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authorPeter Maydell <peter.maydell@linaro.org>2010-12-07 15:37:34 +0000
committerPeter Maydell <peter.maydell@linaro.org>2010-12-07 15:37:34 +0000
commitcbcef455a2d29cdd19f4f0a21990cd76c0d03102 (patch)
tree8a0080abccbb4db822e5ce84085dd6355d372513
parent26a5e69aafd0434922316e4185c45c9bddd4b9ba (diff)
downloadqemu-arm-cbcef455a2d29cdd19f4f0a21990cd76c0d03102.tar.gz
softfloat: Add float/double to 16 bit integer conversion functions
The ARM architecture needs float/double to 16 bit integer conversions. (The 32 bit versions aren't sufficient because of the requirement to saturate at 16 bit MAXINT/MININT and to get the exception bits right.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Nathan Froyd <froydnj@codesourcery.com>
-rw-r--r--fpu/softfloat.c136
-rw-r--r--fpu/softfloat.h4
2 files changed, 140 insertions, 0 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 0b8279798c..6f5b05d5fe 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1355,6 +1355,55 @@ int32 float32_to_int32_round_to_zero( float32 a STATUS_PARAM )
/*----------------------------------------------------------------------------
| Returns the result of converting the single-precision floating-point value
+| `a' to the 16-bit two's complement integer format. The conversion is
+| performed according to the IEC/IEEE Standard for Binary Floating-Point
+| Arithmetic, except that the conversion is always rounded toward zero.
+| If `a' is a NaN, the largest positive integer is returned. Otherwise, if
+| the conversion overflows, the largest integer with the same sign as `a' is
+| returned.
+*----------------------------------------------------------------------------*/
+
+int16 float32_to_int16_round_to_zero( float32 a STATUS_PARAM )
+{
+ flag aSign;
+ int16 aExp, shiftCount;
+ bits32 aSig;
+ int32 z;
+
+ aSig = extractFloat32Frac( a );
+ aExp = extractFloat32Exp( a );
+ aSign = extractFloat32Sign( a );
+ shiftCount = aExp - 0x8E;
+ if ( 0 <= shiftCount ) {
+ if ( float32_val(a) != 0xC7000000 ) {
+ float_raise( float_flag_invalid STATUS_VAR);
+ if ( ! aSign || ( ( aExp == 0xFF ) && aSig ) ) {
+ return 0x7FFF;
+ }
+ }
+ return (sbits32) 0xffff8000;
+ }
+ else if ( aExp <= 0x7E ) {
+ if ( aExp | aSig ) {
+ STATUS(float_exception_flags) |= float_flag_inexact;
+ }
+ return 0;
+ }
+ shiftCount -= 0x10;
+ aSig = ( aSig | 0x00800000 )<<8;
+ z = aSig>>( - shiftCount );
+ if ( (bits32) ( aSig<<( shiftCount & 31 ) ) ) {
+ STATUS(float_exception_flags) |= float_flag_inexact;
+ }
+ if ( aSign ) {
+ z = - z;
+ }
+ return z;
+
+}
+
+/*----------------------------------------------------------------------------
+| Returns the result of converting the single-precision floating-point value
| `a' to the 64-bit two's complement integer format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic---which means in particular that the conversion is rounded
@@ -2412,6 +2461,57 @@ int32 float64_to_int32_round_to_zero( float64 a STATUS_PARAM )
/*----------------------------------------------------------------------------
| Returns the result of converting the double-precision floating-point value
+| `a' to the 16-bit two's complement integer format. The conversion is
+| performed according to the IEC/IEEE Standard for Binary Floating-Point
+| Arithmetic, except that the conversion is always rounded toward zero.
+| If `a' is a NaN, the largest positive integer is returned. Otherwise, if
+| the conversion overflows, the largest integer with the same sign as `a' is
+| returned.
