Commit c02e1fb8 authored by Alex Bennée's avatar Alex Bennée
Browse files

fpu/softfloat: re-factor int/uint to float 



These are considerably simpler as the lower order integers can just
use the higher order conversion function. As the decomposed fractional
part is a full 64 bit rounding and inexact handling comes from the
pack functions.

Signed-off-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
parent ab52f973

fpu/softfloat.c

+163 −159
Original line number Diff line number Diff line
@@ -1500,6 +1500,169 @@ FLOAT_TO_UINT(64, 64) 


#undef FLOAT_TO_UINT



/*

 * Integer to float conversions

 *

 * Returns the result of converting the two's complement integer `a'

 * to the floating-point format. The conversion is performed according

 * to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.

 */



static FloatParts int_to_float(int64_t a, float_status *status)

{

    FloatParts r;

    if (a == 0) {

        r.cls = float_class_zero;

        r.sign = false;

    } else if (a == (1ULL << 63)) {

        r.cls = float_class_normal;

        r.sign = true;

        r.frac = DECOMPOSED_IMPLICIT_BIT;

        r.exp = 63;

    } else {

        uint64_t f;

        if (a < 0) {

            f = -a;

            r.sign = true;

        } else {

            f = a;

            r.sign = false;

        }

        int shift = clz64(f) - 1;

        r.cls = float_class_normal;

        r.exp = (DECOMPOSED_BINARY_POINT - shift);

        r.frac = f << shift;

    }



    return r;

}



float16 int64_to_float16(int64_t a, float_status *status)

{

    FloatParts pa = int_to_float(a, status);

    return float16_round_pack_canonical(pa, status);

}



float16 int32_to_float16(int32_t a, float_status *status)

{

    return int64_to_float16(a, status);

}



float16 int16_to_float16(int16_t a, float_status *status)

{

    return int64_to_float16(a, status);

}



float32 int64_to_float32(int64_t a, float_status *status)

{

    FloatParts pa = int_to_float(a, status);

    return float32_round_pack_canonical(pa, status);

}



float32 int32_to_float32(int32_t a, float_status *status)

{

    return int64_to_float32(a, status);

}



float32 int16_to_float32(int16_t a, float_status *status)

{

    return int64_to_float32(a, status);

}



float64 int64_to_float64(int64_t a, float_status *status)

{

    FloatParts pa = int_to_float(a, status);

    return float64_round_pack_canonical(pa, status);

}



float64 int32_to_float64(int32_t a, float_status *status)

{

    return int64_to_float64(a, status);

}



float64 int16_to_float64(int16_t a, float_status *status)

{

    return int64_to_float64(a, status);

}





/*

 * Unsigned Integer to float conversions

 *

 * Returns the result of converting the unsigned integer `a' to the

 * floating-point format. The conversion is performed according to the

 * IEC/IEEE Standard for Binary Floating-Point Arithmetic.

 */



static FloatParts uint_to_float(uint64_t a, float_status *status)

{

    FloatParts r = { .sign = false};



    if (a == 0) {

        r.cls = float_class_zero;

    } else {

        int spare_bits = clz64(a) - 1;

        r.cls = float_class_normal;

        r.exp = DECOMPOSED_BINARY_POINT - spare_bits;

        if (spare_bits < 0) {

            shift64RightJamming(a, -spare_bits, &a);

            r.frac = a;

        } else {

            r.frac = a << spare_bits;

        }

    }



    return r;

}



float16 uint64_to_float16(uint64_t a, float_status *status)

{

    FloatParts pa = uint_to_float(a, status);

    return float16_round_pack_canonical(pa, status);

}



float16 uint32_to_float16(uint32_t a, float_status *status)

{

    return uint64_to_float16(a, status);

}



float16 uint16_to_float16(uint16_t a, float_status *status)

{

    return uint64_to_float16(a, status);

}



float32 uint64_to_float32(uint64_t a, float_status *status)

{

    FloatParts pa = uint_to_float(a, status);

    return float32_round_pack_canonical(pa, status);

}



float32 uint32_to_float32(uint32_t a, float_status *status)

{

    return uint64_to_float32(a, status);

}



float32 uint16_to_float32(uint16_t a, float_status *status)

{

    return uint64_to_float32(a, status);

}



float64 uint64_to_float64(uint64_t a, float_status *status)

{

    FloatParts pa = uint_to_float(a, status);

    return float64_round_pack_canonical(pa, status);

}



float64 uint32_to_float64(uint32_t a, float_status *status)

