arc: add missing files for fenv supportHEADmaster

2 files changed, 179 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/arc/bits/fenv.h b/libc/sysdeps/linux/arc/bits/fenv.h
new file mode 100644
index 000000000..c5c76cb93
--- /dev/null
+++ b/libc/sysdeps/linux/arc/bits/fenv.h
@@ -0,0 +1,75 @@
+/* Floating point environment.  ARC version.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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.
+
+   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 _FENV_H
+# error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
+#endif
+
+enum
+  {
+    FE_INVALID   =
+# define FE_INVALID	(0x01)
+      FE_INVALID,
+    FE_DIVBYZERO =
+# define FE_DIVBYZERO	(0x02)
+      FE_DIVBYZERO,
+    FE_OVERFLOW  =
+# define FE_OVERFLOW	(0x04)
+      FE_OVERFLOW,
+    FE_UNDERFLOW =
+# define FE_UNDERFLOW	(0x08)
+      FE_UNDERFLOW,
+    FE_INEXACT   =
+# define FE_INEXACT	(0x10)
+      FE_INEXACT
+  };
+
+# define FE_ALL_EXCEPT \
+	(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT)
+
+enum
+  {
+    FE_TOWARDZERO =
+# define FE_TOWARDZERO	(0x0)
+      FE_TOWARDZERO,
+    FE_TONEAREST  =
+# define FE_TONEAREST	(0x1)	/* default */
+      FE_TONEAREST,
+    FE_UPWARD     =
+# define FE_UPWARD	(0x2)
+      FE_UPWARD,
+    FE_DOWNWARD   =
+# define FE_DOWNWARD	(0x3)
+      FE_DOWNWARD
+  };
+
+typedef unsigned int fexcept_t;
+
+typedef struct
+{
+  unsigned int __fpcr;
+  unsigned int __fpsr;
+} fenv_t;
+
+/* If the default argument is used we use this value.  */
+#define FE_DFL_ENV	((const fenv_t *) -1)
+
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
diff --git a/libc/sysdeps/linux/arc/fpu_control.h b/libc/sysdeps/linux/arc/fpu_control.h
new file mode 100644
index 000000000..e833de3aa
--- /dev/null
+++ b/libc/sysdeps/linux/arc/fpu_control.h
@@ -0,0 +1,104 @@
+/* FPU control word bits.  ARC version.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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.
+
+   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 _FPU_CONTROL_H
+#define _FPU_CONTROL_H
+
+/* ARC FPU control register bits.
+
+  [  0] -> IVE: Enable invalid operation exception.
+           if 0, soft exception: status register IV flag set.
+           if 1, hardware exception trap (not supported in Linux yet).
+  [  1] -> DZE: Enable division by zero exception.
+           if 0, soft exception: status register IV flag set.
+           if 1, hardware exception: (not supported in Linux yet).
+  [9:8] -> RM: Rounding Mode:
+           00 - Rounding toward zero.
+           01 - Rounding to nearest (default).
+           10 - Rounding (up) toward plus infinity.
+           11 - Rounding (down)toward minus infinity.
+
+   ARC FPU status register bits.
+
+   [ 0] -> IV: flag invalid operation.
+   [ 1] -> DZ: flag division by zero.
+   [ 2] -> OV: flag Overflow operation.
+   [ 3] -> UV: flag Underflow operation.
+   [ 4] -> IX: flag Inexact operation.
+   [31] -> FWE: Flag Write Enable.
+           If 1, above flags writable explicitly (clearing),
+           else IoW and only writable indirectly via bits [12:7].  */
+
+#include <features.h>
+
+#if !defined(__ARC_FPU_SP__) &&  !defined(__ARC_FPU_DP__)
+
+# define _FPU_RESERVED 0xffffffff
+# define _FPU_DEFAULT  0x00000000
+typedef unsigned int fpu_control_t;
+# define _FPU_GETCW(cw) (cw) = 0
+# define _FPU_SETCW(cw) (void) (cw)
+# define _FPU_GETS(cw) (cw) = 0
+# define _FPU_SETS(cw) (void) (cw)
+extern fpu_control_t __fpu_control;
+
+#else
+
+#define _FPU_RESERVED		0
+
+/* The fdlibm code requires strict IEEE double precision arithmetic,
+   and no interrupts for exceptions, rounding to nearest.
+   So only RM set to b'01.  */
+# define _FPU_DEFAULT		0x00000100
+
+/* Actually default needs to have FWE bit as 1 but that is already
+   ingrained into _FPU_SETS macro below.  */
+#define  _FPU_FPSR_DEFAULT	0x00000000
+
+#define __FPU_RND_SHIFT		8
+#define __FPU_RND_MASK		0x3
+
+/* Type of the control word.  */
+typedef unsigned int fpu_control_t;
+
+/* Macros for accessing the hardware control word.  */
+#  define _FPU_GETCW(cw) __asm__ volatile ("lr %0, [0x300]" : "=r" (cw))
+#  define _FPU_SETCW(cw) __asm__ volatile ("sr %0, [0x300]" : : "r" (cw))
+
+/*  Macros for accessing the hardware status word.
+    Writing to FPU_STATUS requires a "control" bit FWE to be able to set the
+    exception flags directly (as opposed to side-effects of FP instructions).
+    That is done in the macro here to keeps callers agnostic of this detail.
+    And given FWE is write-only and RAZ, no need to "clear" it in _FPU_GETS
+    macro.  */
+#  define _FPU_GETS(cw)				\
+    __asm__ volatile ("lr   %0, [0x301]	\r\n" 	\
+                      : "=r" (cw))
+
+#  define _FPU_SETS(cw)				\
+    do {					\
+      unsigned int __fwe = 0x80000000 | (cw);	\
+      __asm__ volatile ("sr  %0, [0x301] \r\n" 	\
+                        : : "r" (__fwe));	\
+    } while (0)
+
+/* Default control word set at startup.  */
+extern fpu_control_t __fpu_control;
+
+#endif
+
+#endif /* fpu_control.h */