[patch] Rewrite libc/sys/h8300hms/_exit.c in assembly.

[Kazu Hirata]

Hi Jeff,

> I have one concern with your patch.  It appears that C functions
> map to names prepended by _ on h8300hms.  For example, the C library
> refers to _read, but it is defined in assembly as __read in read.S.
> If you supply _exit() in assembly that may override C's exit()
> function which among other things, runs the atexit() list.  In the
> old C code, the __exit() routine should have been extraneous.
> Please try taking out _exit in your assembly code _exit.S and trying
> to link a simple application which sets up an atexit() function and
> exits with a non-zero return code.  It should link with the __exit
> routine in your assembly code and run the atexit() list
> successfully.

My original patch does not override exit() (in C sense) because all I
have there are __exit and ___exit (in asm sense).  Anyway, I removed
the unnecessary function ___exit (in asm sense) and tested the
following code.

#include <stdlib.h>
#include <stdio.h>

void
bar (void)
{
  printf ("Hello, world\n");
}

int
main (void)
{
  atexit (bar);
  exit (0);
}

Built newlib with GCC from the tree-ssa branch.  OK to apply?

2004-03-11  Kazu Hirata  <kazu@cs.umass.edu>

	* libc/sys/h8300hms/Makefile.am (lib_a_SOURCES): Replace
	_exit.c with _exit.S.
	* libc/sys/h8300hms/Makefile.in: Regenerate.
	* libc/sys/h8300hms/_exit.c: Remove.
	* libc/sys/h8300hms/_exit.S: New.

Index: Makefile.am
===================================================================
RCS file: /cvs/src/src/newlib/libc/sys/h8300hms/Makefile.am,v
retrieving revision 1.3
diff -u -r1.3 Makefile.am
--- Makefile.am	25 Feb 2003 20:36:29 -0000	1.3
+++ Makefile.am	11 Mar 2004 04:59:43 -0000
@@ -6,7 +6,7 @@
 
 noinst_LIBRARIES = lib.a
 
-lib_a_SOURCES = syscalls.c _exit.c sbrk.c misc.c crt1.c \
+lib_a_SOURCES = syscalls.c _exit.S sbrk.c misc.c crt1.c \
 	close.S fstat.S lseek.S open.S read.S stat.S write.S
 
 all: crt0.o
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/newlib/libc/sys/h8300hms/Makefile.in,v
retrieving revision 1.8
diff -u -r1.8 Makefile.in
--- Makefile.in	23 Jan 2004 21:37:38 -0000	1.8
+++ Makefile.in	11 Mar 2004 04:59:43 -0000
@@ -89,7 +89,8 @@
 
 noinst_LIBRARIES = lib.a
 
-lib_a_SOURCES = syscalls.c _exit.c sbrk.c misc.c crt1.c 	close.S fstat.S lseek.S open.S read.S stat.S write.S
+lib_a_SOURCES = syscalls.c _exit.S sbrk.c misc.c crt1.c \
+	close.S fstat.S lseek.S open.S read.S stat.S write.S
 
 
 ACLOCAL_AMFLAGS = -I ../../..
Index: _exit.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/sys/h8300hms/_exit.c,v
retrieving revision 1.2
diff -u -r1.2 _exit.c
--- _exit.c	31 Jan 2003 20:44:26 -0000	1.2
+++ _exit.c	11 Mar 2004 04:59:43 -0000
@@ -1,36 +0,1 @@
-/* FIXME: which one? */
-
-#include <_ansi.h>
-
-/* `sleep' is passed an argument in r0 that indicates the reason
-   the program is exiting.  The format of r0 is defined in devo/include/wait.h.
-*/
-
-void
-_DEFUN (_exit,(rc),
-     int rc)
-{
-  short rc2;
-
-  rc2 = 0xdead;
-  asm("mov.w %0,r1" : : "r" (rc2) : "r1");
-  rc2 = 0xbeef;
-  asm("mov.w %0,r2" : : "r" (rc2) : "r2");
-  rc2 = rc << 8;
-  asm("mov.w %0,r0\n\tsleep" : : "r" (rc2) : "r0");
-}
-
-void
-_DEFUN (__exit,(rc),
-     int rc)
-{
-  short rc2;
-
-  rc2 = 0xdead;
-  asm("mov.w %0,r1" : : "r" (rc2) : "r1");
-  rc2 = 0xbeef;
-  asm("mov.w %0,r2" : : "r" (rc2) : "r2");
-  rc2 = rc << 8;
-  asm("mov.w %0,r0\n\tsleep" : : "r" (rc2) : "r0");
-}
--- /dev/null	2003-09-15 09:40:47.000000000 -0400
+++ _exit.S	2004-03-10 23:36:30.173398682 -0500
@@ -0,0 +1,17 @@
+#include "setarch.h"
+
+/* `sleep' is passed an argument in r0 that indicates the reason
+   the program is exiting.  The format of r0 is defined in devo/include/wait.h.
+*/
+
+/* extern void _exit (int rc); */
+
+	.section .text
+	.align 2
+	.global __exit
+__exit:
+	mov.w	#0xdead,r1
+	mov.w	#0xbeef,r2
+	mov.b	r0l,r0h
+	sub.b	r0l,r0l
+	sleep