{

    return uint64_to_float64(a, status);

}



float64 uint16_to_float64(uint16_t a, float_status *status)

{

    return uint64_to_float64(a, status);

}



/*----------------------------------------------------------------------------

| Takes a 64-bit fixed-point value `absZ' with binary point between bits 6

| and 7, and returns the properly rounded 32-bit integer corresponding to the
@@ -2591,43 +2754,6 @@ static float128 normalizeRoundAndPackFloat128(flag zSign, int32_t zExp, 


}



/*----------------------------------------------------------------------------

| Returns the result of converting the 32-bit two's complement integer `a'

| to the single-precision floating-point format.  The conversion is performed

| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.

*----------------------------------------------------------------------------*/



float32 int32_to_float32(int32_t a, float_status *status)

{

    flag zSign;



    if ( a == 0 ) return float32_zero;

    if ( a == (int32_t) 0x80000000 ) return packFloat32( 1, 0x9E, 0 );

    zSign = ( a < 0 );

    return normalizeRoundAndPackFloat32(zSign, 0x9C, zSign ? -a : a, status);

}



/*----------------------------------------------------------------------------

| Returns the result of converting the 32-bit two's complement integer `a'

| to the double-precision floating-point format.  The conversion is performed

| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.

*----------------------------------------------------------------------------*/



float64 int32_to_float64(int32_t a, float_status *status)

{

    flag zSign;

    uint32_t absA;

    int8_t shiftCount;

    uint64_t zSig;



    if ( a == 0 ) return float64_zero;

    zSign = ( a < 0 );

    absA = zSign ? - a : a;

    shiftCount = countLeadingZeros32( absA ) + 21;

    zSig = absA;

    return packFloat64( zSign, 0x432 - shiftCount, zSig<<shiftCount );



}



/*----------------------------------------------------------------------------

| Returns the result of converting the 32-bit two's complement integer `a'
@@ -2674,56 +2800,6 @@ float128 int32_to_float128(int32_t a, float_status *status) 


}



/*----------------------------------------------------------------------------

| Returns the result of converting the 64-bit two's complement integer `a'

| to the single-precision floating-point format.  The conversion is performed

| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.

*----------------------------------------------------------------------------*/



float32 int64_to_float32(int64_t a, float_status *status)

{

    flag zSign;

    uint64_t absA;

    int8_t shiftCount;



    if ( a == 0 ) return float32_zero;

    zSign = ( a < 0 );

    absA = zSign ? - a : a;

    shiftCount = countLeadingZeros64( absA ) - 40;

    if ( 0 <= shiftCount ) {

        return packFloat32( zSign, 0x95 - shiftCount, absA<<shiftCount );

    }

    else {

        shiftCount += 7;

        if ( shiftCount < 0 ) {

            shift64RightJamming( absA, - shiftCount, &absA );

        }

        else {

            absA <<= shiftCount;

        }

        return roundAndPackFloat32(zSign, 0x9C - shiftCount, absA, status);

    }



}



/*----------------------------------------------------------------------------

| Returns the result of converting the 64-bit two's complement integer `a'

| to the double-precision floating-point format.  The conversion is performed

| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.

*----------------------------------------------------------------------------*/



float64 int64_to_float64(int64_t a, float_status *status)

{

    flag zSign;



    if ( a == 0 ) return float64_zero;

    if ( a == (int64_t) LIT64( 0x8000000000000000 ) ) {

        return packFloat64( 1, 0x43E, 0 );

    }

    zSign = ( a < 0 );

    return normalizeRoundAndPackFloat64(zSign, 0x43C, zSign ? -a : a, status);

}



/*----------------------------------------------------------------------------

| Returns the result of converting the 64-bit two's complement integer `a'

| to the extended double-precision floating-point format.  The conversion
@@ -2778,65 +2854,6 @@ float128 int64_to_float128(int64_t a, float_status *status) 


}



/*----------------------------------------------------------------------------

| Returns the result of converting the 64-bit unsigned integer `a'

| to the single-precision floating-point format.  The conversion is performed

| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.

*----------------------------------------------------------------------------*/



float32 uint64_to_float32(uint64_t a, float_status *status)

{

    int shiftcount;



    if (a == 0) {

        return float32_zero;

    }



    /* Determine (left) shift needed to put first set bit into bit posn 23

     * (since packFloat32() expects the binary point between bits 23 and 22);

     * this is the fast case for smallish numbers.

