| [444] | 1 | .text |
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| 2 | .balign 4 |
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| 3 | .global _start |
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| 4 | _start: |
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| 5 | |
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| 6 | seth sp, #shigh(_stack) |
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| 7 | add3 sp, sp, #low(_stack) |
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| 8 | ldi fp, #0 |
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| 9 | |
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| 10 | # Clear the BSS. Do it in two parts for efficiency: longwords first |
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| 11 | # for most of it, then the remaining 0 to 3 bytes. |
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| 12 | |
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| 13 | seth r2, #shigh(__bss_start) |
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| 14 | add3 r2, r2, #low(__bss_start); R2 = start of BSS |
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| 15 | seth r3, #shigh(_end) |
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| 16 | add3 r3, r3, #low(_end) ; R3 = end of BSS + 1 |
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| 17 | |
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| 18 | sub r3, r2 ; R3 = BSS size in bytes |
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| 19 | mv r4, r3 |
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| 20 | srli r4, #2 ; R4 = BSS size in longwords (rounded down) |
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| 21 | ldi r1, #0 ; clear R1 for longword store |
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| 22 | addi r2, #-4 ; account for pre-inc store |
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| 23 | beqz r4, .Lendloop1 ; any more to go? |
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| 24 | .Lloop1: |
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| 25 | st r1, @+r2 ; yep, zero out another longword |
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| 26 | addi r4, #-1 ; decrement count |
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| 27 | bnez r4, .Lloop1 ; go do some more |
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| 28 | .Lendloop1: |
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| 29 | and3 r4, r3, #3 ; get no. of remaining BSS bytes to clear |
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| 30 | addi r2, #4 ; account for pre-inc store |
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| 31 | beqz r4, .Lendloop2 ; any more to go? |
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| 32 | .Lloop2: |
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| 33 | stb r1, @r2 ; yep, zero out another byte |
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| 34 | addi r2, #1 ; bump address |
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| 35 | addi r4, #-1 ; decrement count |
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| 36 | bnez r4, .Lloop2 ; go do some more |
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| 37 | .Lendloop2: |
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| 38 | |
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| 39 | # Run code in the .init section. |
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| 40 | # This will queue the .fini section to be run with atexit. |
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| 41 | |
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| 42 | bl __init |
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| 43 | |
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| 44 | # