[patch] Altera Nios II support

[Sandra Loosemore <sandra at codesourcery dot com>]

The attached patch adds minimal support for building newlib for Altera 
Nios II ELF (nios2-elf).  Altera did the initial toolchain port for this 
processor some years ago and now Mentor Graphics is helping to update 
the patches and get them in the upstream repositories.  The binutils 
patches were committed a couple of months ago and the gcc port has just 
been posted.  gdb will be posted soon and glibc (for nios2-linux-gnu 
target) will follow in due course.

For this target, we are not contributing a libgloss port, only newlib 
proper.  Most people developing code for bare-metal applications on Nios 
II will probably use a HAL BSP, which Altera's tools generate directly 
from the hardware description.  If the hardware description includes a 
serial interface, the HAL BSP implements the low-level system calls to 
make it work for console I/O, as well as providing all the necessary 
startup and initialization code.  In addition to testing with a HAL BSP, 
at Mentor we also have a BSP built using our own proprietary framework 
that supports semihosted I/O when used with an appropriate debug probe. 
 We re-used the same semihosting API as is implemented by the m68k 
libgloss port and we would recommend borrowing that code if there is 
future demand for a semihosted libgloss implementation on this target.

Besides running the newlib testsuite, we've also run the complete 
gcc/g++/libstdc++ and gdb testsuites using newlib on nios2-elf, so the 
newlib port has been well-tested overall.

I've elided the automatically-generated files from the attached patch to 
make it easier to review.  I also didn't include the aclocal.m4 file in 
the diff because it is an exact copy of the one from the mips directory. 
 Of course these files will be checked in with the rest of the patch 
per the ChangeLog, but I saw no point in asking maintainers to wade 
through the diffs when reviewing this patch.

OK to commit?

-Sandra

2013-04-19  Sandra Loosemore  <sandra@codesourcery.com>

	Based on patches from Altera Corporation.

	* configure.ac (noconfigdirs [nios2-*-*]): Add target-libgloss.
	* configure: Regenerated.

	newlib/
	* configure.host (machine_dir, sys_dir, syscall_dir, newlib_cflags):
	Add settings for nios2*.
	* libc/include/machine/ieeefp.h (IEEE_BIG_ENDIAN, IEEE_LITTLE_ENDIAN):
	Likewise.
	* libc/include/machine/setjmp.h (JBLEN, JBTYPE): Likewise.
	* libc/machine/configure.in: Add nios2 subdir.
	* libc/machine/configure: Regenerated.
	* libc/machine/nios2/Makefile.am: New.
	* libc/machine/nios2/Makefile.in: New (autogenerated).
	* libc/machine/nios2/aclocal.m4: New (copied from mips version).
	* libc/machine/nios2/configure.in: New.
	* libc/machine/nios2/configure: New (autogenerated).
	* libc/machine/nios2/setjmp.s: New.

