[RFC PATCH 2/6] softfloat: add int128_to_float* conversion methods

[matheus . ferst]

From: Matheus Ferst <matheus.ferst@eldorado.org.br>

Based on parts_sint_to_float, implements parts_sint_to_float2 that
receives a 128-bit signed integer via int64_t and uint64_t arguments.

Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
---
 fpu/softfloat-parts.c.inc | 37 +++++++++++++++++++++++++++++++++++++
 fpu/softfloat.c           | 30 ++++++++++++++++++++++++++++++
 include/fpu/softfloat.h   |  3 +++
 3 files changed, 70 insertions(+)

diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index 0bbecf835f..5f7f107a0d 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -1196,6 +1196,43 @@ static void partsN(sint_to_float)(FloatPartsN *p, 
int64_t a,
     p->frac_hi = f << shift;
 }
 
+static void partsN(sint_to_float2)(FloatPartsN *p, int64_t hi, uint64_t lo,
+                                   int scale, float_status *status)
+{
+    uint64_t f = hi;
+    int shift;
+
+    if (hi == 0) {
+        parts_uint_to_float(p, lo, scale, status);
+    } else {
+        memset(p, 0, sizeof(*p));
+        p->cls = float_class_normal;
+        if (hi < 0) {
+            lo = -lo;
+            f = ~f + !lo;
+            p->sign = true;
+        }
+        if (f != 0) {
+            shift = clz64(f);
+        } else {
+            shift = 64 + clz64(lo);
+        }
+        scale = MIN(MAX(scale, -0x10000), 0x10000);
+
+        p->exp = 127 - shift + scale;
+
+        if (shift >= 64) {
+            f = lo;
+            lo = 0;
+            shift -= 64;
+        }
+        p->frac_hi = shl_double(f, lo, shift);
+        if (N > 64) {
+            p->frac_lo = shl_double(lo, 0, shift);
+        }
+    }
+}
+
 /*
  * Unsigned Integer to float conversions
  *
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 980ddfe5a1..ac3d6f5ab0 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -858,6 +858,14 @@ static void parts128_sint_to_float(FloatParts128 *p, 
int64_t a,
 #define parts_sint_to_float(P, I, Z, S) \
     PARTS_GENERIC_64_128(sint_to_float, P)(P, I, Z, S)
 
+static void parts64_sint_to_float2(FloatParts64 *p, int64_t hi, uint64_t lo,
+                                   int scale, float_status *s);
+static void parts128_sint_to_float2(FloatParts128 *p, int64_t hi, uint64_t lo,
+                                    int scale, float_status *s);
+
+#define parts_sint_to_float2(P, H, L, Z, S) \
+    PARTS_GENERIC_64_128(sint_to_float2, P)(P, H, L, Z, S)
+
 static void parts64_uint_to_float(FloatParts64 *p, uint64_t a,
                                   int scale, float_status *s);
 static void parts128_uint_to_float(FloatParts128 *p, uint64_t a,
@@ -3715,6 +3723,15 @@ float32 int16_to_float32(int16_t a, float_status *status)
     return int64_to_float32_scalbn(a, 0, status);
 }
 
+float64 int128_to_float64_scalbn(int64_t hi, uint64_t lo, int scale,
+                                 float_status *status)
+{
+    FloatParts64 p;
+
+    parts_sint_to_float2(&p, hi, lo, scale, status);
+    return float64_round_pack_canonical(&p, status);
+}
+
 float64 int64_to_float64_scalbn(int64_t a, int scale, float_status *status)
 {
     FloatParts64 p;
@@ -3740,6 +3757,11 @@ float64 int16_to_float64_scalbn(int16_t a, int scale, 
float_status *status)
     return int64_to_float64_scalbn(a, scale, status);
 }
 
+float64 int128_to_float64(int64_t hi, uint64_t lo, float_status *status)
+{
+    return int128_to_float64_scalbn(hi, lo, 0, status);
+}
+
 float64 int64_to_float64(int64_t a, float_status *status)
 {
     return int64_to_float64_scalbn(a, 0, status);
@@ -3788,6 +3810,14 @@ bfloat16 int16_to_bfloat16(int16_t a, float_status 
*status)
     return int64_to_bfloat16_scalbn(a, 0, status);
 }
 
+float128 int128_to_float128(int64_t hi, uint64_t lo, float_status *status)
+{
+    FloatParts128 p;
+
+    parts_sint_to_float2(&p, hi, lo, 0, status);
+    return float128_round_pack_canonical(&p, status);
+}
+
 float128 int64_to_float128(int64_t a, float_status *status)
 {
     FloatParts128 p;
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 2ef4fec3d0..5a2165a187 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -166,6 +166,7 @@ float32 uint64_to_float32(uint64_t, float_status *status);
 float64 int16_to_float64_scalbn(int16_t, int, float_status *status);
 float64 int32_to_float64_scalbn(int32_t, int, float_status *status);
 float64 int64_to_float64_scalbn(int64_t, int, float_status *status);
+float64 int128_to_float64_scalbn(int64_t, uint64_t, int, float_status *status);
 float64 uint16_to_float64_scalbn(uint16_t, int, float_status *status);
 float64 uint32_to_float64_scalbn(uint32_t, int, float_status *status);
 float64 uint64_to_float64_scalbn(uint64_t, int, float_status *status);
@@ -175,6 +176,7 @@ float64 uint128_to_float64_scalbn(uint64_t, uint64_t, int,
 float64 int16_to_float64(int16_t, float_status *status);
 float64 int32_to_float64(int32_t, float_status *status);
 float64 int64_to_float64(int64_t, float_status *status);
+float64 int128_to_float64(int64_t, uint64_t, float_status *status);
 float64 uint16_to_float64(uint16_t, float_status *status);
 float64 uint32_to_float64(uint32_t, float_status *status);
 float64 uint64_to_float64(uint64_t, float_status *status);
@@ -185,6 +187,7 @@ floatx80 int64_to_floatx80(int64_t, float_status *status);
 
 float128 int32_to_float128(int32_t, float_status *status);
 float128 int64_to_float128(int64_t, float_status *status);
+float128 int128_to_float128(int64_t, uint64_t, float_status *status);
 float128 uint64_to_float128(uint64_t, float_status *status);
 float128 uint128_to_float128(uint64_t, uint64_t, float_status *status);
 
-- 
2.25.1