DBT-RISE-TGC/src/vm/fp_functions.cpp

749 lines
25 KiB
C++

////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2017, MINRES Technologies GmbH
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Contributors:
// eyck@minres.com - initial API and implementation
////////////////////////////////////////////////////////////////////////////////
#include "fp_functions.h"
#include <array>
extern "C" {
#include "internals.h"
#include "specialize.h"
#include <softfloat.h>
}
#include <limits>
using this_t = uint8_t*;
// this does not inlcude any reserved rm or the DYN rm, as DYN rm should be taken care of in the vm_impl
const std::array<uint8_t, 7> rmm_map = {softfloat_round_near_even /*RNE*/,
softfloat_round_minMag /*RTZ*/,
softfloat_round_min /*RDN*/,
softfloat_round_max /*RUP?*/,
softfloat_round_near_maxMag /*RMM*/,
0 /*reserved*/,
softfloat_round_odd /*ROD*/};
const uint32_t quiet_nan32 = 0x7fC00000;
extern "C" {
uint32_t fget_flags() { return softfloat_exceptionFlags & 0x1f; }
uint16_t fsqrt_h(uint16_t v1, uint8_t mode) {
float16_t v1f{v1};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float16_t r = f16_sqrt(v1f);
return r.v;
}
uint16_t fclass_h(uint16_t v1) {
float16_t a{v1};
union ui16_f16 uA;
uint_fast16_t uiA;
uA.f = a;
uiA = uA.ui;
bool infOrNaN = expF16UI(uiA) == 0xFF;
bool subnormalOrZero = expF16UI(uiA) == 0;
bool sign = signF16UI(uiA);
bool fracZero = fracF16UI(uiA) == 0;
bool isNaN = isNaNF16UI(uiA);
bool isSNaN = softfloat_isSigNaNF16UI(uiA);
return (sign && infOrNaN && fracZero) << 0 | (sign && !infOrNaN && !subnormalOrZero) << 1 |
(sign && subnormalOrZero && !fracZero) << 2 | (sign && subnormalOrZero && fracZero) << 3 | (!sign && infOrNaN && fracZero) << 7 |
(!sign && !infOrNaN && !subnormalOrZero) << 6 | (!sign && subnormalOrZero && !fracZero) << 5 |
(!sign && subnormalOrZero && fracZero) << 4 | (isNaN && isSNaN) << 8 | (isNaN && !isSNaN) << 9;
}
uint32_t fadd_s(uint32_t v1, uint32_t v2, uint8_t mode) {
float32_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float32_t r = f32_add(v1f, v2f);
return r.v;
}
uint32_t fsub_s(uint32_t v1, uint32_t v2, uint8_t mode) {
float32_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float32_t r = f32_sub(v1f, v2f);
return r.v;
}
uint32_t fmul_s(uint32_t v1, uint32_t v2, uint8_t mode) {
float32_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float32_t r = f32_mul(v1f, v2f);
return r.v;
}
uint32_t fdiv_s(uint32_t v1, uint32_t v2, uint8_t mode) {
float32_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float32_t r = f32_div(v1f, v2f);
return r.v;
}
uint32_t fsqrt_s(uint32_t v1, uint8_t mode) {
float32_t v1f{v1};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float32_t r = f32_sqrt(v1f);
return r.v;
}
uint32_t fcmp_s(uint32_t v1, uint32_t v2, uint32_t op) {
float32_t v1f{v1}, v2f{v2};
softfloat_exceptionFlags = 0;
bool nan = (v1 & defaultNaNF32UI) == quiet_nan32 || (v2 & defaultNaNF32UI) == quiet_nan32;
