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authorJoel Sherrill <joel.sherrill@OARcorp.com>1995-05-11 17:39:37 +0000
committerJoel Sherrill <joel.sherrill@OARcorp.com>1995-05-11 17:39:37 +0000
commitac7d5ef06a6d6e8d84abbd1f0b82162725f98326 (patch)
tree9304cf759a73f2a1c6fd3191948f00e870af3787 /c/src/lib/start/i960
downloadrtems-ac7d5ef06a6d6e8d84abbd1f0b82162725f98326.tar.bz2
Initial revision
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+/* entry.s
+ *
+ * This file contains the entry point for the application.
+ * The name of this entry point is compiler dependent.
+ * It jumps to the BSP which is responsible for performing
+ * all initialization.
+ *
+ * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994.
+ * On-Line Applications Research Corporation (OAR).
+ * All rights assigned to U.S. Government, 1994.
+ *
+ * This material may be reproduced by or for the U.S. Government pursuant
+ * to the copyright license under the clause at DFARS 252.227-7013. This
+ * notice must appear in all copies of this file and its derivatives.
+ *
+ * $Id$
+ */
+
+#include "asm.h"
+
+ BEGIN_CODE
+ PUBLIC(start) # GNU960 default entry point
+
+start:
+ mov 3, r12
+ modpc r12, r12, r12 # enable tracing/trace faults
+ mov g5, g5 # NOP
+ mov 0, g14 # initialize constant for C
+
+ /*
+ * zero out uninitialized data area
+ */
+zerobss:
+ lda _end, r4 /* find end of .bss */
+ lda _bss_start, r5 /* find beginning of .bss */
+ ldconst 0, r6
+
+loop: st r6, (r5) /* to zero out uninitialized */
+ addo 4, r5, r5 /* data area */
+ cmpobl r5, r4, loop /* loop until _end reached */
+
+/* set up stack pointer:
+ * The heap will begin at '_end'; its length is 'heap_size'
+ * bytes. The stack will begin at the first 64-byte-aligned
+ * block after the heap.
+ *
+ * A default value of 'heap_size' is set by linking with libnindy.a
+ * The default can be overridden by redefining this symbol at link
+ * time (with a line of the form 'heap_size=XXXX;' in the lnk960
+ * linker specification file; or one of the form
+ * "-defsym heap_size=XXXX" on the gld960 invocation line).
+ */
+
+ ldconst _end, sp /* set sp = address of end of heap */
+ lda heap_size(sp),sp
+ lda 64(sp), sp /* Now round up to 64-byte boundary */
+ ldconst 0xffffffc0, r12
+ and r12, sp, sp
+ st sp, _stack_start /* Save for brk() routine */
+
+ call init_frames
+ ret /* return to monitor */
+
+init_frames:
+ mov 0, g14 /* initialize constant for C */
+ ldconst 0x3b001000, g0
+ ldconst 0x00009107, g1
+ modac g1, g0, g0 /* set AC controls */
+
+ /*
+ * remember the frame, so that we can set it up if necessary
+ */
+
+ st fp, _start_frame
+
+ /*
+ * Call application mainline.
+ * Someday, real values of argc and argv will be set up.
+ * For now, they are set to 0.
+ */
+ ldconst 0,g0
+ ldconst 0,g1
+ call _bsp_start
+ ret
+
+END_CODE
+
+ BEGIN_DATA
+
+ PUBLIC(_start_frame)
+SYM (_start_frame):
+ .word 0 # addr of first user frame: for gdb960
+
+SYM (_stack_start):
+ PUBLIC(_stack_start)
+ .word 0 # addr of first user frame: for gdb960
+
+END_DATA
+
+BEGIN_BSS
+ PUBLIC(heap_size)
+ .set heap_size,0x2000
+END_BSS
+
+END