Index: configure.ac
===================================================================
RCS file: /cvs/src/src/configure.ac,v
retrieving revision 1.187
diff -u -p -r1.187 configure.ac
--- configure.ac	15 Feb 2013 17:55:25 -0000	1.187
+++ configure.ac	19 Apr 2013 15:34:08 -0000
@@ -1055,6 +1055,9 @@ case "${target}" in
   mt-*-*)
     noconfigdirs="$noconfigdirs sim"
     ;;
+  nios2-*-*)
+    noconfigdirs="$noconfigdirs target-libgloss"
+    ;;
   powerpc-*-aix*)
     # copied from rs6000-*-* entry
     noconfigdirs="$noconfigdirs gprof"
Index: newlib/configure.host
===================================================================
RCS file: /cvs/src/src/newlib/configure.host,v
retrieving revision 1.127
diff -u -p -r1.127 configure.host
--- newlib/configure.host	4 Dec 2012 21:43:20 -0000	1.127
+++ newlib/configure.host	19 Apr 2013 15:34:08 -0000
@@ -227,6 +227,9 @@ case "${host_cpu}" in
   mt*)
 	machine_dir=mt
 	;;
+  nios2*)
+	machine_dir=nios2
+	;;
   or16)
 	;;
   or32)
@@ -476,6 +479,9 @@ case "${host}" in
   moxie*)
         sys_dir=
         ;;
+  nios2*)
+	sys_dir=
+	;;
   powerpcle-*-pe)
 	posix_dir=posix
 	;;
@@ -703,6 +709,10 @@ case "${host}" in
         syscall_dir=syscalls
 	default_newlib_io_long_long="yes"
         ;;
+  nios2*)
+	syscall_dir=
+	newlib_cflags="${newlib_cflags} -DHAVE_RENAME -DHAVE_SYSTEM -DMISSING_SYSCALL_NAMES"
+	;;
   powerpc*-*-eabialtivec*)
 	default_newlib_io_long_long="yes"
 	newlib_cflags="${newlib_cflags} -DMISSING_SYSCALL_NAMES"
Index: newlib/libc/include/machine/ieeefp.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/machine/ieeefp.h,v
retrieving revision 1.52
diff -u -p -r1.52 ieeefp.h
--- newlib/libc/include/machine/ieeefp.h	26 Sep 2012 20:06:47 -0000	1.52
+++ newlib/libc/include/machine/ieeefp.h	19 Apr 2013 15:34:08 -0000
@@ -388,6 +388,14 @@
 #define __SMALL_BITFIELDS	/* 16 Bit INT */
 #endif
 
+#ifdef __NIOS2__
+# ifdef __nios2_big_endian__
+#  define __IEEE_BIG_ENDIAN
+# else
+#  define __IEEE_LITTLE_ENDIAN
+# endif
+#endif
+
 #ifndef __IEEE_BIG_ENDIAN
 #ifndef __IEEE_LITTLE_ENDIAN
 #error Endianess not declared!!
Index: newlib/libc/include/machine/setjmp.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/machine/setjmp.h,v
retrieving revision 1.48
diff -u -p -r1.48 setjmp.h
--- newlib/libc/include/machine/setjmp.h	28 Feb 2013 16:42:21 -0000	1.48
+++ newlib/libc/include/machine/setjmp.h	19 Apr 2013 15:34:08 -0000
@@ -282,6 +282,24 @@ _BEGIN_STD_C
 #define _JBTYPE unsigned char
 #endif
 