bool snan = softfloat_isSigNaNF32UI(v1) || softfloat_isSigNaNF32UI(v2);
switch(op) {
case 0:
if(nan | snan) {
if(snan)
softfloat_raiseFlags(softfloat_flag_invalid);
return 0;
} else
return f32_eq(v1f, v2f) ? 1 : 0;
case 1:
if(nan | snan) {
softfloat_raiseFlags(softfloat_flag_invalid);
return 0;
} else
return f32_le(v1f, v2f) ? 1 : 0;
case 2:
if(nan | snan) {
softfloat_raiseFlags(softfloat_flag_invalid);
return 0;
} else
return f32_lt(v1f, v2f) ? 1 : 0;
default:
break;
}
return -1;
}
uint32_t fcvt_s(uint32_t v1, uint32_t op, uint8_t mode) {
float32_t v1f{v1};
softfloat_exceptionFlags = 0;
float32_t r;
switch(op) {
case 0: { // FCVT__W__S
uint_fast32_t res = f32_to_i32(v1f, rmm_map.at(mode), true);
return (uint32_t)res;
}
case 1: { // FCVT__WU__S
uint_fast32_t res = f32_to_ui32(v1f, rmm_map.at(mode), true);
return (uint32_t)res;
}
case 2: // FCVT__S__W
r = i32_to_f32((int32_t)v1);
return r.v;
case 3: // FCVT__S__WU
r = ui32_to_f32(v1);
return r.v;
}
return 0;
}
uint32_t fmadd_s(uint32_t v1, uint32_t v2, uint32_t v3, uint32_t op, uint8_t mode) {
uint32_t F32_SIGN = 1UL << 31;
switch(op) {
case 0: // FMADD_S
break;
case 1: // FMSUB_S
v3 ^= F32_SIGN;
break;
case 2: // FNMADD_S
v1 ^= F32_SIGN;
v3 ^= F32_SIGN;
break;
case 3: // FNMSUB_S
v1 ^= F32_SIGN;
break;
}
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float32_t res = softfloat_mulAddF32(v1, v2, v3, 0);
return res.v;
}
uint32_t fsel_s(uint32_t v1, uint32_t v2, uint32_t op) {
softfloat_exceptionFlags = 0;
bool v1_nan = (v1 & defaultNaNF32UI) == defaultNaNF32UI;
bool v2_nan = (v2 & defaultNaNF32UI) == defaultNaNF32UI;
bool v1_snan = softfloat_isSigNaNF32UI(v1);
bool v2_snan = softfloat_isSigNaNF32UI(v2);
if(v1_snan || v2_snan)
softfloat_raiseFlags(softfloat_flag_invalid);
if(v1_nan || v1_snan)
return (v2_nan || v2_snan) ? defaultNaNF32UI : v2;
else if(v2_nan || v2_snan)
return v1;
else {
if((v1 & 0x7fffffff) == 0 && (v2 & 0x7fffffff) == 0) {
return op == 0 ? ((v1 & 0x80000000) ? v1 : v2) : ((v1 & 0x80000000) ? v2 : v1);
} else {
float32_t v1f{v1}, v2f{v2};
return op == 0 ? (f32_lt(v1f, v2f) ? v1 : v2) : (f32_lt(v1f, v2f) ? v2 : v1);
}
}
}
uint32_t fclass_s(uint32_t v1) {
float32_t a{v1};
union ui32_f32 uA;
uint_fast32_t uiA;
uA.f = a;
uiA = uA.ui;
bool infOrNaN = expF32UI(uiA) == 0xFF;
bool subnormalOrZero = expF32UI(uiA) == 0;
bool sign = signF32UI(uiA);
bool fracZero = fracF32UI(uiA) == 0;
bool isNaN = isNaNF32UI(uiA);
bool isSNaN = softfloat_isSigNaNF32UI(uiA);
return (sign && infOrNaN && fracZero) << 0 | (sign && !infOrNaN && !subnormalOrZero) << 1 |
(sign && subnormalOrZero && !fracZero) << 2 | (sign && subnormalOrZero && fracZero) << 3 | (!sign && infOrNaN && fracZero) << 7 |
(!sign && !infOrNaN && !subnormalOrZero) << 6 | (!sign && subnormalOrZero && !fracZero) << 5 |
(!sign && subnormalOrZero && fracZero) << 4 | (isNaN && isSNaN) << 8 | (isNaN && !isSNaN) << 9;
}
uint32_t fconv_d2f(uint64_t v1, uint8_t mode) {
if(softfloat_isSigNaNF64UI(v1)) {
softfloat_raiseFlags(softfloat_flag_invalid);
