soft-fp: Add brain format support

In https://gcc.gnu.org/r13-3292 I've added brain format support
(std::bfloat16_t) on the GCC side, but as glibc has the master copy
of soft-fp, the following patch adds the files from that commit
and from https://gcc.gnu.org/r13-6598 and https://gcc.gnu.org/r13-6622
The files are not used by glibc right now.

12 files changed, 738 insertions, 0 deletions

diff --git a/soft-fp/brain.h b/soft-fp/brain.h
new file mode 100644
index 0000000000..84b24c9cb9
--- /dev/null
+++ b/soft-fp/brain.h
@@ -0,0 +1,172 @@
+/* Software floating-point emulation.
+   Definitions for Brain Floating Point format (bfloat16).
+   Copyright (C) 1997-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef SOFT_FP_BRAIN_H
+#define SOFT_FP_BRAIN_H	1
+
+#if _FP_W_TYPE_SIZE < 32
+# error "Here's a nickel kid.  Go buy yourself a real computer."
+#endif
+
+#define _FP_FRACTBITS_B		(_FP_W_TYPE_SIZE)
+
+#define _FP_FRACTBITS_DW_B	(_FP_W_TYPE_SIZE)
+
+#define _FP_FRACBITS_B		8
+#define _FP_FRACXBITS_B		(_FP_FRACTBITS_B - _FP_FRACBITS_B)
+#define _FP_WFRACBITS_B		(_FP_WORKBITS + _FP_FRACBITS_B)
+#define _FP_WFRACXBITS_B	(_FP_FRACTBITS_B - _FP_WFRACBITS_B)
+#define _FP_EXPBITS_B		8
+#define _FP_EXPBIAS_B		127
+#define _FP_EXPMAX_B		255
+
+#define _FP_QNANBIT_B		((_FP_W_TYPE) 1 << (_FP_FRACBITS_B-2))
+#define _FP_QNANBIT_SH_B	((_FP_W_TYPE) 1 << (_FP_FRACBITS_B-2+_FP_WORKBITS))
+#define _FP_IMPLBIT_B		((_FP_W_TYPE) 1 << (_FP_FRACBITS_B-1))
+#define _FP_IMPLBIT_SH_B	((_FP_W_TYPE) 1 << (_FP_FRACBITS_B-1+_FP_WORKBITS))
+#define _FP_OVERFLOW_B		((_FP_W_TYPE) 1 << (_FP_WFRACBITS_B))
+
+#define _FP_WFRACBITS_DW_B	(2 * _FP_WFRACBITS_B)
+#define _FP_WFRACXBITS_DW_B	(_FP_FRACTBITS_DW_B - _FP_WFRACBITS_DW_B)
+#define _FP_HIGHBIT_DW_B	\
+  ((_FP_W_TYPE) 1 << (_FP_WFRACBITS_DW_B - 1) % _FP_W_TYPE_SIZE)
+
+/* The implementation of _FP_MUL_MEAT_B and _FP_DIV_MEAT_B should be
+   chosen by the target machine.  */
+
+typedef float BFtype __attribute__ ((mode (BF)));
+
+union _FP_UNION_B
+{
+  BFtype flt;
+  struct _FP_STRUCT_LAYOUT
+  {
+#if __BYTE_ORDER == __BIG_ENDIAN
+    unsigned sign : 1;
+    unsigned exp  : _FP_EXPBITS_B;
+    unsigned frac : _FP_FRACBITS_B - (_FP_IMPLBIT_B != 0);
+#else
+    unsigned frac : _FP_FRACBITS_B - (_FP_IMPLBIT_B != 0);
+    unsigned exp  : _FP_EXPBITS_B;
+    unsigned sign : 1;
+#endif
+  } bits;
+};
+
+#define FP_DECL_B(X)		_FP_DECL (1, X)
+#define FP_UNPACK_RAW_B(X, val)	_FP_UNPACK_RAW_1 (B, X, (val))
