Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 5564 | serge | 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 | #include "brw_reg.h" |
||
| 24 | |||
| 25 | union fu { |
||
| 26 | float f; |
||
| 27 | unsigned u; |
||
| 28 | struct { |
||
| 29 | unsigned mantissa:23; |
||
| 30 | unsigned exponent:8; |
||
| 31 | unsigned sign:1; |
||
| 32 | } s; |
||
| 33 | }; |
||
| 34 | |||
| 35 | int |
||
| 36 | brw_float_to_vf(float f) |
||
| 37 | { |
||
| 38 | union fu fu = { .f = f }; |
||
| 39 | |||
| 40 | /* ±0.0f is special cased. */ |
||
| 41 | if (f == 0.0f) |
||
| 42 | return fu.s.sign << 7; |
||
| 43 | |||
| 44 | unsigned mantissa = fu.s.mantissa >> (23 - 4); |
||
| 45 | unsigned exponent = fu.s.exponent - (127 - 3); |
||
| 46 | unsigned vf = (fu.s.sign << 7) | (exponent << 4) | mantissa; |
||
| 47 | |||
| 48 | /* 0.125 would have had the same representation as 0.0, so reject it. */ |
||
| 49 | if ((vf & 0x7f) == 0) |
||
| 50 | return -1; |
||
| 51 | |||
| 52 | /* Make sure the mantissa fits in 4-bits and the exponent in 3-bits. */ |
||
| 53 | if (fu.u & 0x7ffff || exponent > 7) |
||
| 54 | return -1; |
||
| 55 | |||
| 56 | return vf; |
||
| 57 | } |
||
| 58 | |||
| 59 | float |
||
| 60 | brw_vf_to_float(unsigned char vf) |
||
| 61 | { |
||
| 62 | union fu fu; |
||
| 63 | |||
| 64 | /* ±0.0f is special cased. */ |
||
| 65 | if (vf == 0x00 || vf == 0x80) { |
||
| 66 | fu.u = vf << 24; |
||
| 67 | return fu.f; |
||
| 68 | } |
||
| 69 | |||
| 70 | fu.s.sign = vf >> 7; |
||
| 71 | fu.s.exponent = ((vf & 0x70) >> 4) + (127 - 3); |
||
| 72 | fu.s.mantissa = (vf & 0xf) << (23 - 4); |
||
| 73 | |||
| 74 | return fu.f; |
||
| 75 | } |