return defaultNaNF32UI;
} else {
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float32_t res = f64_to_f32(float64_t{v1});
return res.v;
}
}
uint64_t fconv_f2d(uint32_t v1, uint8_t mode) {
bool infOrNaN = expF32UI(v1) == 0xFF;
bool subnormalOrZero = expF32UI(v1) == 0;
if(infOrNaN || subnormalOrZero) {
return defaultNaNF64UI;
} else {
float64_t res = f32_to_f64(float32_t{v1});
return res.v;
}
}
uint64_t fadd_d(uint64_t v1, uint64_t v2, uint8_t mode) {
bool nan = (v1 & defaultNaNF32UI) == quiet_nan32;
bool snan = softfloat_isSigNaNF32UI(v1);
float64_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float64_t r = f64_add(v1f, v2f);
return r.v;
}
uint64_t fsub_d(uint64_t v1, uint64_t v2, uint8_t mode) {
float64_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float64_t r = f64_sub(v1f, v2f);
return r.v;
}
uint64_t fmul_d(uint64_t v1, uint64_t v2, uint8_t mode) {
float64_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float64_t r = f64_mul(v1f, v2f);
return r.v;
}
uint64_t fdiv_d(uint64_t v1, uint64_t v2, uint8_t mode) {
float64_t v1f{v1}, v2f{v2};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float64_t r = f64_div(v1f, v2f);
return r.v;
}
uint64_t fsqrt_d(uint64_t v1, uint8_t mode) {
float64_t v1f{v1};
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float64_t r = f64_sqrt(v1f);
return r.v;
}
uint64_t fcmp_d(uint64_t v1, uint64_t v2, uint32_t op) {
float64_t v1f{v1}, v2f{v2};
softfloat_exceptionFlags = 0;
bool nan = (v1 & defaultNaNF64UI) == quiet_nan32 || (v2 & defaultNaNF64UI) == quiet_nan32;
bool snan = softfloat_isSigNaNF64UI(v1) || softfloat_isSigNaNF64UI(v2);
switch(op) {
case 0:
if(nan | snan) {
if(snan)
softfloat_raiseFlags(softfloat_flag_invalid);
return 0;
} else
return f64_eq(v1f, v2f) ? 1 : 0;
case 1:
if(nan | snan) {
softfloat_raiseFlags(softfloat_flag_invalid);
return 0;
} else
return f64_le(v1f, v2f) ? 1 : 0;
case 2:
if(nan | snan) {
softfloat_raiseFlags(softfloat_flag_invalid);
return 0;
} else
return f64_lt(v1f, v2f) ? 1 : 0;
default:
break;
}
return -1;
}
uint64_t fcvt_d(uint64_t v1, uint32_t op, uint8_t mode) {
float64_t v1f{v1};
softfloat_exceptionFlags = 0;
float64_t r;
switch(op) {
case 0: { // l from d
int64_t res = f64_to_i64(v1f, rmm_map.at(mode), true);
return (uint64_t)res;
}
case 1: { // lu from d
uint64_t res = f64_to_ui64(v1f, rmm_map.at(mode), true);
return res;
}
case 2: // d from l
r = i64_to_f64(v1);
return r.v;
case 3: // d from lu
r = ui64_to_f64(v1);
return r.v;
}
return 0;
}
uint64_t fmadd_d(uint64_t v1, uint64_t v2, uint64_t v3, uint32_t op, uint8_t mode) {
uint64_t F64_SIGN = 1ULL << 63;
switch(op) {
case 0: // FMADD_D
break;
case 1: // FMSUB_D
v3 ^= F64_SIGN;
break;
case 2: // FNMADD_D
v1 ^= F64_SIGN;
v3 ^= F64_SIGN;
break;
case 3: // FNMSUB_D
v1 ^= F64_SIGN;
break;
}
softfloat_roundingMode = rmm_map.at(mode);
softfloat_exceptionFlags = 0;
float64_t res = softfloat_mulAddF64(v1, v2, v3, 0);
return res.v;
}
uint64_t fsel_d(uint64_t v1, uint64_t v2, uint32_t op) {