+#define FP_UNPACK_RAW_BP(X, val)	_FP_UNPACK_RAW_1_P (B, X, (val))
+#define FP_PACK_RAW_B(val, X)	_FP_PACK_RAW_1 (B, (val), X)
+#define FP_PACK_RAW_BP(val, X)			\
+  do						\
+    {						\
+      if (!FP_INHIBIT_RESULTS)			\
+	_FP_PACK_RAW_1_P (B, (val), X);		\
+    }						\
+  while (0)
+
+#define FP_UNPACK_B(X, val)			\
+  do						\
+    {						\
+      _FP_UNPACK_RAW_1 (B, X, (val));		\
+      _FP_UNPACK_CANONICAL (B, 1, X);		\
+    }						\
+  while (0)
+
+#define FP_UNPACK_BP(X, val)			\
+  do						\
+    {						\
+      _FP_UNPACK_RAW_1_P (B, X, (val));		\
+      _FP_UNPACK_CANONICAL (B, 1, X);		\
+    }						\
+  while (0)
+
+#define FP_UNPACK_SEMIRAW_B(X, val)		\
+  do						\
+    {						\
+      _FP_UNPACK_RAW_1 (B, X, (val));		\
+      _FP_UNPACK_SEMIRAW (B, 1, X);		\
+    }						\
+  while (0)
+
+#define FP_UNPACK_SEMIRAW_BP(X, val)		\
+  do						\
+    {						\
+      _FP_UNPACK_RAW_1_P (B, X, (val));		\
+      _FP_UNPACK_SEMIRAW (B, 1, X);		\
+    }						\
+  while (0)
+
+#define FP_PACK_B(val, X)			\
+  do						\
+    {						\
+      _FP_PACK_CANONICAL (B, 1, X);		\
+      _FP_PACK_RAW_1 (B, (val), X);		\
+    }						\
+  while (0)
+
+#define FP_PACK_BP(val, X)			\
+  do						\
+    {						\
+      _FP_PACK_CANONICAL (B, 1, X);		\
+      if (!FP_INHIBIT_RESULTS)			\
+	_FP_PACK_RAW_1_P (B, (val), X);		\
+    }						\
+  while (0)
+
+#define FP_PACK_SEMIRAW_B(val, X)		\
+  do						\
+    {						\
+      _FP_PACK_SEMIRAW (B, 1, X);		\
+      _FP_PACK_RAW_1 (B, (val), X);		\
+    }						\
+  while (0)
+
+#define FP_PACK_SEMIRAW_BP(val, X)		\
+  do						\
+    {						\
+      _FP_PACK_SEMIRAW (B, 1, X);		\
+      if (!FP_INHIBIT_RESULTS)			\
+	_FP_PACK_RAW_1_P (B, (val), X);		\
+    }						\
+  while (0)
+
+#define FP_TO_INT_B(r, X, rsz, rsg)	_FP_TO_INT (B, 1, (r), X, (rsz), (rsg))
+#define FP_TO_INT_ROUND_B(r, X, rsz, rsg)	\
+  _FP_TO_INT_ROUND (B, 1, (r), X, (rsz), (rsg))
+#define FP_FROM_INT_B(X, r, rs, rt)	_FP_FROM_INT (B, 1, X, (r), (rs), rt)
+
+/* BFmode arithmetic is not implemented.  */
+
+#define _FP_FRAC_HIGH_B(X)	_FP_FRAC_HIGH_1 (X)
+#define _FP_FRAC_HIGH_RAW_B(X)	_FP_FRAC_HIGH_1 (X)
+#define _FP_FRAC_HIGH_DW_B(X)	_FP_FRAC_HIGH_1 (X)
+
+#define FP_CMP_EQ_B(r, X, Y, ex)       _FP_CMP_EQ (B, 1, (r), X, Y, (ex))
+
+#endif /* !SOFT_FP_BRAIN_H */
diff --git a/soft-fp/extendbfsf2.c b/soft-fp/extendbfsf2.c
new file mode 100644
index 0000000000..dd1a20f81b
--- /dev/null
+++ b/soft-fp/extendbfsf2.c
@@ -0,0 +1,49 @@
+/* Software floating-point emulation.
