[PULL 6/7] softfloat: Define misc operations for bfloat16

[Richard Henderson]

From: LIU Zhiwei <zhiwei_liu@c-sky.com>

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200813071421.2509-4-zhiwei_liu@c-sky.com>
[rth: Fix merge conflict with NO_SIGNALING_NANS; use bool for predicates.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/fpu/softfloat.h        | 48 ++++++++++++++++++++++++++++++++++
 fpu/softfloat-specialize.c.inc | 38 +++++++++++++++++++++++++++
 2 files changed, 86 insertions(+)

diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 95f0789a92..1233f98014 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -423,9 +423,57 @@ bfloat16 bfloat16_sqrt(bfloat16, float_status *status);
 FloatRelation bfloat16_compare(bfloat16, bfloat16, float_status *status);
 FloatRelation bfloat16_compare_quiet(bfloat16, bfloat16, float_status *status);
 
+bool bfloat16_is_quiet_nan(bfloat16, float_status *status);
+bool bfloat16_is_signaling_nan(bfloat16, float_status *status);
 bfloat16 bfloat16_silence_nan(bfloat16, float_status *status);
 bfloat16 bfloat16_default_nan(float_status *status);
 
+static inline bool bfloat16_is_any_nan(bfloat16 a)
+{
+    return ((a & ~0x8000) > 0x7F80);
+}
+
+static inline bool bfloat16_is_neg(bfloat16 a)
+{
+    return a >> 15;
+}
+
+static inline bool bfloat16_is_infinity(bfloat16 a)
+{
+    return (a & 0x7fff) == 0x7F80;
+}
+
+static inline bool bfloat16_is_zero(bfloat16 a)
+{
+    return (a & 0x7fff) == 0;
+}
+
+static inline bool bfloat16_is_zero_or_denormal(bfloat16 a)
+{
+    return (a & 0x7F80) == 0;
+}
+
+static inline bool bfloat16_is_normal(bfloat16 a)
+{
+    return (((a >> 7) + 1) & 0xff) >= 2;
+}
+
+static inline bfloat16 bfloat16_abs(bfloat16 a)
+{
+    /* Note that abs does *not* handle NaN specially, nor does
+     * it flush denormal inputs to zero.
+     */
+    return a & 0x7fff;
+}
+
+static inline bfloat16 bfloat16_chs(bfloat16 a)
+{
+    /* Note that chs does *not* handle NaN specially, nor does
+     * it flush denormal inputs to zero.
+     */
+    return a ^ 0x8000;
+}
+
 static inline bfloat16 bfloat16_set_sign(bfloat16 a, int sign)
 {
     return (a & 0x7fff) | (sign << 15);
diff --git a/fpu/softfloat-specialize.c.inc b/fpu/softfloat-specialize.c.inc
index dc4ea33c09..c2f87addb2 100644
--- a/fpu/softfloat-specialize.c.inc
+++ b/fpu/softfloat-specialize.c.inc
@@ -265,6 +265,25 @@ bool float16_is_quiet_nan(float16 a_, float_status *status)
     }
 }
 
+/*----------------------------------------------------------------------------
+| Returns 1 if the bfloat16 value `a' is a quiet
+| NaN; otherwise returns 0.
+*----------------------------------------------------------------------------*/
+
+bool bfloat16_is_quiet_nan(bfloat16 a_, float_status *status)
+{
+    if (no_signaling_nans(status)) {
+        return bfloat16_is_any_nan(a_);
+    } else {
+        uint16_t a = a_;
+        if (snan_bit_is_one(status)) {
+            return (((a >> 6) & 0x1FF) == 0x1FE) && (a & 0x3F);
+        } else {
+            return ((a >> 6) & 0x1FF) == 0x1FF;
+        }
+    }
+}
+
 /*----------------------------------------------------------------------------
 | Returns 1 if the half-precision floating-point value `a' is a signaling
 | NaN; otherwise returns 0.
@@ -284,6 +303,25 @@ bool float16_is_signaling_nan(float16 a_, float_status 
*status)
     }
 }
 
+/*----------------------------------------------------------------------------
+| Returns 1 if the bfloat16 value `a' is a signaling
+| NaN; otherwise returns 0.
+*----------------------------------------------------------------------------*/
+
+bool bfloat16_is_signaling_nan(bfloat16 a_, float_status *status)
+{
+    if (no_signaling_nans(status)) {
+        return 0;
+    } else {
+        uint16_t a = a_;
+        if (snan_bit_is_one(status)) {
+            return ((a >> 6) & 0x1FF) == 0x1FF;
+        } else {
+            return (((a >> 6) & 0x1FF) == 0x1FE) && (a & 0x3F);
+        }
+    }
+}
+
 /*----------------------------------------------------------------------------
 | Returns 1 if the single-precision floating-point value `a' is a quiet
 | NaN; otherwise returns 0.
-- 
2.25.1