1 | ##============================================================================== |
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2 | ## |
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3 | ## crt0.S |
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4 | ## |
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5 | ## MN10200 startup code |
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6 | ## |
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7 | ##============================================================================== |
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8 | ## |
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9 | ## Copyright (c) 1995, 1996, 1997, 1998 Cygnus Solutions |
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10 | ## |
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11 | ## The authors hereby grant permission to use, copy, modify, distribute, |
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12 | ## and license this software and its documentation for any purpose, provided |
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13 | ## that existing copyright notices are retained in all copies and that this |
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14 | ## notice is included verbatim in any distributions. No written agreement, |
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15 | ## license, or royalty fee is required for any of the authorized uses. |
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16 | ## Modifications to this software may be copyrighted by their authors |
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17 | ## and need not follow the licensing terms described here, provided that |
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18 | ## the new terms are clearly indicated on the first page of each file where |
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19 | ## they apply. |
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20 | ## |
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21 | |
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22 | ##------------------------------------------------------------------------------ |
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23 | |
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24 | .file "crt0.S" |
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25 | |
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26 | ##------------------------------------------------------------------------------ |
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27 | ## Startup code |
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28 | .section .text |
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29 | .global _start |
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30 | _start: |
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31 | mov _stack,a3 # Load up the stack pointer and allocate |
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32 | # our current frame. |
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33 | |
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34 | mov _edata,a0 # Get the start/end of bss |
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35 | mov _end,a1 |
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36 | |
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37 | cmp a0,a1 # If no bss, then do nothing |
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38 | beqx .L0 |
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39 | |
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40 | sub d0,d0 # clear d0 |
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41 | |
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42 | .L1: |
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43 | movb d0,(a0) # Clear a byte and bump pointer |
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44 | add 1,a0 |
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45 | cmp a0,a1 |
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46 | bnex .L1 |
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47 | |
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48 | .L0: |
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49 | jsr ___main |
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50 | sub d0,d0 |
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51 | mov d0,d1 |
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52 | mov d0,(a3) |
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53 | jsr _main # Call main program |
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54 | jmp _exit # All done, no need to return or |
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55 | # deallocate our stack. |
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56 | |
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57 | .section .stack |
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58 | _stack: .long 1 |
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