[RFC PATCH 3/6] softfloat: add float*_to_uint128 conversion methods

[matheus . ferst]

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

Implements parts_float_to_uint2 based on parts_float_to_uint logic. The
new methods return the lower part of the result through the "lo"
pointer.

Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
---
 fpu/softfloat-parts.c.inc | 71 +++++++++++++++++++++++++++++++++++++++
 fpu/softfloat.c           | 51 ++++++++++++++++++++++++++++
 include/fpu/softfloat.h   |  8 +++++
 3 files changed, 130 insertions(+)

diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
index 5f7f107a0d..2767aeac03 100644
--- a/fpu/softfloat-parts.c.inc
+++ b/fpu/softfloat-parts.c.inc
@@ -1164,6 +1164,77 @@ static uint64_t partsN(float_to_uint)(FloatPartsN *p, 
FloatRoundMode rmode,
     return r;
 }
 
+static uint64_t partsN(float_to_uint2)(FloatPartsN *p, FloatRoundMode rmode,
+                                       int scale, float_status *s, uint64_t 
*lo)
+{
+    int flags = 0;
+    uint64_t hi;
+
+    switch (p->cls) {
+    case float_class_snan:
+        flags |= float_flag_invalid_snan;
+        /* fall through */
+    case float_class_qnan:
+        flags |= float_flag_invalid;
+        hi = UINT64_MAX;
+        *lo = UINT64_MAX;
+        break;
+
+    case float_class_inf:
+        flags = float_flag_invalid | float_flag_invalid_cvti;
+        if (p->sign) {
+            hi = 0;
+            *lo = 0;
+        } else {
+            hi = UINT64_MAX;
+            *lo = UINT64_MAX;
+        }
+        break;
+
+    case float_class_zero:
+        *lo = 0;
+        return 0;
+
+    case float_class_normal:
+        if (parts_round_to_int_normal(p, rmode, scale, N - 2)) {
+            flags = float_flag_inexact;
+            if (p->cls == float_class_zero) {
+                hi = 0;
+                *lo = 0;
+                break;
+            }
+        }
+
+        if (p->sign) {
+            flags = float_flag_invalid | float_flag_invalid_cvti;
+            hi = 0;
+            *lo = 0;
+        } else if (p->exp <= DECOMPOSED_BINARY_POINT) {
+            hi = 0;
+            *lo = p->frac_hi >> (DECOMPOSED_BINARY_POINT - p->exp);
+        } else if (p->exp <= 127) {
+            int shift = 127 - p->exp;
+            hi = shr_double(0, p->frac_hi, shift);
+            if (N > 64) {
+                *lo = shr_double(p->frac_hi, p->frac_lo, shift);
+            } else {
+                *lo = shr_double(p->frac_hi, 0, shift);
+            }
+        } else {
+            flags = float_flag_invalid | float_flag_invalid_cvti;
+            hi = UINT64_MAX;
+            *lo = UINT64_MAX;
+        }
+        break;
+
+    default:
+        g_assert_not_reached();
+    }
+
+    float_raise(flags, s);
+    return hi;
+}
+
 /*
  * Integer to float conversions
  *
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index ac3d6f5ab0..fe4320060c 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -850,6 +850,16 @@ static uint64_t parts128_float_to_uint(FloatParts128 *p, 
FloatRoundMode rmode,
 #define parts_float_to_uint(P, R, Z, M, S) \
     PARTS_GENERIC_64_128(float_to_uint, P)(P, R, Z, M, S)
 
+static uint64_t parts64_float_to_uint2(FloatParts64 *p, FloatRoundMode rmode,
+                                       int scale, float_status *s,
+                                       uint64_t *lo);
+static uint64_t parts128_float_to_uint2(FloatParts128 *p, FloatRoundMode rmode,
+                                        int scale, float_status *s,
+                                        uint64_t *lo);
+
+#define parts_float_to_uint2(P, R, Z, S, H) \
+    PARTS_GENERIC_64_128(float_to_uint2, P)(P, R, Z, S, H)
+
 static void parts64_sint_to_float(FloatParts64 *p, int64_t a,
                                   int scale, float_status *s);
 static void parts128_sint_to_float(FloatParts128 *p, int64_t a,
@@ -3451,6 +3461,15 @@ uint64_t float64_to_uint64_scalbn(float64 a, 
FloatRoundMode rmode, int scale,
     return parts_float_to_uint(&p, rmode, scale, UINT64_MAX, s);
 }
 
+uint64_t float64_to_uint128_scalbn(float64 a, FloatRoundMode rmode, int scale,
+                                   float_status *s, uint64_t *lo)
+{
+    FloatParts64 p;
+
+    float64_unpack_canonical(&p, a, s);
+    return parts_float_to_uint2(&p, rmode, scale, s, lo);
+}
+
 uint16_t bfloat16_to_uint16_scalbn(bfloat16 a, FloatRoundMode rmode,
                                    int scale, float_status *s)
 {
@@ -3496,6 +3515,16 @@ static uint64_t float128_to_uint64_scalbn(float128 a, 
FloatRoundMode rmode,
     return parts_float_to_uint(&p, rmode, scale, UINT64_MAX, s);
 }
 