     */

    shiftcount = countLeadingZeros64(a) - 40;

    if (shiftcount >= 0) {

        return packFloat32(0, 0x95 - shiftcount, a << shiftcount);

    }

    /* Otherwise we need to do a round-and-pack. roundAndPackFloat32()

     * expects the binary point between bits 30 and 29, hence the + 7.

     */

    shiftcount += 7;

    if (shiftcount < 0) {

        shift64RightJamming(a, -shiftcount, &a);

    } else {

        a <<= shiftcount;

    }



    return roundAndPackFloat32(0, 0x9c - shiftcount, a, status);

}



/*----------------------------------------------------------------------------

| Returns the result of converting the 64-bit unsigned integer `a'

| to the double-precision floating-point format.  The conversion is performed

| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.

*----------------------------------------------------------------------------*/



float64 uint64_to_float64(uint64_t a, float_status *status)

{

    int exp = 0x43C;

    int shiftcount;



    if (a == 0) {

        return float64_zero;

    }



    shiftcount = countLeadingZeros64(a) - 1;

    if (shiftcount < 0) {

        shift64RightJamming(a, -shiftcount, &a);

    } else {

        a <<= shiftcount;

    }

    return roundAndPackFloat64(0, exp - shiftcount, a, status);

}



/*----------------------------------------------------------------------------

| Returns the result of converting the 64-bit unsigned integer `a'

| to the quadruple-precision floating-point format.  The conversion is performed
@@ -6714,19 +6731,6 @@ int float128_unordered_quiet(float128 a, float128 b, float_status *status) 
    return 0;

}



/* misc functions */

float32 uint32_to_float32(uint32_t a, float_status *status)

{

    return int64_to_float32(a, status);

}



float64 uint32_to_float64(uint32_t a, float_status *status)

{

    return int64_to_float64(a, status);

}







#define COMPARE(s, nan_exp)                                                  \

static inline int float ## s ## _compare_internal(float ## s a, float ## s b,\

                                      int is_quiet, float_status *status)    \

include/fpu/softfloat.h

+9 −21
Original line number Diff line number Diff line
@@ -190,9 +190,13 @@ enum { 
/*----------------------------------------------------------------------------

| Software IEC/IEEE integer-to-floating-point conversion routines.

*----------------------------------------------------------------------------*/

float32 int16_to_float32(int16_t, float_status *status);

float32 int32_to_float32(int32_t, float_status *status);

float64 int16_to_float64(int16_t, float_status *status);

float64 int32_to_float64(int32_t, float_status *status);

float32 uint16_to_float32(uint16_t, float_status *status);

float32 uint32_to_float32(uint32_t, float_status *status);

float64 uint16_to_float64(uint16_t, float_status *status);

float64 uint32_to_float64(uint32_t, float_status *status);

floatx80 int32_to_floatx80(int32_t, float_status *status);

float128 int32_to_float128(int32_t, float_status *status);
@@ -204,27 +208,6 @@ float32 uint64_to_float32(uint64_t, float_status *status); 
float64 uint64_to_float64(uint64_t, float_status *status);

float128 uint64_to_float128(uint64_t, float_status *status);



/* We provide the int16 versions for symmetry of API with float-to-int */

static inline float32 int16_to_float32(int16_t v, float_status *status)

{

    return int32_to_float32(v, status);

}



static inline float32 uint16_to_float32(uint16_t v, float_status *status)

{

    return uint32_to_float32(v, status);

}



static inline float64 int16_to_float64(int16_t v, float_status *status)

{

    return int32_to_float64(v, status);

}



static inline float64 uint16_to_float64(uint16_t v, float_status *status)

{

    return uint32_to_float64(v, status);

}



/*----------------------------------------------------------------------------

| Software half-precision conversion routines.

*----------------------------------------------------------------------------*/
@@ -245,6 +228,11 @@ uint64_t float16_to_uint64(float16 a, float_status *status); 
int64_t float16_to_int64_round_to_zero(float16, float_status *status);

uint64_t float16_to_uint64_round_to_zero(float16 a, float_status *status);

float16 int16_to_float16(int16_t a, float_status *status);

float16 int32_to_float16(int32_t a, float_status *status);

float16 int64_to_float16(int64_t a, float_status *status);

float16 uint16_to_float16(uint16_t a, float_status *status);

float16 uint32_to_float16(uint32_t a, float_status *status);

float16 uint64_to_float16(uint64_t a, float_status *status);



/*----------------------------------------------------------------------------

| Software half-precision operations.