XScale version of setjmp

[Ian Lance Taylor <ian at wasabisystems dot com>]

When configuring newlib for xscale-elf, setjmp used to come from
libc/sys/arm/setjmp.S.  However, with this patch:

2004-06-09  Toralf Lund  <toralf@procaptura.com>

	* libc/sys/arm/setjmp.S, libc/sys/arm/access.c: Move
	files from libc/sys/arm to libc/machine/arm.

that file was moved to libc/machine/arm.  With that change, there is
no longer any setjmp for xscaleelf.

This patch takes the simple approach of adding
libc/machine/xscale/setjmp.S.

OK to commit?

Ian

2004-09-21  Ian Lance Taylor  <ian@wasabisystems.com>

	* libc/machine/xscale/setjmp.S: New file, copied from
	libc/machine/arm/setjmp.S.
	* libc/machine/xscale/Makefile.am (lib_a_SOURCES): Add setjmp.S.
	* libc/machine/xscale/Makefile.in: Regenerate.

Index: Makefile.am
===================================================================
RCS file: /cvs/src/src/newlib/libc/machine/xscale/Makefile.am,v
retrieving revision 1.1
diff -u -r1.1 Makefile.am
--- Makefile.am	30 Nov 2000 01:57:26 -0000	1.1
+++ Makefile.am	21 Sep 2004 17:13:30 -0000
@@ -8,7 +8,7 @@
 
 lib_a_SOURCES = \
 	memchr.c memcmp.c memcpy.c memmove.c memset.c \
-	strchr.c strcmp.c strcpy.c strlen.c
+	strchr.c strcmp.c strcpy.c strlen.c setjmp.S
 
 ACLOCAL_AMFLAGS = -I ../../..
 CONFIG_STATUS_DEPENDENCIES = $(newlib_basedir)/configure.host
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/newlib/libc/machine/xscale/Makefile.in,v
retrieving revision 1.6
diff -u -r1.6 Makefile.in
--- Makefile.in	23 Jan 2004 21:37:34 -0000	1.6
+++ Makefile.in	21 Sep 2004 17:13:30 -0000
@@ -89,7 +89,9 @@
 
 noinst_LIBRARIES = lib.a
 
-lib_a_SOURCES =  	memchr.c memcmp.c memcpy.c memmove.c memset.c 	strchr.c strcmp.c strcpy.c strlen.c
+lib_a_SOURCES = \
+	memchr.c memcmp.c memcpy.c memmove.c memset.c \
+	strchr.c strcmp.c strcpy.c strlen.c setjmp.S
 