softfloat_exceptionFlags = 0;
bool v1_nan = (v1 & defaultNaNF64UI) == defaultNaNF64UI;
bool v2_nan = (v2 & defaultNaNF64UI) == defaultNaNF64UI;
bool v1_snan = softfloat_isSigNaNF64UI(v1);
bool v2_snan = softfloat_isSigNaNF64UI(v2);
if(v1_snan || v2_snan)
softfloat_raiseFlags(softfloat_flag_invalid);
if(v1_nan || v1_snan)
return (v2_nan || v2_snan) ? defaultNaNF64UI : v2;
else if(v2_nan || v2_snan)
return v1;
else {
if((v1 & std::numeric_limits<int64_t>::max()) == 0 && (v2 & std::numeric_limits<int64_t>::max()) == 0) {
return op == 0 ? ((v1 & std::numeric_limits<int64_t>::min()) ? v1 : v2)
: ((v1 & std::numeric_limits<int64_t>::min()) ? v2 : v1);
} else {
float64_t v1f{v1}, v2f{v2};
return op == 0 ? (f64_lt(v1f, v2f) ? v1 : v2) : (f64_lt(v1f, v2f) ? v2 : v1);
}
}
}
uint64_t fclass_d(uint64_t v1) {
float64_t a{v1};
union ui64_f64 uA;
uint_fast64_t uiA;
uA.f = a;
uiA = uA.ui;
bool infOrNaN = expF64UI(uiA) == 0x7FF;
bool subnormalOrZero = expF64UI(uiA) == 0;
bool sign = signF64UI(uiA);
bool fracZero = fracF64UI(uiA) == 0;
bool isNaN = isNaNF64UI(uiA);
bool isSNaN = softfloat_isSigNaNF64UI(uiA);
return (sign && infOrNaN && fracZero) << 0 | (sign && !infOrNaN && !subnormalOrZero) << 1 |
(sign && subnormalOrZero && !fracZero) << 2 | (sign && subnormalOrZero && fracZero) << 3 | (!sign && infOrNaN && fracZero) << 7 |
(!sign && !infOrNaN && !subnormalOrZero) << 6 | (!sign && subnormalOrZero && !fracZero) << 5 |
(!sign && subnormalOrZero && fracZero) << 4 | (isNaN && isSNaN) << 8 | (isNaN && !isSNaN) << 9;
}
uint64_t fcvt_32_64(uint32_t v1, uint32_t op, uint8_t mode) {
float32_t v1f{v1};
softfloat_exceptionFlags = 0;
float64_t r;
switch(op) {
case 0: // l->s, fp to int32
return f32_to_i64(v1f, rmm_map.at(mode), true);
case 1: // wu->s
return f32_to_ui64(v1f, rmm_map.at(mode), true);
case 2: // s->w
r = i32_to_f64(v1);
return r.v;
case 3: // s->wu
r = ui32_to_f64(v1);
return r.v;
}
return 0;
}
uint32_t fcvt_64_32(uint64_t v1, uint32_t op, uint8_t mode) {
softfloat_exceptionFlags = 0;
float32_t r;
switch(op) {
case 0: { // wu->s
int32_t r = f64_to_i32(float64_t{v1}, rmm_map.at(mode), true);
return r;
}
case 1: { // wu->s
uint32_t r = f64_to_ui32(float64_t{v1}, rmm_map.at(mode), true);
return r;
}
case 2: // l->s, fp to int32
r = i64_to_f32(v1);
return r.v;
case 3: // wu->s
r = ui64_to_f32(v1);
return r.v;
}
return 0;
}
uint32_t unbox_s(uint64_t v) {
constexpr uint64_t mask = std::numeric_limits<uint64_t>::max() & ~((uint64_t)std::numeric_limits<uint32_t>::max());
if((v & mask) != mask)
return 0x7fc00000;
else
return v & std::numeric_limits<uint32_t>::max();
}
}
template <typename T> T constexpr defaultNaN();
template <> uint16_t constexpr defaultNaN<uint16_t>() { return defaultNaNF16UI; }
template <> uint32_t constexpr defaultNaN<uint32_t>() { return defaultNaNF32UI; }
template <> uint64_t constexpr defaultNaN<uint64_t>() { return defaultNaNF64UI; }
template <typename T> T constexpr posInf();
