Commit d1eb8f2a authored by Andrew Dutcher's avatar Andrew Dutcher Committed by Peter Maydell
Browse files

fpu: add mechanism to check for invalid long double formats 



All operations that take a floatx80 as an operand need to have their
inputs checked for malformed encodings. In all of these cases, use the
function floatx80_invalid_encoding to perform the check. If an invalid
operand is found, raise an invalid operation exception, and then return
either NaN (for fp-typed results) or the integer indefinite value (the
minimum representable signed integer value, for int-typed results).

For the non-quiet comparison operations, this touches adjacent code in
order to pass style checks.

Signed-off-by: default avatarAndrew Dutcher <andrew@andrewdutcher.com>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-id: 1471392895-17324-1-git-send-email-andrew@andrewdutcher.com
[PMM: changed "1 << 63" to "1ULL << 63" to fix compile errors]
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent 9e8204b1

fpu/softfloat.c

+100 −16
Original line number Diff line number Diff line
@@ -4814,6 +4814,10 @@ int32_t floatx80_to_int32(floatx80 a, float_status *status) 
    int32_t aExp, shiftCount;

    uint64_t aSig;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return 1 << 31;

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -4842,6 +4846,10 @@ int32_t floatx80_to_int32_round_to_zero(floatx80 a, float_status *status) 
    uint64_t aSig, savedASig;

    int32_t z;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return 1 << 31;

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -4888,6 +4896,10 @@ int64_t floatx80_to_int64(floatx80 a, float_status *status) 
    int32_t aExp, shiftCount;

    uint64_t aSig, aSigExtra;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return 1ULL << 63;

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -4929,6 +4941,10 @@ int64_t floatx80_to_int64_round_to_zero(floatx80 a, float_status *status) 
    uint64_t aSig;

    int64_t z;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return 1ULL << 63;

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -4971,6 +4987,10 @@ float32 floatx80_to_float32(floatx80 a, float_status *status) 
    int32_t aExp;

    uint64_t aSig;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return float32_default_nan(status);

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -4999,6 +5019,10 @@ float64 floatx80_to_float64(floatx80 a, float_status *status) 
    int32_t aExp;

    uint64_t aSig, zSig;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return float64_default_nan(status);

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -5027,6 +5051,10 @@ float128 floatx80_to_float128(floatx80 a, float_status *status) 
    int aExp;

    uint64_t aSig, zSig0, zSig1;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return float128_default_nan(status);

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -5052,6 +5080,10 @@ floatx80 floatx80_round_to_int(floatx80 a, float_status *status) 
    uint64_t lastBitMask, roundBitsMask;

    floatx80 z;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aExp = extractFloatx80Exp( a );

    if ( 0x403E <= aExp ) {

        if ( ( aExp == 0x7FFF ) && (uint64_t) ( extractFloatx80Frac( a )<<1 ) ) {
@@ -5279,6 +5311,10 @@ floatx80 floatx80_add(floatx80 a, floatx80 b, float_status *status) 
{

    flag aSign, bSign;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aSign = extractFloatx80Sign( a );

    bSign = extractFloatx80Sign( b );

    if ( aSign == bSign ) {
@@ -5300,6 +5336,10 @@ floatx80 floatx80_sub(floatx80 a, floatx80 b, float_status *status) 
{

    flag aSign, bSign;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aSign = extractFloatx80Sign( a );

    bSign = extractFloatx80Sign( b );

    if ( aSign == bSign ) {
@@ -5323,6 +5363,10 @@ floatx80 floatx80_mul(floatx80 a, floatx80 b, float_status *status) 
    int32_t aExp, bExp, zExp;

    uint64_t aSig, bSig, zSig0, zSig1;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -5380,6 +5424,10 @@ floatx80 floatx80_div(floatx80 a, floatx80 b, float_status *status) 
    uint64_t aSig, bSig, zSig0, zSig1;

    uint64_t rem0, rem1, rem2, term0, term1, term2;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -5461,6 +5509,10 @@ floatx80 floatx80_rem(floatx80 a, floatx80 b, float_status *status) 
    uint64_t aSig0, aSig1, bSig;

    uint64_t q, term0, term1, alternateASig0, alternateASig1;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aSig0 = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -5556,6 +5608,10 @@ floatx80 floatx80_sqrt(floatx80 a, float_status *status) 
    uint64_t aSig0, aSig1, zSig0, zSig1, doubleZSig0;

    uint64_t rem0, rem1, rem2, rem3, term0, term1, term2, term3;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aSig0 = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );
@@ -5620,9 +5676,10 @@ floatx80 floatx80_sqrt(floatx80 a, float_status *status) 
int floatx80_eq(floatx80 a, floatx80 b, float_status *status)

{



    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)

        || (extractFloatx80Exp(a) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(a) << 1))

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )

        || (extractFloatx80Exp(b) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(b) << 1))

