[Qemu-devel] [RFC PATCH v1 0/2] softfloat: float128 to uint64 and uint32

[Qemu-devel] [RFC PATCH v1 0/2] softfloat: float128 to uint64 and uint32

[Bharata B Rao]

This series introduces two conversion routines: 
float128_to_uint64_round_to_zero() and float128_to_uint32_round_to_zero().

float128_to_uint64_round_to_zero() uses the newly added
float128_to_uint64() whose implementation is based on float64_to_uint64().

float128_to_uint32_round_to_zero() uses float128_to_uint64_round_to_zero().

Changes in v1:
--------------
- Reimplemented float128_to_uint64() based on float64_to_uint64().
- Added float128_to_uint32_round_to_zero().

v0: https://www.mail-archive.com/qemu-devel@nongnu.org/msg426756.html

Bharata B Rao (2):
  softfloat: Add float128_to_uint64_round_to_zero()
  softfloat: Add float128_to_uint32_round_to_zero()

 fpu/softfloat.c         | 87 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/fpu/softfloat.h |  3 ++
 2 files changed, 90 insertions(+)

-- 
2.7.4

[Qemu-devel] [RFC PATCH v1 1/2] softfloat: Add float128_to_uint64_round_to_zero()

[Bharata B Rao]

Implement float128_to_uint64() and use that to implement
float128_to_uint64_round_to_zero()

This is required by xscvqpudz instruction of PowerPC ISA 3.0.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 fpu/softfloat.c         | 59 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/fpu/softfloat.h |  2 ++
 2 files changed, 61 insertions(+)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index c295f31..4a4b50b 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -6109,6 +6109,65 @@ int64_t float128_to_int64_round_to_zero(float128 a, float_status *status)
 }
 
 /*----------------------------------------------------------------------------
+| Returns the result of converting the quadruple-precision floating-point value
+| `a' to the 64-bit unsigned integer format.  The conversion is
+| performed according to the IEC/IEEE Standard for Binary Floating-Point
+| Arithmetic---which means in particular that the conversion is rounded
+| according to the current rounding mode.  If `a' is a NaN, the largest
+| positive integer is returned.  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.
+*----------------------------------------------------------------------------*/
+
+uint64_t float128_to_uint64(float128 a, float_status *status)
+{
+    flag aSign;
+    int aExp;
+    int shiftCount;
+    uint64_t aSig0, aSig1;
+
+    aSig0 = extractFloat128Frac0(a);
+    aSig1 = extractFloat128Frac1(a);
+    aExp = extractFloat128Exp(a);
+    aSign = extractFloat128Sign(a);
+    if (aSign && (aExp > 0x3FFE)) {
+        float_raise(float_flag_invalid, status);
+        if (float128_is_any_nan(a)) {
+            return LIT64(0xFFFFFFFFFFFFFFFF);
+        } else {
+            return 0;
+        }
+    }
+    if (aExp) {
+        aSig0 |= LIT64(0x0001000000000000);
+    }
+    shiftCount = 0x402F - aExp;
+    if (shiftCount <= 0) {
+        if (0x403E < aExp) {
+            float_raise(float_flag_invalid, status);
+            return LIT64(0xFFFFFFFFFFFFFFFF);
+        }
+        shortShift128Left(aSig0, aSig1, -shiftCount, &aSig0, &aSig1);
+    } else {
+        shift64ExtraRightJamming(aSig0, aSig1, shiftCount, &aSig0, &aSig1);
+    }
+    return roundAndPackUint64(aSign, aSig0, aSig1, status);
+}
+
+uint64_t float128_to_uint64_round_to_zero(float128 a, float_status *status)
+{
+    uint64_t v;
+    signed char current_rounding_mode = status->float_rounding_mode;
+
+    set_float_rounding_mode(float_round_to_zero, status);
+    v = float128_to_uint64(a, status);
+    set_float_rounding_mode(current_rounding_mode, status);
+
+    return v;
+}
+
+/*----------------------------------------------------------------------------
 | 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
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 842ec6b..4e99253 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -712,6 +712,8 @@ int32_t float128_to_int32(float128, float_status *status);
 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_uint64_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);
-- 
2.7.4

[Qemu-devel] [RFC PATCH v1 2/2] softfloat: Add float128_to_uint32_round_to_zero()

[Bharata B Rao]

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

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 fpu/softfloat.c         | 28 ++++++++++++++++++++++++++++
 include/fpu/softfloat.h |  1 +
 2 files changed, 29 insertions(+)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 4a4b50b..ed76629 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)
+{
+    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) {
+        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);
-- 
2.7.4

Re: [Qemu-devel] [RFC PATCH v1 2/2] softfloat: Add float128_to_uint32_round_to_zero()

[Peter Maydell]

On 7 February 2017 at 08:04, Bharata B Rao <bharata@linux.vnet.ibm.com> wrote:
> float128_to_uint32_round_to_zero() is needed by xscvqpuwz instruction
> of PowerPC ISA 3.0.
>
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> ---
>  fpu/softfloat.c         | 28 ++++++++++++++++++++++++++++
>  include/fpu/softfloat.h |  1 +
>  2 files changed, 29 insertions(+)
>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM

Re: [Qemu-devel] [RFC PATCH v1 1/2] softfloat: Add float128_to_uint64_round_to_zero()

[Peter Maydell]

On 7 February 2017 at 08:04, Bharata B Rao <bharata@linux.vnet.ibm.com> wrote:
> Implement float128_to_uint64() and use that to implement
> float128_to_uint64_round_to_zero()
>
> This is required by xscvqpudz instruction of PowerPC ISA 3.0.
>
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM

Re: [Qemu-devel] [RFC PATCH v1 2/2] softfloat: Add float128_to_uint32_round_to_zero()

[Richard Henderson]

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.


r~

Re: [Qemu-devel] [RFC PATCH v1 2/2] softfloat: Add float128_to_uint32_round_to_zero()

[Bharata B Rao]

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 <bharata@linux.vnet.ibm.com>
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 <bharata@linux.vnet.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
---
 fpu/softfloat.c         | 28 ++++++++++++++++++++++++++++
 include/fpu/softfloat.h |  1 +
 2 files changed, 29 insertions(+)

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);
-- 
2.7.4