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// SPDX-License-Identifier: MIT
//
// Copyright 2024 Advanced Micro Devices, Inc.
#include "spl_debug.h"
#include "spl_custom_float.h"
static bool spl_build_custom_float(struct spl_fixed31_32 value,
const struct spl_custom_float_format *format,
bool *negative,
uint32_t *mantissa,
uint32_t *exponenta)
{
uint32_t exp_offset = (1 << (format->exponenta_bits - 1)) - 1;
const struct spl_fixed31_32 mantissa_constant_plus_max_fraction =
spl_fixpt_from_fraction((1LL << (format->mantissa_bits + 1)) - 1,
1LL << format->mantissa_bits);
struct spl_fixed31_32 mantiss;
if (spl_fixpt_eq(value, spl_fixpt_zero)) {
*negative = false;
*mantissa = 0;
*exponenta = 0;
return true;
}
if (spl_fixpt_lt(value, spl_fixpt_zero)) {
*negative = format->sign;
value = spl_fixpt_neg(value);
} else {
*negative = false;
}
if (spl_fixpt_lt(value, spl_fixpt_one)) {
uint32_t i = 1;
do {
value = spl_fixpt_shl(value, 1);
++i;
} while (spl_fixpt_lt(value, spl_fixpt_one));
--i;
if (exp_offset <= i) {
*mantissa = 0;
*exponenta = 0;
return true;
}
*exponenta = exp_offset - i;
} else if (spl_fixpt_le(mantissa_constant_plus_max_fraction, value)) {
uint32_t i = 1;
do {
value = spl_fixpt_shr(value, 1);
++i;
} while (spl_fixpt_lt(mantissa_constant_plus_max_fraction, value));
*exponenta = exp_offset + i - 1;
} else {
*exponenta = exp_offset;
}
mantiss = spl_fixpt_sub(value, spl_fixpt_one);
if (spl_fixpt_lt(mantiss, spl_fixpt_zero) ||
spl_fixpt_lt(spl_fixpt_one, mantiss))
mantiss = spl_fixpt_zero;
else
mantiss = spl_fixpt_shl(mantiss, format->mantissa_bits);
*mantissa = spl_fixpt_floor(mantiss);
return true;
}
static bool spl_setup_custom_float(const struct spl_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) {
SPL_BREAK_TO_DEBUGGER();
mantissa = mantissa_mask;
}
if (exponenta & ~exponenta_mask) {
SPL_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 spl_convert_to_custom_float_format(struct spl_fixed31_32 value,
const struct spl_custom_float_format *format,
uint32_t *result)
{
uint32_t mantissa;
uint32_t exponenta;
bool negative;
return spl_build_custom_float(value, format, &negative, &mantissa, &exponenta) &&
spl_setup_custom_float(format,
negative,
mantissa,
exponenta,
result);
}
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