       ) {

        float_raise(float_flag_invalid, status);
@@ -5649,9 +5706,10 @@ int floatx80_le(floatx80 a, floatx80 b, float_status *status) 
{

    flag aSign, bSign;



    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)

        || (extractFloatx80Exp(a) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(a) << 1))

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )

        || (extractFloatx80Exp(b) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(b) << 1))

       ) {

        float_raise(float_flag_invalid, status);
@@ -5682,9 +5740,10 @@ int floatx80_lt(floatx80 a, floatx80 b, float_status *status) 
{

    flag aSign, bSign;



    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)

        || (extractFloatx80Exp(a) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(a) << 1))

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )

        || (extractFloatx80Exp(b) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(b) << 1))

       ) {

        float_raise(float_flag_invalid, status);
@@ -5712,9 +5771,10 @@ int floatx80_lt(floatx80 a, floatx80 b, float_status *status) 
*----------------------------------------------------------------------------*/

int floatx80_unordered(floatx80 a, floatx80 b, float_status *status)

{

    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)

        || (extractFloatx80Exp(a) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(a) << 1))

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )

        || (extractFloatx80Exp(b) == 0x7FFF

            && (uint64_t) (extractFloatx80Frac(b) << 1))

       ) {

        float_raise(float_flag_invalid, status);
@@ -5733,6 +5793,10 @@ int floatx80_unordered(floatx80 a, floatx80 b, float_status *status) 
int floatx80_eq_quiet(floatx80 a, floatx80 b, float_status *status)

{



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return 0;

    }

    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

              && (uint64_t) ( extractFloatx80Frac( a )<<1 ) )

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )
@@ -5764,6 +5828,10 @@ int floatx80_le_quiet(floatx80 a, floatx80 b, float_status *status) 
{

    flag aSign, bSign;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return 0;

    }

    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

              && (uint64_t) ( extractFloatx80Frac( a )<<1 ) )

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )
@@ -5800,6 +5868,10 @@ int floatx80_lt_quiet(floatx80 a, floatx80 b, float_status *status) 
{

    flag aSign, bSign;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return 0;

    }

    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

              && (uint64_t) ( extractFloatx80Frac( a )<<1 ) )

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )
@@ -5833,6 +5905,10 @@ int floatx80_lt_quiet(floatx80 a, floatx80 b, float_status *status) 
*----------------------------------------------------------------------------*/

int floatx80_unordered_quiet(floatx80 a, floatx80 b, float_status *status)

{

    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return 1;

    }

    if (    (    ( extractFloatx80Exp( a ) == 0x7FFF )

              && (uint64_t) ( extractFloatx80Frac( a )<<1 ) )

         || (    ( extractFloatx80Exp( b ) == 0x7FFF )
@@ -7374,6 +7450,10 @@ static inline int floatx80_compare_internal(floatx80 a, floatx80 b, 
{

    flag aSign, bSign;



    if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {

        float_raise(float_flag_invalid, status);

        return float_relation_unordered;

    }

    if (( ( extractFloatx80Exp( a ) == 0x7fff ) &&

          ( extractFloatx80Frac( a )<<1 ) ) ||

        ( ( extractFloatx80Exp( b ) == 0x7fff ) &&
@@ -7645,6 +7725,10 @@ floatx80 floatx80_scalbn(floatx80 a, int n, float_status *status) 
    int32_t aExp;

    uint64_t aSig;



    if (floatx80_invalid_encoding(a)) {

        float_raise(float_flag_invalid, status);

        return floatx80_default_nan(status);

    }

    aSig = extractFloatx80Frac( a );

    aExp = extractFloatx80Exp( a );

    aSign = extractFloatx80Sign( a );

include/fpu/softfloat.h

+15 −0
Original line number Diff line number Diff line
@@ -658,6 +658,21 @@ static inline int floatx80_is_any_nan(floatx80 a) 
    return ((a.high & 0x7fff) == 0x7fff) && (a.low<<1);

}



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

| Return whether the given value is an invalid floatx80 encoding.

| Invalid floatx80 encodings arise when the integer bit is not set, but

| the exponent is not zero. The only times the integer bit is permitted to

| be zero is in subnormal numbers and the value zero.

| This includes what the Intel software developer's manual calls pseudo-NaNs,

| pseudo-infinities and un-normal numbers. It does not include

| pseudo-denormals, which must still be correctly handled as inputs even

| if they are never generated as outputs.

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

static inline bool floatx80_invalid_encoding(floatx80 a)

{

    return (a.low & (1ULL << 63)) == 0 && (a.high & 0x7FFF) != 0;

}



#define floatx80_zero make_floatx80(0x0000, 0x0000000000000000LL)

#define floatx80_one make_floatx80(0x3fff, 0x8000000000000000LL)

#define floatx80_ln2 make_floatx80(0x3ffe, 0xb17217f7d1cf79acLL)