You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
74 lines
2.0 KiB
74 lines
2.0 KiB
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
#include "platform.h"
|
|
#include "primitives.h"
|
|
#include "internals.h"
|
|
#include "specialize.h"
|
|
#include "softfloat.h"
|
|
|
|
float64_t f64_sqrt( float64_t a )
|
|
{
|
|
union ui64_f64 uA;
|
|
uint_fast64_t uiA;
|
|
bool signA;
|
|
int_fast16_t expA;
|
|
uint_fast64_t sigA, uiZ;
|
|
struct exp16_sig64 normExpSig;
|
|
int_fast16_t expZ;
|
|
uint_fast32_t sigZ32;
|
|
uint_fast64_t sigZ;
|
|
struct uint128 term, rem;
|
|
union ui64_f64 uZ;
|
|
|
|
uA.f = a;
|
|
uiA = uA.ui;
|
|
signA = signF64UI( uiA );
|
|
expA = expF64UI( uiA );
|
|
sigA = fracF64UI( uiA );
|
|
if ( expA == 0x7FF ) {
|
|
if ( sigA ) {
|
|
uiZ = softfloat_propagateNaNF64UI( uiA, 0 );
|
|
goto uiZ;
|
|
}
|
|
if ( ! signA ) return a;
|
|
goto invalid;
|
|
}
|
|
if ( signA ) {
|
|
if ( ! ( expA | sigA ) ) return a;
|
|
goto invalid;
|
|
}
|
|
if ( ! expA ) {
|
|
if ( ! sigA ) return a;
|
|
normExpSig = softfloat_normSubnormalF64Sig( sigA );
|
|
expA = normExpSig.exp;
|
|
sigA = normExpSig.sig;
|
|
}
|
|
expZ = ( ( expA - 0x3FF )>>1 ) + 0x3FE;
|
|
sigA |= UINT64_C( 0x0010000000000000 );
|
|
sigZ32 = softfloat_estimateSqrt32( expA, sigA>>21 );
|
|
sigA <<= 9 - ( expA & 1 );
|
|
sigZ =
|
|
softfloat_estimateDiv128To64( sigA, 0, (uint_fast64_t) sigZ32<<32 )
|
|
+ ( (uint_fast64_t) sigZ32<<30 );
|
|
if ( ( sigZ & 0x1FF ) <= 5 ) {
|
|
term = softfloat_mul64To128( sigZ, sigZ );
|
|
rem = softfloat_sub128( sigA, 0, term.v64, term.v0 );
|
|
while ( UINT64_C( 0x8000000000000000 ) <= rem.v64 ) {
|
|
--sigZ;
|
|
rem =
|
|
softfloat_add128(
|
|
rem.v64, rem.v0, sigZ>>63, (uint64_t) ( sigZ<<1 ) );
|
|
}
|
|
sigZ |= ( ( rem.v64 | rem.v0 ) != 0 );
|
|
}
|
|
return softfloat_roundPackToF64( 0, expZ, sigZ );
|
|
invalid:
|
|
softfloat_raiseFlags( softfloat_flag_invalid );
|
|
uiZ = defaultNaNF64UI;
|
|
uiZ:
|
|
uZ.ui = uiZ;
|
|
return uZ.f;
|
|
|
|
}
|
|
|
|
|