int vf = 0; vf < 256; vf++) {
     77       float f = vf_to_float[vf % 128];
     78       if (vf > 127)
     79          f = -f;
     80 
     81       EXPECT_EQ(vf, brw_float_to_vf(f));
     82    }
     83 }
     84 
     85 TEST_F(vf_float_conversion_test, test_special_case_0)
     86 {
     87    /* 0.0f are special cased to the VFs that would otherwise correspond
     88     * to 0.125f. Make sure we can't convert these values to VF.
     89     */
     90    EXPECT_EQ(brw_float_to_vf(+0.125f), -1);
     91    EXPECT_EQ(brw_float_to_vf(-0.125f), -1);
     92 
     93    EXPECT_EQ(f2u(brw_vf_to_float(brw_float_to_vf(+0.0f))), f2u(+0.0f));
     94    EXPECT_EQ(f2u(brw_vf_to_float(brw_float_to_vf(-0.0f))), f2u(-0.0f));
     95 }
     96 
     97 TEST_F(vf_float_conversion_test, test_nonrepresentable_float_input)
     98 {
     99    EXPECT_EQ(brw_float_to_vf(+32.0f), -1);
    100    EXPECT_EQ(brw_float_to_vf(-32.0f), -1);
    101 
    102    EXPECT_EQ(brw_float_to_vf(+16.5f), -1);
    103    EXPECT_EQ(brw_float_to_vf(-16.5f), -1);
    104 
    105    EXPECT_EQ(brw_float_to_vf(+8.25f), -1);
    106    EXPECT_EQ(brw_float_to_vf(-8.25f), -1);
    107 
    108    EXPECT_EQ(brw_float_to_vf(+4.125f), -1);
    109    EXPECT_EQ(brw_float_to_vf(-4.125f), -1);
    110 }
    111