template <> uint16_t constexpr posInf<uint16_t>() { return 0x7C00; }
template <> uint32_t constexpr posInf<uint32_t>() { return 0x7F800000; }
template <> uint64_t constexpr posInf<uint64_t>() { return 0x7FF0000000000000; }
template <typename T> T constexpr negInf();
template <> uint16_t constexpr negInf<uint16_t>() { return 0xFC00; }
template <> uint32_t constexpr negInf<uint32_t>() { return 0xFF800000; }
template <> uint64_t constexpr negInf<uint64_t>() { return 0xFFF0000000000000; }
template <typename T> T constexpr negZero();
template <> uint16_t constexpr negZero<uint16_t>() { return 0x8000; }
template <> uint32_t constexpr negZero<uint32_t>() { return 0x80000000; }
template <> uint64_t constexpr negZero<uint64_t>() { return 0x8000000000000000; }
template <typename T> bool rsqrt_check(T fclass_val, bool& subnormal, T& ret_val) {
softfloat_exceptionFlags = 0;
switch(fclass_val) {
case 0x0001: {
softfloat_exceptionFlags |= softfloat_flag_invalid;
ret_val = defaultNaN<T>();
return true;
}
case 0x0002: {
softfloat_exceptionFlags |= softfloat_flag_invalid;
ret_val = defaultNaN<T>();
return true;
}
case 0x0004: {
softfloat_exceptionFlags |= softfloat_flag_invalid;
ret_val = defaultNaN<T>();
return true;
}
case 0x0100: {
softfloat_exceptionFlags |= softfloat_flag_invalid;
ret_val = defaultNaN<T>();
return true;
}
case 0x0200: {
ret_val = defaultNaN<T>();
return true;
}
case 0x0008: {
softfloat_exceptionFlags |= softfloat_flag_infinite;
ret_val = negInf<T>();
return true;
}
case 0x0010: {
softfloat_exceptionFlags |= softfloat_flag_infinite;
ret_val = posInf<T>();
return true;
}
case 0x0080: {
ret_val = 0;
return true;
}
case 0x0020: {
subnormal = true;
}
default:
return false;
}
}
static constexpr std::array<std::array<uint64_t, 64>, 2> rsqrt_table{
{{
52, 51, 50, 48, 47, 46, 44, 43, 42, 41, 40, 39, 38, 36, 35, 34, 33, 32, 31, 30, 30, 29, 28, 27, 26, 25, 24, 23, 23, 22, 21, 20,
19, 19, 18, 17, 16, 16, 15, 14, 14, 13, 12, 12, 11, 10, 10, 9, 9, 8, 7, 7, 6, 6, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0,
},
{127, 125, 123, 121, 119, 118, 116, 114, 113, 111, 109, 108, 106, 105, 103, 102, 100, 99, 97, 96, 95, 93,
92, 91, 90, 88, 87, 86, 85, 84, 83, 82, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 70,
69, 68, 67, 66, 65, 64, 63, 63, 62, 61, 60, 59, 59, 58, 57, 56, 56, 55, 54, 53}}};
uint64_t constexpr frsqrt7_general(const unsigned s, const unsigned e, const uint64_t sign, const int64_t exp, const uint64_t sig,
const bool subnormal) {
int64_t normalized_exp = exp;
uint64_t normalized_sig = sig;
if(subnormal) {
signed nr_leadingzeros = __builtin_clzll(sig) - (64 - s);
normalized_exp = -nr_leadingzeros;
normalized_sig = (sig << (1 + nr_leadingzeros)) & ((1ULL << s) - 1);
}
unsigned exp_idx = normalized_exp & 1;
unsigned sig_idx = (normalized_sig >> (s - 6)) & 0x3f;
// The output of the table becomes the seven high bits of the result significand (after the leading one); the remainder of the
// result significand is zero.
