softfloat: add int128_to_float128

[mirror_qemu.git] / fpu / softfloat.c

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 57445b36e709b5be30cb483521b21f9cb40ac80f..60b47029450801118e7a05eb4bc02fffe0f6605a 100644 (file)
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -3780,6 +3780,35 @@ bfloat16 int16_to_bfloat16(int16_t a, float_status *status)
     return int64_to_bfloat16_scalbn(a, 0, status);
 }
 
+float128 int128_to_float128(Int128 a, float_status *status)
+{
+    FloatParts128 p = { };
+    int shift;
+
+    if (int128_nz(a)) {
+        p.cls = float_class_normal;
+        if (!int128_nonneg(a)) {
+            p.sign = true;
+            a = int128_neg(a);
+        }
+
+        shift = clz64(int128_gethi(a));
+        if (shift == 64) {
+            shift += clz64(int128_getlo(a));
+        }
+
+        p.exp = 127 - shift;
+        a = int128_lshift(a, shift);
+
+        p.frac_hi = int128_gethi(a);
+        p.frac_lo = int128_getlo(a);
+    } else {
+        p.cls = float_class_zero;
+    }
+
+    return float128_round_pack_canonical(&p, status);
+}
+
 float128 int64_to_float128(int64_t a, float_status *status)
 {
     FloatParts128 p;