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[V5,02/22] softfloat: Add float32_to_uint64()

Message ID 1388701295-29855-3-git-send-email-tommusta@gmail.com
State New
Headers show

Commit Message

Tom Musta Jan. 2, 2014, 10:21 p.m. UTC 
This patch adds the float32_to_uint64() routine, which converts a
32-bit floating point number to an unsigned 64 bit number.

This contribution can be licensed under either the softfloat-2a or -2b
license.

Signed-off-by: Tom Musta <tommusta@gmail.com>
---
V2: Reduced patch to just this single routine per feedback from Peter
Maydell.

V4: Now passing sign to roundAndPackUint64()

V5: Proper handling of small negatives and negative NaNs.

 fpu/softfloat.c         |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 include/fpu/softfloat.h |    1 +
 2 files changed, 47 insertions(+), 0 deletions(-)

Comments

Peter Maydell Jan. 6, 2014, 12:54 p.m. UTC | #1 
On 2 January 2014 22:21, Tom Musta <tommusta@gmail.com> wrote:
> This patch adds the float32_to_uint64() routine, which converts a
> 32-bit floating point number to an unsigned 64 bit number.
>
> This contribution can be licensed under either the softfloat-2a or -2b
> license.
>
> Signed-off-by: Tom Musta <tommusta@gmail.com>>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
diff mbox

Patch

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 05e2877..9f42a5b 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1558,6 +1558,52 @@  int64 float32_to_int64( float32 a STATUS_PARAM )
 
 /*----------------------------------------------------------------------------
 | Returns the result of converting the single-precision floating-point value
+| `a' to the 64-bit unsigned 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
+| according to the current rounding mode.  If `a' is a NaN, the largest
+| unsigned integer is returned.  Otherwise, if the conversion overflows, the
+| largest unsigned integer is returned.  If the 'a' is negative, the result
+| is rounded and zero is returned; values that do not round to zero will
+| raise the inexact exception flag.
+*----------------------------------------------------------------------------*/
+
+uint64 float32_to_uint64(float32 a STATUS_PARAM)
+{
+    flag aSign;
+    int_fast16_t aExp, shiftCount;
+    uint32_t aSig;
+    uint64_t aSig64, aSigExtra;
+    a = float32_squash_input_denormal(a STATUS_VAR);
+
+    aSig = extractFloat32Frac(a);
+    aExp = extractFloat32Exp(a);
+    aSign = extractFloat32Sign(a);
+    if ((aSign) && (aExp > 126)) {
+        float_raise(float_flag_invalid STATUS_VAR);
+        if (float32_is_any_nan(a)) {
+            return (int64_t)LIT64(0xFFFFFFFFFFFFFFFF);
+        } else {
+            return 0;
+        }
+    }
+    shiftCount = 0xBE - aExp;
+    if (aExp) {
+        aSig |= 0x00800000;
+    }
+    if (shiftCount < 0) {
+        float_raise(float_flag_invalid STATUS_VAR);
+        return (int64_t)LIT64(0xFFFFFFFFFFFFFFFF);
+    }
+
+    aSig64 = aSig;
+    aSig64 <<= 40;
+    shift64ExtraRightJamming(aSig64, 0, shiftCount, &aSig64, &aSigExtra);
+    return roundAndPackUint64(aSign, aSig64, aSigExtra STATUS_VAR);
+}
+
+/*----------------------------------------------------------------------------
+| 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, except that the conversion is always rounded toward zero.  If
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 2365274..080b36d 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -272,6 +272,7 @@  int32 float32_to_int32_round_to_zero( float32 STATUS_PARAM );
 uint32 float32_to_uint32( float32 STATUS_PARAM );
 uint32 float32_to_uint32_round_to_zero( float32 STATUS_PARAM );
 int64 float32_to_int64( float32 STATUS_PARAM );
+uint64 float32_to_uint64(float32 STATUS_PARAM);
 int64 float32_to_int64_round_to_zero( float32 STATUS_PARAM );
 float64 float32_to_float64( float32 STATUS_PARAM );
 floatx80 float32_to_floatx80( float32 STATUS_PARAM );