 
 ACLOCAL_AMFLAGS = -I ../../..
@@ -105,7 +107,7 @@
 LIBS = @LIBS@
 lib_a_LIBADD = 
 lib_a_OBJECTS =  memchr.o memcmp.o memcpy.o memmove.o memset.o strchr.o \
-strcmp.o strcpy.o strlen.o
+strcmp.o strcpy.o strlen.o setjmp.o
 CFLAGS = @CFLAGS@
 COMPILE = $(CC) $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
 CCLD = $(CC)
Index: setjmp.S
===================================================================
RCS file: setjmp.S
diff -N setjmp.S
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ setjmp.S	21 Sep 2004 17:13:30 -0000
@@ -0,0 +1,137 @@
+/* This is a simple version of setjmp and longjmp.
+
+   Nick Clifton, Cygnus Solutions, 13 June 1997.  */
+
+/* ANSI concatenation macros.  */
+#define CONCAT(a, b)  CONCAT2(a, b)
+#define CONCAT2(a, b) a##b
+
+#ifndef __USER_LABEL_PREFIX__
+#error  __USER_LABEL_PREFIX__ not defined
+#endif
+
+#define SYM(x) CONCAT (__USER_LABEL_PREFIX__, x)
+
+#ifdef __ELF__
+#define TYPE(x) .type SYM(x),function
+#define SIZE(x) .size SYM(x), . - SYM(x)
+#else
+#define TYPE(x)
+#define SIZE(x)
+#endif
+
+/* Arm/Thumb interworking support:
+
+   The interworking scheme expects functions to use a BX instruction
+   to return control to their parent.  Since we need this code to work
+   in both interworked and non-interworked environments as well as with
+   older processors which do not have the BX instruction we do the 
+   following:
+	Test the return address.
+	If the bottom bit is clear perform an "old style" function exit.
+	(We know that we are in ARM mode and returning to an ARM mode caller).
+	Otherwise use the BX instruction to perform the function exit.
+
+   We know that we will never attempt to perform the BX instruction on 
+   an older processor, because that kind of processor will never be 
+   interworked, and a return address with the bottom bit set will never 
+   be generated.
+
+   In addition, we do not actually assemble the BX instruction as this would
+   require us to tell the assembler that the processor is an ARM7TDMI and
+   it would store this information in the binary.  We want this binary to be
+   able to be linked with binaries compiled for older processors however, so
+   we do not want such information stored there.  
+
+   If we are running using the APCS-26 convention however, then we never
+   test the bottom bit, because this is part of the processor status.  
+   Instead we just do a normal return, since we know that we cannot be 
+   returning to a Thumb caller - the Thumb does not support APCS-26.
+	
+   Function entry is much simpler.  If we are compiling for the Thumb we 
+   just switch into ARM mode and then drop through into the rest of the
+   function.  The function exit code will take care of the restore to
+   Thumb mode.  */
+
+#ifdef __APCS_26__
+#define RET	movs		pc, lr
+#else
+#define RET	tst		lr, #1; \
+	        moveq		pc, lr ; \
+.word           0xe12fff1e	/* bx lr */
+#endif
+
+#ifdef __thumb__
+#define	MODE		.thumb_func
+.macro PROLOGUE name
+	.code 16
+	bx	pc
+	nop	
+	.code 32
+SYM (.arm_start_of.\name):
+.endm
+#else
+#define	MODE		.code 32
+.macro PROLOGUE name
+.endm
+#endif
+	
+.macro FUNC_START name
+	.text
+	.align 2
+	MODE
+	.globl SYM (\name)
+	TYPE (\name)
+SYM (\name):
+	PROLOGUE \name
+.endm
+
+.macro FUNC_END name
+	RET
+	SIZE (\name)
+.endm
+	
+/* --------------------------------------------------------------------
+                 int setjmp (jmp_buf); 
+   -------------------------------------------------------------------- */
+	
+	FUNC_START setjmp
+
+	/* Save all the callee-preserved registers into the jump buffer.  */
+	stmea		a1!, { v1-v7, fp, ip, sp, lr }
+	
+#if 0	/* Simulator does not cope with FP instructions yet.  */
+#ifndef __SOFTFP__
+	/* Save the floating point registers.  */
+	sfmea		f4, 4, [a1]
+#endif
+#endif		
+	/* When setting up the jump buffer return 0.  */
+	mov		a1, #0
+
+	FUNC_END setjmp
+	
+/* --------------------------------------------------------------------
+		volatile void longjmp (jmp_buf, int);
+   -------------------------------------------------------------------- */
+	
+	FUNC_START longjmp
+
+	/* If we have stack extension code it ought to be handled here.  */
+	
+	/* Restore the registers, retrieving the state when setjmp() was called.  */
+	ldmfd		a1!, { v1-v7, fp, ip, sp, lr }
+	
+#if 0	/* Simulator does not cope with FP instructions yet.  */
+#ifndef __SOFTFP__
+	/* Restore floating point registers as well.  */
+	lfmfd		f4, 4, [a1]
+#endif
+#endif	
+	/* Put the return value into the integer result register.
+	   But if it is zero then return 1 instead.  */	
+	movs		a1, a2
+	moveq		a1, #1
+
+	FUNC_END longjmp
+