| Rev | Line | |
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| [7] | 1 | /********************************************************************************* |
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| 2 | * File : reset.s |
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| 3 | * Author : Alain Greiner |
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| 4 | * Date : 28/08/2006 |
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| 5 | ********************************************************************************* |
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| 6 | * This is a minimal boot code : |
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| 7 | * - It initializes the Status Register (SR) |
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| 8 | * - It defines the stack size and initializes the stack pointer ($29) |
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| 9 | * - It initializes the global pointer ($28) that is used by GCC to |
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| 10 | * optimize acces to the global variables. |
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| 11 | * - It initializes the EPC register, and jump to the main address |
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| 12 | *********************************************************************************/ |
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| 13 | |
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| 14 | .section .reset,"ax",@progbits |
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| 15 | |
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| 16 | .extern seg_stack_base |
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| 17 | .extern seg_data_base |
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| 18 | .extern main |
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| 19 | |
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| 20 | .globl reset /* makes reset an external symbol */ |
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| 21 | .ent reset |
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| 22 | .func reset |
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| 23 | .align 2 |
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| 24 | |
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| 25 | reset: |
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| 26 | .set noreorder |
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| 27 | |
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| 28 | /* initializes SR register */ |
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| 29 | li $26, 0x00000013 |
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| 30 | mtc0 $26, $12 |
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| 31 | |
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| 32 | /* initializes stack pointer */ |
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| 33 | la $29, seg_stack_base |
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| 34 | addiu $29, $29, 0x4000 |
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| 35 | |
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| 36 | /* initializes global pointer */ |
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| 37 | la $28, seg_data_base |
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| 38 | |
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| 39 | /* jump to main in kernel mode */ |
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| 40 | la $26, main |
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| 41 | mtc0 $26, $14 |
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| 42 | eret |
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| 43 | |
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| 44 | .end reset |
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| 45 | .size reset, .-reset |
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| 46 | |
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| 47 | .set reorder |
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| 48 | |
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