20000317 sourceware import

libgloss/sparc/libsys/syscallasm.h

@@ -0,0 +1,93 @@
+#ifndef _SYSCALLASM_H_
+#define _SYSCALLASM_H_
+
+/*
+ * This file defines the system calls for SPARC for the assembler.
+ * Anything C-ish is not allowed in this file.
+ * C files should include syscall.h.
+ */
+
+#include "syscall.h"
+
+/* Some macros for writing assember syscall stubs.  */
+
+#ifdef SVR4
+#define TEXT_SECTION	.section ".text"
+#define DATA_SECTION	.section ".data"
+#define ALIGN(x)	.align x
+#define GLOBAL(sym)	.global sym
+#define WORD(x)		.long x
+#define ASM_SYMBOL(name) name
+#define ASM_PRIVATE_SYMBOL(name) _##name
+#define SYSCALL_TRAP	8
+#else
+#define TEXT_SECTION	.text
+#define DATA_SECTION	.data
+#define ALIGN(x)	.align x
+#define GLOBAL(sym)	.global sym
+#define WORD(x)		.word x
+#define ASM_SYMBOL(name) _##name
+#define ASM_PRIVATE_SYMBOL(name) name
+#define SYSCALL_TRAP	0
+#endif
+
+#define defsyscall(name, n) \
+	TEXT_SECTION ;			\
+	ALIGN (4) ;			\
+	GLOBAL (ASM_SYMBOL (name)) ;	\
+ASM_SYMBOL (name):			\
+	mov	n,%g1 ;			\
+	ta	SYSCALL_TRAP ;		\
+	bcc	noerr ;			\
+	sethi	%hi (ASM_PRIVATE_SYMBOL (cerror)),%g1 ;		\
+	or	%g1,%lo (ASM_PRIVATE_SYMBOL (cerror)),%g1 ;	\
+	jmpl	%g1+%g0,%g0 ;		\
+	nop ;				\
+noerr:					\
+	jmpl	%o7+8,%g0 ;		\
+	nop
+
+/* Support for reentrant syscalls.  The "struct _reent *" arg is always the
+   the first one.  After that we allow up to four additional args.  We could
+   allow more, but that's all we need for now.
+
+   It may seem inefficient to have the reent arg be the first one as it means
+   copying all the other args into place (as opposed to making the reent arg
+   the last one in which case there wouldn't be any copying).  I chose a clean
+   design over an extra four instructions in a system call.  All other
+   reentrant functions use the first arg this way.
+   ??? Of course this scheme breaks down if we need to support 6 or more args.
+
+   And of course the system calls aren't *really* reentrant.  The intent
+   is to exercise the reentrancy framework rather than provide/claim
+   real reentrancy for this port.
+*/
+
+#define defsyscall_r(name, n) \
+	TEXT_SECTION ;			\
+	ALIGN (4) ;			\
+	GLOBAL (ASM_SYMBOL (name)) ;	\
+ASM_SYMBOL (name):			\
+	mov	n,%g1 ;			\
+	mov	%o0,%o5 ;		\
+	mov	%o1,%o0 ;		\
+	mov	%o2,%o1 ;		\
+	mov	%o3,%o2 ;		\
+	mov	%o4,%o3 ;		\
+	ta	SYSCALL_TRAP ;		\
+	bcc	noerr ;			\
+	sethi	%hi (ASM_PRIVATE_SYMBOL (cerror_r)),%g1 ;	\
+	or	%g1,%lo (ASM_PRIVATE_SYMBOL (cerror_r)),%g1 ;	\
+	jmpl	%g1+%g0,%g0 ;		\
+	mov	%o5,%o1 ;		\
+noerr:					\
+	jmpl	%o7+8,%g0 ;		\
+	nop
+
+#define seterrno() \
+	sethi	%hi (ASM_PRIVATE_SYMBOL (cerror)),%g1 ;		\
+	or	%g1,%lo (ASM_PRIVATE_SYMBOL (cerror)),%g1 ;	\
+	jmpl	%g1+%g0,%g0 ;		\
+	nop
+
+#endif /* _SYSCALLASM_H_ */