+*----------------------------------------------------------------------------*/
+
+int16 float64_to_int16_round_to_zero( float64 a STATUS_PARAM )
+{
+ flag aSign;
+ int16 aExp, shiftCount;
+ bits64 aSig, savedASig;
+ int32 z;
+
+ aSig = extractFloat64Frac( a );
+ aExp = extractFloat64Exp( a );
+ aSign = extractFloat64Sign( a );
+ if ( 0x40E < aExp ) {
+ if ( ( aExp == 0x7FF ) && aSig ) {
+ aSign = 0;
+ }
+ goto invalid;
+ }
+ else if ( aExp < 0x3FF ) {
+ if ( aExp || aSig ) {
+ STATUS(float_exception_flags) |= float_flag_inexact;
+ }
+ return 0;
+ }
+ aSig |= LIT64( 0x0010000000000000 );
+ shiftCount = 0x433 - aExp;
+ savedASig = aSig;
+ aSig >>= shiftCount;
+ z = aSig;
+ if ( aSign ) {
+ z = - z;
+ }
+ if ( ( (int16_t)z < 0 ) ^ aSign ) {
+ invalid:
+ float_raise( float_flag_invalid STATUS_VAR);
+ return aSign ? (sbits32) 0xffff8000 : 0x7FFF;
+ }
+ if ( ( aSig<<shiftCount ) != savedASig ) {
+ STATUS(float_exception_flags) |= float_flag_inexact;
+ }
+ return z;
+}
+
+/*----------------------------------------------------------------------------
+| Returns the result of converting the double-precision floating-point value
| `a' to the 64-bit two's complement integer format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic---which means in particular that the conversion is rounded
@@ -5632,6 +5732,24 @@ unsigned int float32_to_uint32_round_to_zero( float32 a STATUS_PARAM )
return res;
}
+unsigned int float32_to_uint16_round_to_zero( float32 a STATUS_PARAM )
+{
+ int64_t v;
+ unsigned int res;
+
+ v = float32_to_int64_round_to_zero(a STATUS_VAR);
+ if (v < 0) {
+ res = 0;
+ float_raise( float_flag_invalid STATUS_VAR);
+ } else if (v > 0xffff) {
+ res = 0xffff;
+ float_raise( float_flag_invalid STATUS_VAR);
+ } else {
+ res = v;
+ }
+ return res;
+}
+
unsigned int float64_to_uint32( float64 a STATUS_PARAM )
{
int64_t v;
@@ -5668,6 +5786,24 @@ unsigned int float64_to_uint32_round_to_zero( float64 a STATUS_PARAM )
return res;
}
+unsigned int float64_to_uint16_round_to_zero( float64 a STATUS_PARAM )
+{
+ int64_t v;
+ unsigned int res;
+
+ v = float64_to_int64_round_to_zero(a STATUS_VAR);
+ if (v < 0) {
+ res = 0;
+ float_raise( float_flag_invalid STATUS_VAR);
+ } else if (v > 0xffff) {
+ res = 0xffff;
+ float_raise( float_flag_invalid STATUS_VAR);
+ } else {
+ res = v;
+ }
+ return res;
+}
+
/* FIXME: This looks broken. */
uint64_t float64_to_uint64 (float64 a STATUS_PARAM)
{
diff --git a/fpu/softfloat.h b/fpu/softfloat.h
index 2e651e2605..1c1004de97 100644
--- a/fpu/softfloat.h
+++ b/fpu/softfloat.h
@@ -251,6 +251,8 @@ float32 float16_to_float32( bits16, flag STATUS_PARAM );
/*----------------------------------------------------------------------------
| Software IEC/IEEE single-precision conversion routines.
*----------------------------------------------------------------------------*/
+int float32_to_int16_round_to_zero( float32 STATUS_PARAM );
+unsigned int float32_to_uint16_round_to_zero( float32 STATUS_PARAM );
int float32_to_int32( float32 STATUS_PARAM );
int float32_to_int32_round_to_zero( float32 STATUS_PARAM );
unsigned int float32_to_uint32( float32 STATUS_PARAM );
@@ -327,6 +329,8 @@ INLINE int float32_is_any_nan(float32 a)
/*----------------------------------------------------------------------------
| Software IEC/IEEE double-precision conversion routines.
*----------------------------------------------------------------------------*/
+int float64_to_int16_round_to_zero( float64 STATUS_PARAM );
+unsigned int float64_to_uint16_round_to_zero( float64 STATUS_PARAM );
int float64_to_int32( float64 STATUS_PARAM );
int float64_to_int32_round_to_zero( float64 STATUS_PARAM );
unsigned int float64_to_uint32( float64 STATUS_PARAM );