Patchwork [1/2] softfloat: Fix uint64_to_float64

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Submitter Richard Henderson
Date Dec. 11, 2012, 5:21 p.m.
Message ID <1355246472-16743-2-git-send-email-rth@twiddle.net>
Download mbox | patch
Permalink /patch/205274/
State New
Headers show

Comments

Richard Henderson - Dec. 11, 2012, 5:21 p.m.
The interface to normalizeRoundAndPackFloat64 requires that the
high bit be clear.  Perform one shift-right-and-jam if needed.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 fpu/softfloat.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
Peter Maydell - Dec. 11, 2012, 5:34 p.m.
On 11 December 2012 17:21, Richard Henderson <rth@twiddle.net> wrote:
> The interface to normalizeRoundAndPackFloat64 requires that the
> high bit be clear.  Perform one shift-right-and-jam if needed.
>
> Signed-off-by: Richard Henderson <rth@twiddle.net>

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

-- PMM

Patch

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 8413146..0daad0d 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1271,11 +1271,18 @@  float64 int64_to_float64( int64 a STATUS_PARAM )
 
 }
 
-float64 uint64_to_float64( uint64 a STATUS_PARAM )
+float64 uint64_to_float64(uint64 a STATUS_PARAM)
 {
-    if ( a == 0 ) return float64_zero;
-    return normalizeRoundAndPackFloat64( 0, 0x43C, a STATUS_VAR );
+    int exp = 0x43C;
 
+    if (a == 0) {
+        return float64_zero;
+    }
+    if ((int64_t)a < 0) {
+        shift64RightJamming(a, 1, &a);
+        exp += 1;
+    }
+    return normalizeRoundAndPackFloat64(0, exp, a STATUS_VAR);
 }
 
 /*----------------------------------------------------------------------------