uint64_t out_sig = rsqrt_table[exp_idx][sig_idx] << (s - 7);
// The output exponent equals floor((3*B - 1 - the normalized input exponent) / 2), where B is the exponent bias.
unsigned bias = (1UL << (e - 1)) - 1;
uint64_t out_exp = (3 * bias - 1 - normalized_exp) / 2;
// The output sign equals the input sign.
return (sign << (s + e)) | (out_exp << s) | out_sig;
}
uint16_t frsqrt7_h(uint16_t v) {
bool subnormal = false;
uint16_t ret_val = 0;
if(rsqrt_check(fclass_h(v), subnormal, ret_val)) {
return ret_val;
}
uint16_t sig = fracF64UI(v);
int16_t exp = expF64UI(v);
uint16_t sign = signF64UI(v);
unsigned constexpr e = 5;
unsigned constexpr s = 10;
return frsqrt7_general(s, e, sign, exp, sig, subnormal);
}
uint32_t frsqrt7_s(uint32_t v) {
bool subnormal = false;
uint32_t ret_val = 0;
if(rsqrt_check(fclass_s(v), subnormal, ret_val)) {
return ret_val;
}
uint32_t sig = fracF32UI(v);
int exp = expF32UI(v);
uint32_t sign = signF32UI(v);
unsigned constexpr e = 8;
unsigned constexpr s = 23;
return frsqrt7_general(s, e, sign, exp, sig, subnormal);
}
uint64_t frsqrt7_d(uint64_t v) {
bool subnormal = false;
uint64_t ret_val = 0;
if(rsqrt_check(fclass_d(v), subnormal, ret_val)) {
return ret_val;
}
uint64_t sig = fracF64UI(v);
int exp = expF64UI(v);
uint64_t sign = signF64UI(v);
unsigned constexpr e = 11;
unsigned constexpr s = 52;
return frsqrt7_general(s, e, sign, exp, sig, subnormal);
}
template <typename T> bool recip_check(T fclass_val, bool& subnormal, uint64_t& ret_val) {
softfloat_exceptionFlags = 0;
switch(fclass_val) {
case 0x0001: {
ret_val = negZero<T>();
return true;
}
case 0x0080: {
ret_val = 0;
return true;
}
case 0x0008: {
softfloat_exceptionFlags |= softfloat_flag_infinite;
ret_val = negInf<T>();
return true;
}
case 0x0010: {
softfloat_exceptionFlags |= softfloat_flag_infinite;
ret_val = posInf<T>();
return true;
}
case 0x0100: {
softfloat_exceptionFlags |= softfloat_flag_invalid;
ret_val = defaultNaN<T>();
return true;
}
case 0x0200: {
ret_val = defaultNaN<T>();
return true;
}
case 0x0004: {
subnormal = true;
return false;
}
case 0x0020: {
subnormal = true;
return false;
}
default: {
subnormal = false;
return false;
}
}
}
static constexpr std::array<uint64_t, 128> rec_table{
{127, 125, 123, 121, 119, 117, 116, 114, 112, 110, 109, 107, 105, 104, 102, 100, 99, 97, 96, 94, 93, 91, 90, 88, 87, 85,
84, 83, 81, 80, 79, 77, 76, 75, 74, 72, 71, 70, 69, 68, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55,
54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 40, 39, 38, 37, 36, 35, 35, 34, 33, 32, 31,
31, 30, 29, 28, 28, 27, 26, 25, 25, 24, 23, 23, 22, 21, 21, 20, 19, 19, 18, 17, 17, 16, 15, 15, 14, 14,
