[newlib-cygwin] Cygwin: add local machine/asm.h header

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=8e83ca675f522d132ca35d847aa35f310951702e

commit 8e83ca675f522d132ca35d847aa35f310951702e
Author:     Corinna Vinschen <corinna@vinschen.de>
AuthorDate: Tue Dec 20 09:56:39 2022 +0100
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Tue Dec 20 10:13:59 2022 +0100

    Cygwin: add local machine/asm.h header
    
    This header supports including BSD assembler sources.
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 winsup/cygwin/local_includes/machine/asm.h | 78 ++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/winsup/cygwin/local_includes/machine/asm.h b/winsup/cygwin/local_includes/machine/asm.h
new file mode 100644
index 000000000000..12b0285396ff
--- /dev/null
+++ b/winsup/cygwin/local_includes/machine/asm.h
@@ -0,0 +1,78 @@
+#ifndef _MACHINE_ASM_H
+#define _MACHINE_ASM_H
+
+/* Macros for importing FreeBSD/OpenBSD/NetBSD assembler code. */
+
+#ifdef __x86_64__
+
+#define _ALIGN_TEXT		.p2align 4,0x90
+
+/* The NATIVE_ENTRY macro just adds the required gas macros.  It can be
+   used stand-alone if the code is so short that it's better to change the
+   argument registeres rather than adding the code overhead. */
+
+#define NATIVE_ENTRY(__sym)		 \
+		.text			;\
+		.p2align 4		;\
+		.globl __sym		;\
+		.seh_proc __sym		;\
+	__sym:				 \
+
+/* The ENTRY macros cover the difference in argument passing between
+   MS-ABI and SysV ABI.  Note especially that RSI/RDI are always saved
+   in the stack shadow space defined by the MS_ABI, and restored when
+   calling ret (see the "ret" macro below). */
+
+#define __ENTRY(__sym)			 \
+		NATIVE_ENTRY(__sym)	 \
+		movq	%rsi,8(%rsp)	;\
+		movq	%rdi,16(%rsp)	;
+
+/* ENTRY1 for functions with 1 arg */
+#define ENTRY1(__sym)			 \
+		__ENTRY(__sym)		 \
+		movq	%rcx,%rdi	;\
+		.seh_endprologue	;
+
+/* ENTRY2 for functions with 2 args */
+#define ENTRY2(__sym)			 \
+		__ENTRY(__sym)		 \
+		movq	%rcx,%rdi	;\
+		movq	%rdx,%rsi	;\
+		.seh_endprologue	;
+
+/* ENTRY3 for functions with 3 args */
+#define ENTRY3(__sym)			 \
+		__ENTRY(__sym)		 \
+		movq	%rcx,%rdi	;\
+		movq	%rdx,%rsi	;\
+		movq	%r8,%rdx	;\
+		.seh_endprologue	;
+
+/* ENTRY4 for functions with 4 args */
+#define ENTRY4(__sym)			 \
+		__ENTRY(__sym)		 \
+		movq	%rcx,%rdi	;\
+		movq	%rdx,%rsi	;\
+		movq	%r8,%rdx	;\
+		movq	%r9,%rcx	;\
+		.seh_endprologue	;
+
+#define ret				 \
+		movq	8(%rsp),%rsi	;\
+		movq	16(%rsp),%rdi	;\
+		retq			;\
+
+#define END(__sym)			 \
+		.seh_endproc
+
+#endif /* __x86_64__ */
+
+#define __FBSDID(s)			 \
+		.ident s
+
+#define STRONG_ALIAS(__a,__s)		 \
+		.globl	__a		;\
+		__a = __s		;
+
+#endif /* _MACHINE_ASM_H */