+   Return an bfloat16 converted to IEEE single
+   Copyright (C) 2022-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define FP_NO_EXACT_UNDERFLOW
+#include "soft-fp.h"
+#include "brain.h"
+#include "single.h"
+
+SFtype
+__extendbfsf2 (BFtype a)
+{
+  FP_DECL_EX;
+  FP_DECL_B (A);
+  FP_DECL_S (R);
+  SFtype r;
+
+  FP_INIT_EXCEPTIONS;
+  FP_UNPACK_RAW_B (A, a);
+  FP_EXTEND (S, B, 1, 1, R, A);
+  FP_PACK_RAW_S (r, R);
+  FP_HANDLE_EXCEPTIONS;
+
+  return r;
+}
diff --git a/soft-fp/floatdibf.c b/soft-fp/floatdibf.c
new file mode 100644
index 0000000000..53ac77231e
--- /dev/null
+++ b/soft-fp/floatdibf.c
@@ -0,0 +1,45 @@
+/* Software floating-point emulation.
+   Convert a 64bit signed integer to bfloat16
+   Copyright (C) 2007-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+
+BFtype
+__floatdibf (DItype i)
+{
+  FP_DECL_EX;
+  FP_DECL_B (A);
+  BFtype a;
+
+  FP_INIT_ROUNDMODE;
+  FP_FROM_INT_B (A, i, DI_BITS, UDItype);
+  FP_PACK_RAW_B (a, A);
+  FP_HANDLE_EXCEPTIONS;
+
+  return a;
+}
diff --git a/soft-fp/floattibf.c b/soft-fp/floattibf.c
new file mode 100644
index 0000000000..2b8eed162f
--- /dev/null
+++ b/soft-fp/floattibf.c
@@ -0,0 +1,45 @@
+/* Software floating-point emulation.
+   Convert a 128bit signed integer to bfloat16
+   Copyright (C) 2007-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+
+BFtype
+__floattibf (TItype i)
+{
+  FP_DECL_EX;
+  FP_DECL_B (A);
+  BFtype a;
+
+  FP_INIT_ROUNDMODE;
+  FP_FROM_INT_B (A, i, TI_BITS, UTItype);
+  FP_PACK_RAW_B (a, A);
+  FP_HANDLE_EXCEPTIONS;
+
+  return a;
+}
diff --git a/soft-fp/floatundibf.c b/soft-fp/floatundibf.c
new file mode 100644
index 0000000000..059fece293
--- /dev/null
+++ b/soft-fp/floatundibf.c
@@ -0,0 +1,45 @@
+/* Software floating-point emulation.
+   Convert a 64bit unsigned integer to bfloat16
+   Copyright (C) 2007-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+
+BFtype
+__floatundibf (UDItype i)
+{
+  FP_DECL_EX;
+  FP_DECL_B (A);
+  BFtype a;
+
+  FP_INIT_ROUNDMODE;
+  FP_FROM_INT_B (A, i, DI_BITS, UDItype);
+  FP_PACK_RAW_B (a, A);
+  FP_HANDLE_EXCEPTIONS;
+
+  return a;
+}
diff --git a/soft-fp/floatuntibf.c b/soft-fp/floatuntibf.c
new file mode 100644
index 0000000000..eec50acd77
--- /dev/null
+++ b/soft-fp/floatuntibf.c
@@ -0,0 +1,45 @@
+/* Software floating-point emulation.
+   Convert a 128bit unsigned integer to bfloat16
+   Copyright (C) 2007-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+
+BFtype
+__floatuntibf (UTItype i)
+{
+  FP_DECL_EX;
+  FP_DECL_B (A);
+  BFtype a;
+
+  FP_INIT_ROUNDMODE;
+  FP_FROM_INT_B (A, i, TI_BITS, UTItype);
+  FP_PACK_RAW_B (a, A);
+  FP_HANDLE_EXCEPTIONS;
+
+  return a;
+}
diff --git a/soft-fp/truncbfhf2.c b/soft-fp/truncbfhf2.c
new file mode 100644
index 0000000000..627f8c6559
--- /dev/null
+++ b/soft-fp/truncbfhf2.c
@@ -0,0 +1,75 @@
+/* Software floating-point emulation.
