From d6779f8ca4430566141c30b9459015805ef0b349 Mon Sep 17 00:00:00 2001
From: Linus Nielsen Feltzing <linus@haxx.se>
Date: Wed, 24 Apr 2002 21:46:01 +0000
Subject: First version

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@214 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/crt0.S | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 firmware/crt0.S

(limited to 'firmware')

diff --git a/firmware/crt0.S b/firmware/crt0.S
new file mode 100644
index 0000000000..785f405721
--- /dev/null
+++ b/firmware/crt0.S
@@ -0,0 +1,98 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2002 by Linus Nielsen Feltzing
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+	.section .text
+	.global	start
+start:
+	/* We begin with some tricks. If we have built our code to be loaded
+	 * via the standalone GDB stub, we will have out VBR at some other
+	 * location than 0x9000000. We must copy the trap vectors for the
+	 * GDB stub to our vector table.
+	 * If, on the other hand, we are running standalone we will have
+	 * the VBR at 0x9000000, and the copy will not do any harm.
+	 */
+	mov.l	vbr_k,r1	
+	mov.l	orig_vbr_k,r2
+	
+	/* Move the serial Rx interrupt vector */
+	mov	#0x69,r0
+	shll2	r0
+	mov.l	@(r0,r2),r3
+	mov.l	r3,@(r0,r1)
+
+	/* Move the breakpoint trap vector as well (32) */
+	mov	#0x20,r0
+	shll2	r0
+	mov.l	@(r0,r2),r3
+	mov.l	r3,@(r0,r1)
+	
+	/* Move the single step trap vector as well (127) */
+	mov	#0x7f,r0
+	shll2	r0
+	mov.l	@(r0,r2),r3
+	mov.l	r3,@(r0,r1)
+	
+	ldc	r1,vbr
+
+	/* Now let's get on with the normal business */
+	mov.l	stack_k,r15
+
+	/* zero out bss */
+	mov.l	edata_k,r0
+	mov.l	end_k,r1
+	mov	#0,r2
+start_l:
+	mov.l	r2,@r0
+	add	#4,r0
+	cmp/ge	r0,r1
+	bt	start_l
+	nop
+
+	! call the mainline	
+	mov.l	main_k,r0
+	jsr	@r0
+	nop
+.hoo:
+    bra .hoo
+
+	.align 2
+stack_k:
+	.long	_stack	
+edata_k:
+	.long	_edata
+end_k:
+	.long	_end
+main_k:
+	.long	_main
+vbr_k:
+	.long	vectors
+orig_vbr_k:
+	.long 0x9000000
+
+#ifdef __ELF__
+	.section .stack,"aw"
+#else
+	.section .stack
+#endif
+
+	.section .vectors
+vectors:
+	.long start
+	.long _stack
+	.long start
+	.long _stack
-- 
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