[RFC,v1,2/2] softfloat: Add float128_to_uint32_round_to_zero()

Commit Message

Bharata B Rao Feb. 8, 2017, 12:44 a.m. UTC

On Tue, Feb 07, 2017 at 02:10:04PM -0800, Richard Henderson wrote:
> On 02/07/2017 12:04 AM, Bharata B Rao wrote:
> > +    int64_t v;
> > +    uint32_t res;
> > +    int old_exc_flags = get_float_exception_flags(status);
> > +
> > +    v = float128_to_uint64_round_to_zero(a, status);
> > +    if (v > 0xffffffff) {
> 
> v should be uint64_t.

Right, here is the updated patch...

Peter/David - If you want both the patches to be posted afresh, let me know.
(These patches apply on David's ppc-for-2.9 branch)

From 24afd78beb5f5742f9da76cf5330ea465697be7b Mon Sep 17 00:00:00 2001
From: Bharata B Rao <[e-mail]>
Date: Mon, 30 Jan 2017 15:23:04 +0530
Subject: [PATCH v2 2/2] softfloat: Add float128_to_uint32_round_to_zero()

float128_to_uint32_round_to_zero() is needed by xscvqpuwz instruction
of PowerPC ISA 3.0.

Signed-off-by: Bharata B Rao <[e-mail]>
Reviewed-by: Peter Maydell <[e-mail]>
---
 fpu/softfloat.c         | 28 ++++++++++++++++++++++++++++
 include/fpu/softfloat.h |  1 +
 2 files changed, 29 insertions(+)

Patch

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 4a4b50b..c2f0de0 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -6169,6 +6169,34 @@  uint64_t float128_to_uint64_round_to_zero(float128 a, float_status *status)
 
 /*----------------------------------------------------------------------------
 | Returns the result of converting the quadruple-precision floating-point
+| value `a' to the 32-bit unsigned integer format.  The conversion
+| is performed according to the IEC/IEEE Standard for Binary Floating-Point
+| Arithmetic except that the conversion is always rounded toward zero.
+| If `a' is a NaN, the largest positive integer is returned.  Otherwise,
+| if the conversion overflows, the largest unsigned integer is returned.
+| If 'a' is negative, the value is rounded and zero is returned; negative
+| values that do not round to zero will raise the inexact exception.
+*----------------------------------------------------------------------------*/
+
+uint32_t float128_to_uint32_round_to_zero(float128 a, float_status *status)
+{
+    uint64_t v;
+    uint32_t res;
+    int old_exc_flags = get_float_exception_flags(status);
+
+    v = float128_to_uint64_round_to_zero(a, status);
+    if (v > 0xffffffff) {
+        res = 0xffffffff;
+    } else {
+        return v;
+    }
+    set_float_exception_flags(old_exc_flags, status);
+    float_raise(float_flag_invalid, status);
+    return res;
+}
+
+/*----------------------------------------------------------------------------
+| Returns the result of converting the quadruple-precision floating-point
 | value `a' to the single-precision floating-point format.  The conversion
 | is performed according to the IEC/IEEE Standard for Binary Floating-Point
 | Arithmetic.
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 4e99253..9eb5a6b 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -714,6 +714,7 @@  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_uint64_round_to_zero(float128, float_status *status);
+uint32_t float128_to_uint32_round_to_zero(float128, float_status *status);
 float32 float128_to_float32(float128, float_status *status);
 float64 float128_to_float64(float128, float_status *status);
 floatx80 float128_to_floatx80(float128, float_status *status);