1 | /* entry.s |
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2 | * |
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3 | * This file contains the entry point for the application. |
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4 | * The name of this entry point is compiler dependent. |
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5 | * It jumps to the BSP which is responsible for performing |
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6 | * all initialization. |
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7 | * |
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8 | * COPYRIGHT (c) 1989-1997. |
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9 | * On-Line Applications Research Corporation (OAR). |
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10 | * Copyright assigned to U.S. Government, 1994. |
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11 | * |
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12 | * The license and distribution terms for this file may be |
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13 | * found in the file LICENSE in this distribution or at |
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14 | * http://www.OARcorp.com/rtems/license.html. |
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15 | * |
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16 | * $Id$ |
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17 | */ |
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18 | |
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19 | #include "asm.h" |
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20 | |
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21 | BEGIN_CODE |
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22 | PUBLIC(start) # GNU960 default entry point |
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23 | |
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24 | SYM(start): |
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25 | mov 3, r12 |
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26 | modpc r12, r12, r12 # enable tracing/trace faults |
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27 | mov g5, g5 # NOP |
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28 | mov 0, g14 # initialize constant for C |
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29 | |
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30 | /* |
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31 | * zero out uninitialized data area |
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32 | */ |
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33 | zerobss: |
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34 | lda _end, r4 /* find end of .bss */ |
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35 | lda _bss_start, r5 /* find beginning of .bss */ |
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36 | ldconst 0, r6 |
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37 | |
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38 | loop: st r6, (r5) /* to zero out uninitialized */ |
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39 | addo 4, r5, r5 /* data area */ |
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40 | cmpobl r5, r4, loop /* loop until _end reached */ |
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41 | |
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42 | /* set up stack pointer: |
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43 | * The heap will begin at '_end'; its length is 'heap_size' |
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44 | * bytes. The stack will begin at the first 64-byte-aligned |
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45 | * block after the heap. |
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46 | * |
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47 | * A default value of 'heap_size' is set by linking with libnindy.a |
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48 | * The default can be overridden by redefining this symbol at link |
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49 | * time (with a line of the form 'heap_size=XXXX;' in the lnk960 |
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50 | * linker specification file; or one of the form |
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51 | * "-defsym heap_size=XXXX" on the gld960 invocation line). |
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52 | */ |
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53 | |
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54 | ldconst _end, sp /* set sp = address of end of heap */ |
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55 | lda heap_size(sp),sp |
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56 | lda 64(sp), sp /* Now round up to 64-byte boundary */ |
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57 | ldconst 0xffffffc0, r12 |
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58 | and r12, sp, sp |
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59 | st sp, _stack_start /* Save for brk() routine */ |
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60 | |
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61 | call init_frames |
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62 | ret /* return to monitor */ |
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63 | |
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64 | init_frames: |
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65 | mov 0, g14 /* initialize constant for C */ |
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66 | ldconst 0x3b001000, g0 |
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67 | ldconst 0x00009107, g1 |
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68 | modac g1, g0, g0 /* set AC controls */ |
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69 | |
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70 | /* |
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71 | * remember the frame, so that we can set it up if necessary |
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72 | */ |
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73 | |
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74 | st fp, _start_frame |
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75 | |
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76 | /* |
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77 | * Call application mainline. |
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78 | * Someday, real values of argc and argv will be set up. |
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79 | * For now, they are set to 0. |
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80 | */ |
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81 | ldconst 0,g0 |
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82 | ldconst 0,g1 |
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83 | ldconst 0,g2 |
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84 | call _main |
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85 | ret |
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86 | |
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87 | END_CODE |
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88 | |
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89 | BEGIN_DATA |
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90 | |
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91 | PUBLIC(_start_frame) |
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92 | PUBLIC(start_frame) |
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93 | SYM (_start_frame): |
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94 | SYM (start_frame): |
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95 | .word 0 # addr of first user frame: for gdb960 |
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96 | |
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97 | PUBLIC(_stack_start) |
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98 | PUBLIC(stack_start) |
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99 | SYM (_stack_start): |
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100 | SYM (stack_start): |
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101 | .word 0 # addr of first user frame: for gdb960 |
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102 | |
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103 | END_DATA |
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104 | |
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105 | BEGIN_BSS |
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106 | PUBLIC(heap_size) |
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107 | .set heap_size,0x2000 |
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108 | END_BSS |
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109 | |
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110 | END |
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