+   Truncate bfloat16 into IEEE half.
+   Copyright (C) 2022-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "half.h"
+#include "brain.h"
+#include "single.h"
+
+/* BFtype and HFtype are unordered, neither is a superset or subset
+   of each other.  Convert BFtype to SFtype (lossless) and then
+   truncate to HFtype.  */
+
+HFtype
+__truncbfhf2 (BFtype a)
+{
+  FP_DECL_EX;
+  FP_DECL_H (A);
+  FP_DECL_S (B);
+  FP_DECL_B (R);
+  SFtype b;
+  HFtype r;
+
+  FP_INIT_ROUNDMODE;
+  /* Optimize BFtype to SFtype conversion to simple left shift
+     by 16 if possible, we don't need to raise exceptions on sNaN
+     here as the SFtype to HFtype truncation should do that too.  */
+  if (sizeof (BFtype) == 2
+      && sizeof (unsigned short) == 2
+      && sizeof (SFtype) == 4
+      && sizeof (unsigned int) == 4)
+    {
+      union { BFtype a; unsigned short b; } u1;
+      union { SFtype a; unsigned int b; } u2;
+      u1.a = a;
+      u2.b = (u1.b << 8) << 8;
+      b = u2.a;
+    }
+  else
+    {
+      FP_UNPACK_RAW_B (A, a);
+      FP_EXTEND (S, B, 1, 1, B, A);
+      FP_PACK_RAW_S (b, B);
+    }
+  FP_UNPACK_SEMIRAW_S (B, b);
+  FP_TRUNC (H, S, 1, 1, R, B);
+  FP_PACK_SEMIRAW_H (r, R);
+  FP_HANDLE_EXCEPTIONS;
+
+  return r;
+}
diff --git a/soft-fp/truncdfbf2.c b/soft-fp/truncdfbf2.c
new file mode 100644
index 0000000000..3d80a96a02
--- /dev/null
+++ b/soft-fp/truncdfbf2.c
@@ -0,0 +1,52 @@
+/* Software floating-point emulation.
+   Truncate IEEE double into bfloat16.
+   Copyright (C) 2022-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+#include "double.h"
+
+BFtype
+__truncdfbf2 (DFtype a)
+{
+  FP_DECL_EX;
+  FP_DECL_D (A);
+  FP_DECL_B (R);
+  BFtype r;
+
+  FP_INIT_ROUNDMODE;
+  FP_UNPACK_SEMIRAW_D (A, a);
+#if _FP_W_TYPE_SIZE < _FP_FRACBITS_D
+  FP_TRUNC (B, D, 1, 2, R, A);
+#else
+  FP_TRUNC (B, D, 1, 1, R, A);
+#endif
+  FP_PACK_SEMIRAW_B (r, R);
+  FP_HANDLE_EXCEPTIONS;
+
+  return r;
+}
diff --git a/soft-fp/trunchfbf2.c b/soft-fp/trunchfbf2.c
new file mode 100644
index 0000000000..ad5fbbd654
--- /dev/null
+++ b/soft-fp/trunchfbf2.c
@@ -0,0 +1,58 @@
+/* Software floating-point emulation.
+   Truncate IEEE half into bfloat16.
