1 | /* |
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2 | * $Id$ |
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3 | * |
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4 | * Re-written the gen68302 start-up code. |
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5 | * |
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6 | * Uses gas syntax only, removed the OAR asm.h. |
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7 | * |
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8 | * Supplies a complete vector table in ROM. |
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9 | * |
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10 | * Manages all vectors with seperate handlers to trap unhandled |
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11 | * execptions. |
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12 | * |
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13 | * Uses the target specific header file to get the runtime |
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14 | * configuration |
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15 | * |
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16 | * COPYRIGHT (c) 1996 |
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17 | * Objective Design Systems Pty Ltd (ODS) |
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18 | * |
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19 | * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. |
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20 | * On-Line Applications Research Corporation (OAR). |
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21 | * All rights assigned to U.S. Government, 1994. |
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22 | * |
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23 | * This material may be reproduced by or for the U.S. Government pursuant |
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24 | * to the copyright license under the clause at DFARS 252.227-7013. This |
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25 | * notice must appear in all copies of this file and its derivatives. |
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26 | * |
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27 | */ |
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28 | |
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29 | | |
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30 | | Entry from debugger |
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31 | | |
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32 | .sect .text |
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33 | |
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34 | | |
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35 | | Start |
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36 | | |
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37 | | Entered from a hardware reset. |
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38 | | |
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39 | |
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40 | .global start | Default entry point for GNU |
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41 | start: |
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42 | |
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43 | move.w #0x2700,%sr | Disable all interrupts |
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44 | |
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45 | | |
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46 | | zero out uninitialized data area |
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47 | | |
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48 | |
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49 | zerobss: |
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50 | moveal #end,%a0 | find end of .bss |
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51 | moveal #bss_start,%a1 | find beginning of .bss |
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52 | moveq #0,%d0 |
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53 | |
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54 | zerobss_loop: |
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55 | |
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56 | movel %d0,%a1@+ | to zero out uninitialized |
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57 | cmpal %a0,%a1 |
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58 | jlt zerobss_loop | loop until _end reached |
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59 | |
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60 | movel #end,%d0 | d0 = end of bss/start of heap |
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61 | addl #heap_size,%d0 | d0 = end of heap |
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62 | |
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63 | movel %d0,stack_start | Save for brk() routine |
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64 | addl #stack_size,%d0 | make room for stack |
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65 | andl #0xffffffc0,%d0 | align it on 16 byte boundary |
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66 | |
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67 | movw #0x3700,%sr | SUPV MODE,INTERRUPTS OFF!!! |
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68 | movel %d0,%a7 | set master stack pointer |
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69 | movel %d0,%a6 | set base pointer |
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70 | |
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71 | jsr boot_phase_3 |
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72 | |
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73 | | |
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74 | | Initialised data |
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75 | | |
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76 | |
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77 | .sect .data |
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78 | |
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79 | .global start_frame |
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80 | |
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81 | start_frame: |
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82 | .space 4,0 |
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83 | |
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84 | .global stack_start |
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85 | |
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86 | stack_start: |
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87 | .space 4,0 |
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88 | |
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89 | | |
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90 | | Uninitialised data |
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91 | | |
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92 | |
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93 | .sect .bss |
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94 | |
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95 | .global environ |
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96 | .align 2 |
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97 | |
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98 | environ: |
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99 | .long 0 |
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100 | |
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101 | .global heap_size |
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102 | .set heap_size,0x2000 |
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103 | |
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104 | .global stack_size |
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105 | .set stack_size,0x1000 |
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106 | |
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107 | |
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