bsd-user: introduce target.h

Create target.h. This file is intended to be simple and describe basic
things about the architecture. If something is a basic feature of the
architecture, it belongs here. Should we need something that's per-BSD
there will be a target-os.h that will live in the per-bsd directories.

Define regpairs_aligned to reflect whether or not registers are 'paired'
for 64-bit arguments or not. This will be false for all 64-bit targets,
and will be true on those architectures that pair (currently just armv7
and powerpc on FreeBSD 14.x).

Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Kyle Evans <kevans@FreeBSD.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

bsd-user/arm/target.h

@@ -0,0 +1,21 @@
+/*
+ * Intel general target stuff that's common to all i386 details
+ *
+ * Copyright (c) 2022 M. Warner Losh <imp@bsdimp.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef TARGET_H
+#define TARGET_H
+
+/*
+ * arm EABI 'lumps' the registers for 64-bit args.
+ */
+static inline bool regpairs_aligned(void *cpu_env)
+{
+    return true;
+}
+
+#endif /* ! TARGET_H */
+

bsd-user/i386/target.h

@@ -0,0 +1,21 @@
+/*
+ * Intel general target stuff that's common to all i386 details
+ *
+ * Copyright (c) 2022 M. Warner Losh <imp@bsdimp.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef TARGET_ARCH_H
+#define TARGET_ARCH_H
+
+/*
+ * i386 doesn't 'lump' the registers for 64-bit args.
+ */
+static inline bool regpairs_aligned(void *cpu_env)
+{
+    return false;
+}
+
+#endif /* ! TARGET_ARCH_H */
+

bsd-user/qemu.h

@@ -35,6 +35,7 @@ extern char **environ;
 #include "target_syscall.h"
 #include "target_os_vmparam.h"
 #include "target_os_signal.h"
+#include "target.h"
 #include "exec/gdbstub.h"
 
 /*

bsd-user/x86_64/target.h

@@ -0,0 +1,21 @@
+/*
+ * Intel general target stuff that's common to all x86_64 details
+ *
+ * Copyright (c) 2022 M. Warner Losh <imp@bsdimp.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef TARGET_H
+#define TARGET_H
+
+/*
+ * x86 doesn't 'lump' the registers for 64-bit args, all args are 64 bits.
+ */
+static inline bool regpairs_aligned(void *cpu_env)
+{
+    return false;
+}
+
+#endif /* ! TARGET_H */
+