+/*
+ * There are two versions of setjmp()/longjmp():
+ *   1) Compiler (gcc) built-in versions.
+ *   2) Function-call versions.
+ *
+ * The built-in versions are used most of the time.  When used, gcc replaces
+ * calls to setjmp()/longjmp() with inline assembly code.  The built-in 
+ * versions save/restore a variable number of registers.
+
+ * _JBLEN is set to 40 to be ultra-safe with the built-in versions.
+ * It only needs to be 12 for the function-call versions
+ * but this data structure is used by both versions.
+ */
+#ifdef __NIOS2__
+#define _JBLEN 40
+#define _JBTYPE unsigned long
+#endif
+
 #ifdef __RX__
 #define _JBLEN 0x44
 #endif
Index: newlib/libc/machine/configure.in
===================================================================
RCS file: /cvs/src/src/newlib/libc/machine/configure.in,v
retrieving revision 1.21
diff -u -p -r1.21 configure.in
--- newlib/libc/machine/configure.in	26 Sep 2012 20:06:47 -0000	1.21
+++ newlib/libc/machine/configure.in	19 Apr 2013 15:34:08 -0000
@@ -55,6 +55,7 @@ if test -n "${machine_dir}"; then
 	moxie) AC_CONFIG_SUBDIRS(moxie) ;;
 	mt) AC_CONFIG_SUBDIRS(mt) ;;
 	necv70) AC_CONFIG_SUBDIRS(necv70) ;;
+	nios2) AC_CONFIG_SUBDIRS(nios2) ;;
 	powerpc) AC_CONFIG_SUBDIRS(powerpc) ;;
 	rl78) AC_CONFIG_SUBDIRS(rl78) ;;
 	rx) AC_CONFIG_SUBDIRS(rx) ;;
Index: newlib/libc/machine/nios2/Makefile.am
===================================================================
RCS file: newlib/libc/machine/nios2/Makefile.am
diff -N newlib/libc/machine/nios2/Makefile.am
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ newlib/libc/machine/nios2/Makefile.am	19 Apr 2013 15:34:08 -0000
@@ -0,0 +1,16 @@
+## Process this file with automake to generate Makefile.in
+
+AUTOMAKE_OPTIONS = cygnus
+
+INCLUDES = $(NEWLIB_CFLAGS) $(CROSS_CFLAGS) $(TARGET_CFLAGS)
+
+AM_CCASFLAGS = $(INCLUDES)
+
+noinst_LIBRARIES = lib.a
+
+lib_a_SOURCES = setjmp.s
+lib_a_CCASFLAGS=$(AM_CCASFLAGS)
+lib_a_CFLAGS=$(AM_CFLAGS)
+
+ACLOCAL_AMFLAGS = -I ../../.. -I ../../../..
+CONFIG_STATUS_DEPENDENCIES = $(newlib_basedir)/configure.host
Index: newlib/libc/machine/nios2/configure.in
===================================================================
RCS file: newlib/libc/machine/nios2/configure.in
diff -N newlib/libc/machine/nios2/configure.in
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ newlib/libc/machine/nios2/configure.in	19 Apr 2013 15:34:08 -0000
@@ -0,0 +1,14 @@
+dnl This is the newlib/libc/machine/nios2 configure.in file.
+dnl Process this file with autoconf to produce a configure script.
+
+AC_PREREQ(2.59)
+AC_INIT([newlib],[NEWLIB_VERSION])
+AC_CONFIG_SRCDIR([setjmp.s])
+
+dnl Can't be done in NEWLIB_CONFIGURE because that confuses automake. 
+AC_CONFIG_AUX_DIR(../../../..)
+
+NEWLIB_CONFIGURE(../../..)
+
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
Index: newlib/libc/machine/nios2/setjmp.s
===================================================================
RCS file: newlib/libc/machine/nios2/setjmp.s
diff -N newlib/libc/machine/nios2/setjmp.s
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ newlib/libc/machine/nios2/setjmp.s	19 Apr 2013 15:34:08 -0000
@@ -0,0 +1,54 @@
+;/*
+; * C library -- _setjmp, _longjmp
+; *
+; *      _longjmp(a,v)
+; * will generate a "return(v?v:1)" from
+; * the last call to
+; *      _setjmp(a)
+; * by unwinding the call stack.
+; * The previous signal state is NOT restored.
+; */
+;
+;
+	.section	.text
+	.align	3
+	.globl	setjmp
+	.type	setjmp,@function
+	.globl	longjmp
+	.type	longjmp,@function
+
+
+setjmp:
+	stw	r16, 0(r4)
+	stw	r17, 4(r4)
+	stw	r18, 8(r4)
+	stw	r19, 12(r4)
+	stw	r20, 16(r4)
+	stw	r21, 20(r4)
+	stw	r22, 24(r4)
+	stw	r23, 28(r4)
+	stw	gp, 32(r4)
+	stw	sp, 36(r4)
+	stw	fp, 40(r4)
+	stw	ra, 44(r4)
+	mov	r2, zero
+	ret
+
+longjmp:
+	ldw	r16, 0(r4)
+	ldw	r17, 4(r4)
+	ldw	r18, 8(r4)
+	ldw	r19, 12(r4)
+	ldw	r20, 16(r4)
+	ldw	r21, 20(r4)
+	ldw	r22, 24(r4)
+	ldw	r23, 28(r4)
+	ldw	gp, 32(r4)
+	ldw	sp, 36(r4)
+	ldw	fp, 40(r4)
+	ldw	ra, 44(r4)
+	mov	r2, r5
+	bne	r2, zero, 1f
+	movi	r2, 1	
+1:
+	ret