+static uint64_t float128_to_uint128_scalbn(float128 a, FloatRoundMode rmode,
+                                           int scale, float_status *s,
+                                           uint64_t *lo)
+{
+    FloatParts128 p;
+
+    float128_unpack_canonical(&p, a, s);
+    return parts_float_to_uint2(&p, rmode, scale, s, lo);
+}
+
 uint8_t float16_to_uint8(float16 a, float_status *s)
 {
     return float16_to_uint8_scalbn(a, s->float_rounding_mode, 0, s);
@@ -3546,6 +3575,11 @@ uint64_t float64_to_uint64(float64 a, float_status *s)
     return float64_to_uint64_scalbn(a, s->float_rounding_mode, 0, s);
 }
 
+uint64_t float64_to_uint128(float64 a, float_status *s, uint64_t *lo)
+{
+    return float64_to_uint128_scalbn(a, s->float_rounding_mode, 0, s, lo);
+}
+
 uint32_t float128_to_uint32(float128 a, float_status *s)
 {
     return float128_to_uint32_scalbn(a, s->float_rounding_mode, 0, s);
@@ -3556,6 +3590,11 @@ uint64_t float128_to_uint64(float128 a, float_status *s)
     return float128_to_uint64_scalbn(a, s->float_rounding_mode, 0, s);
 }
 
+uint64_t float128_to_uint128(float128 a, float_status *s, uint64_t *lo)
+{
+    return float128_to_uint128_scalbn(a, s->float_rounding_mode, 0, s, lo);
+}
+
 uint16_t float16_to_uint16_round_to_zero(float16 a, float_status *s)
 {
     return float16_to_uint16_scalbn(a, float_round_to_zero, 0, s);
@@ -3601,6 +3640,12 @@ uint64_t float64_to_uint64_round_to_zero(float64 a, 
float_status *s)
     return float64_to_uint64_scalbn(a, float_round_to_zero, 0, s);
 }
 
+uint64_t float64_to_uint128_round_to_zero(float64 a, float_status *s,
+                                          uint64_t *lo)
+{
+    return float64_to_uint128_scalbn(a, float_round_to_zero, 0, s, lo);
+}
+
 uint32_t float128_to_uint32_round_to_zero(float128 a, float_status *s)
 {
     return float128_to_uint32_scalbn(a, float_round_to_zero, 0, s);
@@ -3611,6 +3656,12 @@ uint64_t float128_to_uint64_round_to_zero(float128 a, 
float_status *s)
     return float128_to_uint64_scalbn(a, float_round_to_zero, 0, s);
 }
 
+uint64_t float128_to_uint128_round_to_zero(float128 a, float_status *s,
+                                           uint64_t *lo)
+{
+    return float128_to_uint128_scalbn(a, float_round_to_zero, 0, s, lo);
+}
+
 uint16_t bfloat16_to_uint16(bfloat16 a, float_status *s)
 {
     return bfloat16_to_uint16_scalbn(a, s->float_rounding_mode, 0, s);
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 5a2165a187..01d8edbc73 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -758,14 +758,19 @@ int64_t float64_to_int64_round_to_zero(float64, 
float_status *status);
 uint16_t float64_to_uint16_scalbn(float64, FloatRoundMode, int, float_status 
*);
 uint32_t float64_to_uint32_scalbn(float64, FloatRoundMode, int, float_status 
*);
 uint64_t float64_to_uint64_scalbn(float64, FloatRoundMode, int, float_status 
*);
+uint64_t float64_to_uint128_scalbn(float64, FloatRoundMode, int, float_status 
*,
+                                   uint64_t *);
 
 uint16_t float64_to_uint16(float64, float_status *status);
 uint32_t float64_to_uint32(float64, float_status *status);
 uint64_t float64_to_uint64(float64, float_status *status);
+uint64_t float64_to_uint128(float64, float_status *status, uint64_t *lo);
 
 uint16_t float64_to_uint16_round_to_zero(float64, float_status *status);
 uint32_t float64_to_uint32_round_to_zero(float64, float_status *status);
 uint64_t float64_to_uint64_round_to_zero(float64, float_status *status);
+uint64_t float64_to_uint128_round_to_zero(float64, float_status *status,
+                                          uint64_t *lo);
 
 float32 float64_to_float32(float64, float_status *status);
 floatx80 float64_to_floatx80(float64, float_status *status);
@@ -1210,7 +1215,10 @@ int32_t float128_to_int32_round_to_zero(float128, 
float_status *status);
 int64_t float128_to_int64(float128, float_status *status);
 int64_t float128_to_int64_round_to_zero(float128, float_status *status);
 uint64_t float128_to_uint64(float128, float_status *status);
+uint64_t float128_to_uint128(float128, float_status *status, uint64_t *lo);
 uint64_t float128_to_uint64_round_to_zero(float128, float_status *status);
+uint64_t float128_to_uint128_round_to_zero(float128, float_status *status,
+                                           uint64_t *lo);
 uint32_t float128_to_uint32(float128, float_status *status);
 uint32_t float128_to_uint32_round_to_zero(float128, float_status *status);
 float32 float128_to_float32(float128, float_status *status);
-- 
2.25.1