expands floating point functions

This commit is contained in:
Eyck-Alexander Jentzsch 2025-03-03 19:39:29 +01:00
parent 8746003d3e
commit cd358198ad
2 changed files with 296 additions and 0 deletions

View File

@ -56,6 +56,28 @@ extern "C" {
uint32_t fget_flags() { return softfloat_exceptionFlags & 0x1f; }
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);
@ -455,3 +477,271 @@ uint32_t unbox_s(uint64_t v) {
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; }
/*
function nxFlag() -> bits(5) = 0b_00001 softfloat_flag_inexact = 1,
function ufFlag() -> bits(5) = 0b_00010 softfloat_flag_underflow = 2,
function ofFlag() -> bits(5) = 0b_00100 softfloat_flag_overflow = 4,
function dzFlag() -> bits(5) = 0b_01000 softfloat_flag_infinite = 8,
function nvFlag() -> bits(5) = 0b_10000 softfloat_flag_invalid = 16
*/
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) {
unsigned 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);
uint64_t out_exp = (3 * (bias - 1) - 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 = 58;
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);
uint64_t mid_exp = 2 * (bias - 1) - 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_s(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 = 58;
if(frec_general(ret_val, s, e, sign, exp, sig, subnormal, mode))
softfloat_exceptionFlags |= (softfloat_flag_inexact | softfloat_flag_overflow);
return ret_val;
}

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@ -39,6 +39,8 @@
extern "C" {
uint32_t fget_flags();
uint16_t frsqrt7_h(uint16_t v);
uint16_t frec7_h(uint16_t v, uint8_t mode);
uint32_t fadd_s(uint32_t v1, uint32_t v2, uint8_t mode);
uint32_t fsub_s(uint32_t v1, uint32_t v2, uint8_t mode);
uint32_t fmul_s(uint32_t v1, uint32_t v2, uint8_t mode);
@ -49,6 +51,8 @@ uint32_t fcvt_s(uint32_t v1, uint32_t op, uint8_t mode);
uint32_t fmadd_s(uint32_t v1, uint32_t v2, uint32_t v3, uint32_t op, uint8_t mode);
uint32_t fsel_s(uint32_t v1, uint32_t v2, uint32_t op);
uint32_t fclass_s(uint32_t v1);
uint32_t frsqrt7_s(uint32_t v);
uint32_t frec7_s(uint32_t v, uint8_t mode);
uint32_t fconv_d2f(uint64_t v1, uint8_t mode);
uint64_t fconv_f2d(uint32_t v1, uint8_t mode);
uint64_t fadd_d(uint64_t v1, uint64_t v2, uint8_t mode);
@ -61,6 +65,8 @@ uint64_t fcvt_d(uint64_t v1, uint32_t op, uint8_t mode);
uint64_t fmadd_d(uint64_t v1, uint64_t v2, uint64_t v3, uint32_t op, uint8_t mode);
uint64_t fsel_d(uint64_t v1, uint64_t v2, uint32_t op);
uint64_t fclass_d(uint64_t v1);
uint64_t frsqrt7_d(uint64_t v);
uint64_t frec7_d(uint64_t v, uint8_t mode);
uint64_t fcvt_32_64(uint32_t v1, uint32_t op, uint8_t mode);
uint32_t fcvt_64_32(uint64_t v1, uint32_t op, uint8_t mode);
uint32_t unbox_s(uint64_t v);