diff options
Diffstat (limited to 'drivers/gpu/drm/amd/display/dc/calcs/custom_float.c')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/calcs/custom_float.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/calcs/custom_float.c b/drivers/gpu/drm/amd/display/dc/calcs/custom_float.c new file mode 100644 index 000000000000..7243c37f569e --- /dev/null +++ b/drivers/gpu/drm/amd/display/dc/calcs/custom_float.c @@ -0,0 +1,197 @@ +/* + * Copyright 2017 Advanced Micro Devices, Inc. + * + * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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. + * + * Authors: AMD + * + */ +#include "dm_services.h" +#include "custom_float.h" + + +static bool build_custom_float( + struct fixed31_32 value, + const struct custom_float_format *format, + bool *negative, + uint32_t *mantissa, + uint32_t *exponenta) +{ + uint32_t exp_offset = (1 << (format->exponenta_bits - 1)) - 1; + + const struct fixed31_32 mantissa_constant_plus_max_fraction = + dal_fixed31_32_from_fraction( + (1LL << (format->mantissa_bits + 1)) - 1, + 1LL << format->mantissa_bits); + + struct fixed31_32 mantiss; + + if (dal_fixed31_32_eq( + value, + dal_fixed31_32_zero)) { + *negative = false; + *mantissa = 0; + *exponenta = 0; + return true; + } + + if (dal_fixed31_32_lt( + value, + dal_fixed31_32_zero)) { + *negative = format->sign; + value = dal_fixed31_32_neg(value); + } else { + *negative = false; + } + + if (dal_fixed31_32_lt( + value, + dal_fixed31_32_one)) { + uint32_t i = 1; + + do { + value = dal_fixed31_32_shl(value, 1); + ++i; + } while (dal_fixed31_32_lt( + value, + dal_fixed31_32_one)); + + --i; + + if (exp_offset <= i) { + *mantissa = 0; + *exponenta = 0; + return true; + } + + *exponenta = exp_offset - i; + } else if (dal_fixed31_32_le( + mantissa_constant_plus_max_fraction, + value)) { + uint32_t i = 1; + + do { + value = dal_fixed31_32_shr(value, 1); + ++i; + } while (dal_fixed31_32_lt( + mantissa_constant_plus_max_fraction, + value)); + + *exponenta = exp_offset + i - 1; + } else { + *exponenta = exp_offset; + } + + mantiss = dal_fixed31_32_sub( + value, + dal_fixed31_32_one); + + if (dal_fixed31_32_lt( + mantiss, + dal_fixed31_32_zero) || + dal_fixed31_32_lt( + dal_fixed31_32_one, + mantiss)) + mantiss = dal_fixed31_32_zero; + else + mantiss = dal_fixed31_32_shl( + mantiss, + format->mantissa_bits); + + *mantissa = dal_fixed31_32_floor(mantiss); + + return true; +} + +static bool setup_custom_float( + const struct custom_float_format *format, + bool negative, + uint32_t mantissa, + uint32_t exponenta, + uint32_t *result) +{ + uint32_t i = 0; + uint32_t j = 0; + + uint32_t value = 0; + + /* verification code: + * once calculation is ok we can remove it + */ + + const uint32_t mantissa_mask = + (1 << (format->mantissa_bits + 1)) - 1; + + const uint32_t exponenta_mask = + (1 << (format->exponenta_bits + 1)) - 1; + + if (mantissa & ~mantissa_mask) { + BREAK_TO_DEBUGGER(); + mantissa = mantissa_mask; + } + + if (exponenta & ~exponenta_mask) { + BREAK_TO_DEBUGGER(); + exponenta = exponenta_mask; + } + + /* end of verification code */ + + while (i < format->mantissa_bits) { + uint32_t mask = 1 << i; + + if (mantissa & mask) + value |= mask; + + ++i; + } + + while (j < format->exponenta_bits) { + uint32_t mask = 1 << j; + + if (exponenta & mask) + value |= mask << i; + + ++j; + } + + if (negative && format->sign) + value |= 1 << (i + j); + + *result = value; + + return true; +} + +bool convert_to_custom_float_format( + struct fixed31_32 value, + const struct custom_float_format *format, + uint32_t *result) +{ + uint32_t mantissa; + uint32_t exponenta; + bool negative; + + return build_custom_float( + value, format, &negative, &mantissa, &exponenta) && + setup_custom_float( + format, negative, mantissa, exponenta, result); +} + + |