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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: Andrew Dutcher <andrew@andrewdutcher.com>
Reviewed-by: Peter 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: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Andrew Dutcher 2016-08-16 17:14:55 -07:00 committed by Peter Maydell
parent 9e8204b1de
commit d1eb8f2acb
2 changed files with 115 additions and 16 deletions
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116
fpu/softfloat.c
View File

@ -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 );
@ -5620,10 +5676,11 @@ floatx80 floatx80_sqrt(floatx80 a, float_status *status)
int floatx80_eq(floatx80 a, floatx80 b, float_status *status)
{
if ( ( ( extractFloatx80Exp( a ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( a )<<1 ) )
|| ( ( extractFloatx80Exp( b ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( b )<<1 ) )
if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)
|| (extractFloatx80Exp(a) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(a) << 1))
|| (extractFloatx80Exp(b) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(b) << 1))
) {
float_raise(float_flag_invalid, status);
return 0;
@ -5649,10 +5706,11 @@ int floatx80_le(floatx80 a, floatx80 b, float_status *status)
{
flag aSign, bSign;
if ( ( ( extractFloatx80Exp( a ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( a )<<1 ) )
|| ( ( extractFloatx80Exp( b ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( b )<<1 ) )
if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)
|| (extractFloatx80Exp(a) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(a) << 1))
|| (extractFloatx80Exp(b) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(b) << 1))
) {
float_raise(float_flag_invalid, status);
return 0;
@ -5682,10 +5740,11 @@ int floatx80_lt(floatx80 a, floatx80 b, float_status *status)
{
flag aSign, bSign;
if ( ( ( extractFloatx80Exp( a ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( a )<<1 ) )
|| ( ( extractFloatx80Exp( b ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( b )<<1 ) )
if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)
|| (extractFloatx80Exp(a) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(a) << 1))
|| (extractFloatx80Exp(b) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(b) << 1))
) {
float_raise(float_flag_invalid, status);
return 0;
@ -5712,10 +5771,11 @@ int floatx80_lt(floatx80 a, floatx80 b, float_status *status)
*----------------------------------------------------------------------------*/
int floatx80_unordered(floatx80 a, floatx80 b, float_status *status)
{
if ( ( ( extractFloatx80Exp( a ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( a )<<1 ) )
|| ( ( extractFloatx80Exp( b ) == 0x7FFF )
&& (uint64_t) ( extractFloatx80Frac( b )<<1 ) )
if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)
|| (extractFloatx80Exp(a) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(a) << 1))
|| (extractFloatx80Exp(b) == 0x7FFF
&& (uint64_t) (extractFloatx80Frac(b) << 1))
) {
float_raise(float_flag_invalid, status);
return 1;
@ -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 );

15
include/fpu/softfloat.h
View File

@ -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)