First version

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@214 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 98 insertions, 0 deletions

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