[RFC,8/8] fpu/softfloat: define misc operation for bfloat16

Commit Message

LIU Zhiwei July 12, 2020, 11:45 p.m. UTC

Signed-off-by: LIU Zhiwei <[e-mail]>
---
 fpu/softfloat-specialize.inc.c | 38 +++++++++++++++++++++++++++++++
 include/fpu/softfloat.h        | 41 ++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

Comments

Richard Henderson July 13, 2020, 7:37 p.m. UTC | #1

On 7/12/20 4:45 PM, LIU Zhiwei wrote:
> Signed-off-by: LIU Zhiwei <[e-mail]>
> ---
>  fpu/softfloat-specialize.inc.c | 38 +++++++++++++++++++++++++++++++
>  include/fpu/softfloat.h        | 41 ++++++++++++++++++++++++++++++++++
>  2 files changed, 79 insertions(+)

Reviewed-by: Richard Henderson <[e-mail]>

s/brain floating-point/bfloat16/.


r~

Patch

diff --git a/fpu/softfloat-specialize.inc.c b/fpu/softfloat-specialize.inc.c
index 6b778a7830..ff17f11f0c 100644
--- a/fpu/softfloat-specialize.inc.c
+++ b/fpu/softfloat-specialize.inc.c
@@ -259,6 +259,25 @@  bool float16_is_quiet_nan(float16 a_, float_status *status)
 #endif
 }
 
+/*----------------------------------------------------------------------------
+| Returns 1 if the brain floating point value `a' is a quiet
+| NaN; otherwise returns 0.
+*----------------------------------------------------------------------------*/
+
+int bfloat16_is_quiet_nan(bfloat16 a_, float_status *status)
+{
+#ifdef NO_SIGNALING_NANS
+    return bfloat16_is_any_nan(a_);
+#else
+    uint16_t a = bfloat16_val(a_);
+    if (snan_bit_is_one(status)) {
+        return (((a >> 6) & 0x1FF) == 0x1FE) && (a & 0x3F);
+    } else {
+        return ((a >> 6) & 0x1FF) == 0x1FF;
+    }
+#endif
+}
+
 /*----------------------------------------------------------------------------
 | Returns 1 if the half-precision floating-point value `a' is a signaling
 | NaN; otherwise returns 0.
@@ -278,6 +297,25 @@  bool float16_is_signaling_nan(float16 a_, float_status *status)
 #endif
 }
 
+/*----------------------------------------------------------------------------
+| Returns 1 if the brain floating point value `a' is a signaling
+| NaN; otherwise returns 0.
+*----------------------------------------------------------------------------*/
+
+int bfloat16_is_signaling_nan(bfloat16 a_, float_status *status)
+{
+#ifdef NO_SIGNALING_NANS
+    return 0;
+#else
+    uint16_t a = bfloat16_val(a_);
+    if (snan_bit_is_one(status)) {
+        return ((a >> 6) & 0x1FF) == 0x1FF;
+    } else {
+        return (((a >> 6) & 0x1FF) == 0x1FE) && (a & 0x3F);
+    }
+#endif
+}
+
 /*----------------------------------------------------------------------------
 | Returns 1 if the single-precision floating-point value `a' is a quiet
 | NaN; otherwise returns 0.
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 6590850253..d2c3f5fbe0 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -372,6 +372,47 @@  static inline float16 float16_set_sign(float16 a, int sign)
 #define float16_three make_float16(0x4200)
 #define float16_infinity make_float16(0x7c00)
 
+static inline int bfloat16_is_any_nan(bfloat16 a)
+{
+    return ((bfloat16_val(a) & ~0x8000) > 0x7F80);
+}
+
+static inline int bfloat16_is_neg(bfloat16 a)
+{
+    return bfloat16_val(a) >> 15;
+}
+
+static inline int bfloat16_is_infinity(bfloat16 a)
+{
+    return (bfloat16_val(a) & 0x7fff) == 0x7F80;
+}
+
+static inline int bfloat16_is_zero(bfloat16 a)
+{
+    return (bfloat16_val(a) & 0x7fff) == 0;
+}
+
+static inline int bfloat16_is_zero_or_denormal(bfloat16 a)
+{
+    return (bfloat16_val(a) & 0x7F80) == 0;
+}
+
+static inline bfloat16 bfloat16_abs(bfloat16 a)
+{
+    /* Note that abs does *not* handle NaN specially, nor does
+     * it flush denormal inputs to zero.
+     */
+    return make_bfloat16(bfloat16_val(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 make_bfloat16(bfloat16_val(a) ^ 0x8000);
+}
+
 static inline bfloat16 bfloat16_set_sign(bfloat16 a, int sign)
 {
     return make_bfloat16((bfloat16_val(a) & 0x7fff) | (sign << 15));