+   Copyright (C) 2022-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+#include "half.h"
+#include "single.h"
+
+/* BFtype and HFtype are unordered, neither is a superset or subset
+   of each other.  Convert HFtype to SFtype (lossless) and then
+   truncate to BFtype.  */
+
+BFtype
+__trunchfbf2 (HFtype a)
+{
+  FP_DECL_EX;
+  FP_DECL_H (A);
+  FP_DECL_S (B);
+  FP_DECL_B (R);
+  SFtype b;
+  BFtype r;
+
+  FP_INIT_ROUNDMODE;
+  FP_UNPACK_RAW_H (A, a);
+  FP_EXTEND (S, H, 1, 1, B, A);
+  FP_PACK_RAW_S (b, B);
+  FP_UNPACK_SEMIRAW_S (B, b);
+  FP_TRUNC (B, S, 1, 1, R, B);
+  FP_PACK_SEMIRAW_B (r, R);
+  FP_HANDLE_EXCEPTIONS;
+
+  return r;
+}
diff --git a/soft-fp/truncsfbf2.c b/soft-fp/truncsfbf2.c
new file mode 100644
index 0000000000..28652c3cc8
--- /dev/null
+++ b/soft-fp/truncsfbf2.c
@@ -0,0 +1,48 @@
+/* Software floating-point emulation.
+   Truncate IEEE single into bfloat16.
+   Copyright (C) 2022-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+#include "single.h"
+
+BFtype
+__truncsfbf2 (SFtype a)
+{
+  FP_DECL_EX;
+  FP_DECL_S (A);
+  FP_DECL_B (R);
+  BFtype r;
+
+  FP_INIT_ROUNDMODE;
+  FP_UNPACK_SEMIRAW_S (A, a);
+  FP_TRUNC (B, S, 1, 1, R, A);
+  FP_PACK_SEMIRAW_B (r, R);
+  FP_HANDLE_EXCEPTIONS;
+
+  return r;
+}
diff --git a/soft-fp/trunctfbf2.c b/soft-fp/trunctfbf2.c
new file mode 100644
index 0000000000..f9dc20d7b9
--- /dev/null
+++ b/soft-fp/trunctfbf2.c
@@ -0,0 +1,52 @@
+/* Software floating-point emulation.
+   Truncate IEEE quad into bfloat16.
+   Copyright (C) 2022-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+#include "quad.h"
+
+BFtype
+__trunctfbf2 (TFtype a)
+{
+  FP_DECL_EX;
+  FP_DECL_Q (A);
+  FP_DECL_B (R);
+  BFtype r;
+
+  FP_INIT_ROUNDMODE;
+  FP_UNPACK_SEMIRAW_Q (A, a);
+#if _FP_W_TYPE_SIZE < 64
+  FP_TRUNC (B, Q, 1, 4, R, A);
+#else
+  FP_TRUNC (B, Q, 1, 2, R, A);
+#endif
+  FP_PACK_SEMIRAW_B (r, R);
+  FP_HANDLE_EXCEPTIONS;
+
+  return r;
+}
diff --git a/soft-fp/truncxfbf2.c b/soft-fp/truncxfbf2.c
new file mode 100644
index 0000000000..bdce6c75df
--- /dev/null
+++ b/soft-fp/truncxfbf2.c
@@ -0,0 +1,52 @@
+/* Software floating-point emulation.
+   Truncate IEEE extended into bfloat16.
+   Copyright (C) 2022-2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   In addition to the permissions in the GNU Lesser General Public
+   License, the Free Software Foundation gives you unlimited
+   permission to link the compiled version of this file into
+   combinations with other programs, and to distribute those
+   combinations without any restriction coming from the use of this
+   file.  (The Lesser General Public License restrictions do apply in
+   other respects; for example, they cover modification of the file,
+   and distribution when not linked into a combine executable.)
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "soft-fp.h"
+#include "brain.h"
+#include "extended.h"
+
+BFtype
+__truncxfbf2 (XFtype a)
+{
+  FP_DECL_EX;
+  FP_DECL_E (A);
+  FP_DECL_B (R);
+  BFtype r;
+
+  FP_INIT_ROUNDMODE;
+  FP_UNPACK_SEMIRAW_E (A, a);
+#if _FP_W_TYPE_SIZE < 64
+  FP_TRUNC (B, E, 1, 4, R, A);
+#else
+  FP_TRUNC (B, E, 1, 2, R, A);
+#endif
+  FP_PACK_SEMIRAW_B (r, R);
+  FP_HANDLE_EXCEPTIONS;
+
+  return r;
+}