13, 12, 12, 11, 11, 10, 9, 9, 8, 8, 7, 7, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0}};
bool frec_general(uint64_t& res, const unsigned s, const unsigned e, const uint64_t sign, const int64_t exp, const uint64_t sig,
const bool subnormal, uint8_t mode) {
int nr_leadingzeros = __builtin_clzll(sig) - (64 - s);
int64_t normalized_exp = subnormal ? -nr_leadingzeros : exp;
uint64_t normalized_sig = subnormal ? ((sig << (1 + nr_leadingzeros)) & ((1ULL << s) - 1)) : sig;
unsigned idx = (normalized_sig >> (s - 7)) & 0x7f;
unsigned bias = (1UL << (e - 1)) - 1;
uint64_t mid_exp = 2 * (bias)-1 - normalized_exp;
uint64_t mid_sig = rec_table[idx] << (s - 7);
uint64_t out_exp = mid_exp;
uint64_t out_sig = mid_sig;
if(mid_exp == 0) {
out_exp = mid_exp;
out_sig = (mid_sig >> 1) | (1ULL << (s - 1));
} else if(mid_exp == (1ULL << e) - 1) {
out_exp = 0;
out_sig = (mid_sig >> 2) | (1ULL << (s - 2));
}
if(subnormal && nr_leadingzeros > 1) {
if((mode == 0b001) || (mode == 0b010 && sign == 0b0) || (mode == 0b011 && sign == 0b1)) {
res = (sign << (s + e)) | ((1ULL << (e - 1)) - 1) << s | ((1ULL << s) - 1);
return true;
} else {
res = (sign << (s + e)) | ((1ULL << e) - 1) << s;
return true;
}
}
res = (sign << (s + e)) | (out_exp << s) | out_sig;
return false;
}
uint16_t frec7_h(uint16_t v, uint8_t mode) {
bool subnormal = false;
uint64_t ret_val = 0;
if(recip_check(fclass_h(v), subnormal, ret_val)) {
return ret_val;
}
uint16_t sig = fracF16UI(v);
int exp = expF16UI(v);
uint16_t sign = signF16UI(v);
unsigned constexpr e = 5;
unsigned constexpr s = 10;
if(frec_general(ret_val, s, e, sign, exp, sig, subnormal, mode))
softfloat_exceptionFlags |= (softfloat_flag_inexact | softfloat_flag_overflow);
return ret_val;
}
uint32_t frec7_s(uint32_t v, uint8_t mode) {
bool subnormal = false;
uint64_t ret_val = 0;
if(recip_check(fclass_s(v), subnormal, ret_val)) {
return ret_val;
}
uint32_t sig = fracF32UI(v);
int exp = expF32UI(v);
uint32_t sign = signF32UI(v);
unsigned constexpr e = 8;
unsigned constexpr s = 23;
if(frec_general(ret_val, s, e, sign, exp, sig, subnormal, mode))
softfloat_exceptionFlags |= (softfloat_flag_inexact | softfloat_flag_overflow);
return ret_val;
}
uint64_t frec7_d(uint64_t v, uint8_t mode) {
bool subnormal = false;
uint64_t ret_val = 0;
if(recip_check(fclass_d(v), subnormal, ret_val)) {
return ret_val;
}
uint64_t sig = fracF64UI(v);
int exp = expF64UI(v);
uint64_t sign = signF64UI(v);
unsigned constexpr e = 11;
unsigned constexpr s = 52;
if(frec_general(ret_val, s, e, sign, exp, sig, subnormal, mode))
softfloat_exceptionFlags |= (softfloat_flag_inexact | softfloat_flag_overflow);
return ret_val;
}