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

[Jeff Johnston]

Kazu Hirata wrote:
> 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.

Ok, I must have miscounted the number of underscores.  Anyway, thanks for 
cleaning this up.  Patch checked in.

-- Jeff J.

> 
> #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