Revert - this was a bit premature.

1 files changed, 65 insertions, 24 deletions

diff --git a/lib/csu/m88k/crt0.c b/lib/csu/m88k/crt0.c
index f87274a2692..ac4e2a0f72e 100644
--- a/lib/csu/m88k/crt0.c
+++ b/lib/csu/m88k/crt0.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: crt0.c,v 1.4 2003/12/25 23:26:09 miod Exp $	*/
+/*	$OpenBSD: crt0.c,v 1.5 2003/12/26 00:04:23 miod Exp $	*/
 
 /*   
  *   Mach Operating System
@@ -28,40 +28,80 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: crt0.c,v 1.4 2003/12/25 23:26:09 miod Exp $";
+static char rcsid[] = "$OpenBSD: crt0.c,v 1.5 2003/12/26 00:04:23 miod Exp $";
 #endif /* LIBC_SCCS and not lint */
 
+/* 
+ *   Author :   Jeffrey Friedl
+ *   Created:   July 1992
+ *   Standalone crt0.
+ */
+
+/*
+ * GCCisms used:
+ * 	A "volatile void fcn()" is one that never returns.
+ *	register var asm("r1"): variable VAR is raw access to named register.
+ */
+
 /*
- * When a program starts, r31 points to a structure passed from the kernel.
+ * When a program begins, r31 points to info passed from the kernel.
+ *
+ * The following shows the memory to which r31 points (think "int *r31;"),
+ * and how we derive argc, argv, and envp from that:
  *
- * This structure contains argc, the argv[] array, a NULL marker, then
- * the envp[] array, and another NULL marker.
+ *    +-------------------+ <-------------------------------------- r31
+ *    | ARGC		  | <- argc = r31[0];
+ *    +-------------------+ <- argv = &r31[1];
+ *    | &(argument #1)    |
+ *    +-------------------+
+ *    | &(argument #2)    |
+ *     -  - - - - - - -  - 
+ *    | &(argument #ARGC) |
+ *    +-------------------+
+ *    | 0x00000000	  | <- end-of-ARGV-list marker (redundant information).
+ *    +-------------------+ <- environ = envp =  &argv[argc+1];
+ *    | &(env. var. #1)   |
+ *    +-------------------+
+ *    | &(env. var. #2)   |
+ *     -  - - - - - - -  - 
+ *    | &(env. var. #N)   |
+ *    +-------------------+
+ *    | 0x00000000	  | <- end-of-ENVP-list marker (not redundant!).
+ *    +-------------------+
+ *
+ * We use 'start:' to grab r31 and call real_start(argc, argv, envp).
+ * We must do this since the function prologue makes finding the initial
+ * r31 difficult in C.
  */
 
 #include <stdlib.h>
 
 #include "common.h"
 
-extern void start(void) __asm__("start");
-
-void
-start(void)
-{
-	struct kframe {
-		int	argc;
-		char	*argv[0];
-	};
+asm("	    text		");
+asm("	    align  4		");
+asm("start: global start	");
+asm("       ld     r2, r31,   0 "); /* First arg to real_start: argc */
+asm("       addu   r3, r31,   4 "); /* Second arg to real_start: argv */
+asm("       lda    r4,  r3  [r2]"); /* Third arg to real_start: envp, but.... */
+asm("       addu   r4,  r4,   4 "); /*   ... don't forget to skip past marker */
+asm("       br.n   ___crt0_real_start");
+asm("       subu   r31, r31, 32 ");
 
-	struct kframe *kfp;
-	char **argv, *ap, *s;
+#ifdef DYNAMIC
+extern struct _dynamic	_DYNAMIC;
+struct _dynamic	*___pdynamic = &_DYNAMIC;
+#endif
 
-	/*
-	 * Pick the arguments frame as early as possible
-	 */
-	__asm__ __volatile__ ("or %0, r31, 0" : "=r" (kfp) :: "r31");
+/* static */ void volatile
+__crt0_real_start(int argc, char *argv[], char *envp[])
+{
+	register char *ap;
+	volatile int a = 0;
+	extern int end;
+	char *s;
 
-	argv = &kfp->argv[0];
-	environ = argv + kfp->argc + 1;
+	environ = envp; /* environ is for the user that can't get at 'envp' */
 
 	if (ap = argv[0]) {
 		if ((__progname = _strrchr(ap, '/')) == NULL)
@@ -74,9 +114,10 @@ start(void)
 		*s = '\0';
 		__progname = __progname_storage;
 	}
-
 asm ("__callmain:");		/* Defined for the benefit of debuggers */
-	exit(main(kfp->argc, argv, environ));
+	exit(main(argc, argv, environ));
+
+    /*NOTREACHED*/
 }
 
 #include "common.c"