Merge remote-tracking branch 'remotes/stsquad/tags/pull-softfloat-refactor-210218-1' into staging

This is the re-factor of softfloat:

  - shared common code path float16/32/64
  - well commented and easy to follow code
  - added a bunch of float16 support

While some operations are slower the key ones exercised by the
floating point dbt-bench are the same: https://i.imgur.com/oXNJNql.png

# gpg: Signature made Wed 21 Feb 2018 10:44:14 GMT
# gpg:                using RSA key FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>"
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-softfloat-refactor-210218-1: (22 commits)
  fpu/softfloat: re-factor sqrt
  fpu/softfloat: re-factor compare
  fpu/softfloat: re-factor minmax
  fpu/softfloat: re-factor scalbn
  fpu/softfloat: re-factor int/uint to float
  fpu/softfloat: re-factor float to int/uint
  fpu/softfloat: re-factor round_to_int
  fpu/softfloat: re-factor muladd
  fpu/softfloat: re-factor div
  fpu/softfloat: re-factor mul
  fpu/softfloat: re-factor add/sub
  fpu/softfloat: define decompose structures
  fpu/softfloat: move the extract functions to the top of the file
  fpu/softfloat: improve comments on ARM NaN propagation
  include/fpu/softfloat: add some float16 constants
  include/fpu/softfloat: implement float16_set_sign helper
  include/fpu/softfloat: implement float16_chs helper
  include/fpu/softfloat: implement float16_abs helper
  target/*/cpu.h: remove softfloat.h
  fpu/softfloat-types: new header to prevent excessive re-builds
  ...

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

1 files changed, 179 insertions, 0 deletions

diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
new file mode 100644
index 0000000000..4e378cb612
--- /dev/null
+++ b/include/fpu/softfloat-types.h
@@ -0,0 +1,179 @@
+/*
+ * QEMU float support
+ *
+ * The code in this source file is derived from release 2a of the SoftFloat
+ * IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and
+ * some later contributions) are provided under that license, as detailed below.
+ * It has subsequently been modified by contributors to the QEMU Project,
+ * so some portions are provided under:
+ *  the SoftFloat-2a license
+ *  the BSD license
+ *  GPL-v2-or-later
+ *
+ * This header holds definitions for code that might be dealing with
+ * softfloat types but not need access to the actual library functions.
+ */
+/*
+===============================================================================
+This C header file is part of the SoftFloat IEC/IEEE Floating-point
+Arithmetic Package, Release 2a.
+
+Written by John R. Hauser.  This work was made possible in part by the
+International Computer Science Institute, located at Suite 600, 1947 Center
+Street, Berkeley, California 94704.  Funding was partially provided by the
+National Science Foundation under grant MIP-9311980.  The original version
+of this code was written as part of a project to build a fixed-point vector
+processor in collaboration with the University of California at Berkeley,
+overseen by Profs. Nelson Morgan and John Wawrzynek.  More information
+is available through the Web page `http://HTTP.CS.Berkeley.EDU/~jhauser/
+arithmetic/SoftFloat.html'.
+
+THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE.  Although reasonable effort
+has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
+TIMES RESULT IN INCORRECT BEHAVIOR.  USE OF THIS SOFTWARE IS RESTRICTED TO
+PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
+AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
+
+Derivative works are acceptable, even for commercial purposes, so long as
+(1) they include prominent notice that the work is derivative, and (2) they
+include prominent notice akin to these four paragraphs for those parts of
+this code that are retained.
+
+===============================================================================
+*/
+
+/* BSD licensing:
+ * Copyright (c) 2006, Fabrice Bellard
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* Portions of this work are licensed under the terms of the GNU GPL,
+ * version 2 or later. See the COPYING file in the top-level directory.
+ */
+
+#ifndef SOFTFLOAT_TYPES_H
+#define SOFTFLOAT_TYPES_H
+
+/* This 'flag' type must be able to hold at least 0 and 1. It should
+ * probably be replaced with 'bool' but the uses would need to be audited
+ * to check that they weren't accidentally relying on it being a larger type.
+ */
+typedef uint8_t flag;
+
+/*
+ * Software IEC/IEEE floating-point types.
+ */
+
+typedef uint16_t float16;
+typedef uint32_t float32;
+typedef uint64_t float64;
+#define float16_val(x) (x)
+#define float32_val(x) (x)
+#define float64_val(x) (x)
+#define make_float16(x) (x)
+#define make_float32(x) (x)
+#define make_float64(x) (x)
+#define const_float16(x) (x)
+#define const_float32(x) (x)
+#define const_float64(x) (x)
+typedef struct {
+    uint64_t low;
+    uint16_t high;
+} floatx80;
+#define make_floatx80(exp, mant) ((floatx80) { mant, exp })
+#define make_floatx80_init(exp, mant) { .low = mant, .high = exp }
+typedef struct {
+#ifdef HOST_WORDS_BIGENDIAN
+    uint64_t high, low;
+#else
+    uint64_t low, high;
+#endif
+} float128;
+#define make_float128(high_, low_) ((float128) { .high = high_, .low = low_ })
+#define make_float128_init(high_, low_) { .high = high_, .low = low_ }
+
+/*
+ * Software IEC/IEEE floating-point underflow tininess-detection mode.
+ */
+
+enum {
+    float_tininess_after_rounding  = 0,
+    float_tininess_before_rounding = 1
+};
+
+/*
+ *Software IEC/IEEE floating-point rounding mode.
+ */
+
+enum {
+    float_round_nearest_even = 0,
+    float_round_down         = 1,
+    float_round_up           = 2,
+    float_round_to_zero      = 3,
+    float_round_ties_away    = 4,
+    /* Not an IEEE rounding mode: round to the closest odd mantissa value */
+    float_round_to_odd       = 5,
+};
+
+/*
+ * Software IEC/IEEE floating-point exception flags.
+ */
+
+enum {
+    float_flag_invalid   =  1,
+    float_flag_divbyzero =  4,
+    float_flag_overflow  =  8,
+    float_flag_underflow = 16,
+    float_flag_inexact   = 32,
+    float_flag_input_denormal = 64,
+    float_flag_output_denormal = 128
+};
+
+
+/*
+ * Floating Point Status. Individual architectures may maintain
+ * several versions of float_status for different functions. The
+ * correct status for the operation is then passed by reference to
+ * most of the softfloat functions.
+ */
+
+typedef struct float_status {
+    signed char float_detect_tininess;
+    signed char float_rounding_mode;
+    uint8_t     float_exception_flags;
+    signed char floatx80_rounding_precision;
+    /* should denormalised results go to zero and set the inexact flag? */
+    flag flush_to_zero;
+    /* should denormalised inputs go to zero and set the input_denormal flag? */
+    flag flush_inputs_to_zero;
+    flag default_nan_mode;
+    flag snan_bit_is_one;
+} float_status;
+
+#endif /* SOFTFLOAT_TYPES_H */