m68k: really add fenv from musl-1.1.24

Somehow the first review merged only the commit log.

FreeBSD doesn't have m68k anyway, so use fenv from musl with as less
changes as possible.

Change-Id: I6372af6679e6773fbb6bf4c8b5b30512971a97a6
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3161
Reviewed-by: Alex von Gluck IV <[email protected]>

headers/posix/arch/m68k/fenv.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2005-2019 Rich Felker, et al.
+ *
+ * Part of MUSL, released under the MIT license.
+ */
+
+
+#ifndef _FENV_H_
+#define _FENV_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if __HAVE_68881__ || __mcffpu__
+
+#define FE_INEXACT    8
+#define FE_DIVBYZERO  16
+#define FE_UNDERFLOW  32
+#define FE_OVERFLOW   64
+#define FE_INVALID    128
+
+#define FE_ALL_EXCEPT 0xf8
+
+#define FE_TONEAREST  0
+#define FE_TOWARDZERO 16
+#define FE_DOWNWARD   32
+#define FE_UPWARD     48
+
+#else
+
+#define FE_ALL_EXCEPT 0
+#define FE_TONEAREST  0
+
+#endif
+
+typedef unsigned fexcept_t;
+
+typedef struct {
+	unsigned __control_register, __status_register, __instruction_address;
+} fenv_t;
+
+#define FE_DFL_ENV      ((const fenv_t *) -1)
+
+int feclearexcept(int);
+int fegetexceptflag(fexcept_t *, int);
+int feraiseexcept(int);
+int fesetexceptflag(const fexcept_t *, int);
+int fetestexcept(int);
+
+int fegetround(void);
+int fesetround(int);
+
+int fegetenv(fenv_t *);
+int feholdexcept(fenv_t *);
+int fesetenv(const fenv_t *);
+int feupdateenv(const fenv_t *);
+
+#ifdef __cplusplus
+}
+#endif
+#endif
+

headers/posix/fenv.h

@@ -15,6 +15,8 @@
 #  include <arch/riscv64/fenv.h>
 #elif defined(__sparc__)
 #  include <arch/sparc64/fenv.h>
+#elif defined(__M68K__)
+#  include <arch/m68k/fenv.h>
 #else
 #  error There is no fenv.h for this architecture!
 #endif

src/system/libroot/posix/arch/generic/fenv-generic.c

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2005-2019 Rich Felker, et al.
+ *
+ * Part of MUSL, released under the MIT license.
+ */
+
+
+#include <fenv.h>
+
+/* Dummy functions for archs lacking fenv implementation */
+
+int feclearexcept(int mask)
+{
+	return 0;
+}
+
+int feraiseexcept(int mask)
+{
+	return 0;
+}
+
+int fetestexcept(int mask)
+{
+	return 0;
+}
+
+int fegetround(void)
+{
+	return FE_TONEAREST;
+}
+
+int __fesetround(int r)
+{
+	return 0;
+}
+
+int fegetenv(fenv_t *envp)
+{
+	return 0;
+}
+
+int fesetenv(const fenv_t *envp)
+{
+	return 0;
+}

src/system/libroot/posix/arch/generic/fesetround.c

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2005-2019 Rich Felker, et al.
+ *
+ * Part of MUSL, released under the MIT license.
+ */
+
+
+#include <fenv.h>
+#include <features.h>
+
+#define hidden __attribute__((__visibility__("hidden")))
+
+/* __fesetround wrapper for arch independent argument check */
+
+hidden int __fesetround(int);
+
+int fesetround(int r)
+{
+	if (r != FE_TONEAREST
+#ifdef FE_DOWNWARD
+		&& r != FE_DOWNWARD
+#endif
+#ifdef FE_UPWARD
+		&& r != FE_UPWARD
+#endif
+#ifdef FE_TOWARDZERO
+		&& r != FE_TOWARDZERO
+#endif
+	)
+		return -1;
+	return __fesetround(r);
+}

src/system/libroot/posix/arch/m68k/Jamfile

@@ -3,13 +3,17 @@ SubDir HAIKU_TOP src system libroot posix arch m68k ;
 local architecture = $(TARGET_ARCH) ;
 
 UsePrivateSystemHeaders ;
+UseHeaders [ FDirName $(HAIKU_TOP) headers compatibility bsd ] : true ;
+#SubDirCcFlags -save-temps ;
 
 local genericSources =
+	fesetround.c
 	setjmp_save_sigs.c
 	longjmp_return.c
 ;
 
 MergeObject <$(TARGET_ARCH)>posix_arch_$(TARGET_ARCH).o :
+	fenv.c
 	sigsetjmp.S
 	siglongjmp.S
 

src/system/libroot/posix/arch/m68k/fenv.c

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2005-2019 Rich Felker, et al.
+ *
+ * Part of MUSL, released under the MIT license.
+ */
+
+
+#include <fenv.h>
+#include <features.h>
+
+#define hidden __attribute__((__visibility__("hidden")))
+
+#if __HAVE_68881__ || __mcffpu__
+
+static unsigned getsr()
+{
+	unsigned v;
+	__asm__ __volatile__ ("fmove.l %%fpsr,%0" : "=dm"(v));
+	return v;
+}
+
+static void setsr(unsigned v)
+{
+	__asm__ __volatile__ ("fmove.l %0,%%fpsr" : : "dm"(v));
+}
+
+static unsigned getcr()
+{
+	unsigned v;
+	__asm__ __volatile__ ("fmove.l %%fpcr,%0" : "=dm"(v));
+	return v;
+}
+
+static void setcr(unsigned v)
+{
+	__asm__ __volatile__ ("fmove.l %0,%%fpcr" : : "dm"(v));
+}
+
+int feclearexcept(int mask)
+{
+	if (mask & ~FE_ALL_EXCEPT) return -1;
+	setsr(getsr() & ~mask);
+	return 0;
+}
+
+int feraiseexcept(int mask)
+{
+	if (mask & ~FE_ALL_EXCEPT) return -1;
+	setsr(getsr() | mask);
+	return 0;
+}
+
+int fetestexcept(int mask)
+{
+	return getsr() & mask;
+}
+
+int fegetround(void)
+{
+	return getcr() & FE_UPWARD;
+}
+
+hidden int __fesetround(int r)
+{
+	setcr((getcr() & ~FE_UPWARD) | r);
+	return 0;
+}
+
+int fegetenv(fenv_t *envp)
+{
+	envp->__control_register = getcr();
+	envp->__status_register = getsr();
+	__asm__ __volatile__ ("fmove.l %%fpiar,%0"
+		: "=dm"(envp->__instruction_address));
+	return 0;
+}
+
+int fesetenv(const fenv_t *envp)
+{
+	static const fenv_t default_env = { 0 };
+	if (envp == FE_DFL_ENV)
+		envp = &default_env;
+	setcr(envp->__control_register);
+	setsr(envp->__status_register);
+	__asm__ __volatile__ ("fmove.l %0,%%fpiar"
+		: : "dm"(envp->__instruction_address));
+	return 0;
+}
+
+#else
+
+#include "fenv-generic.c"
+
+#endif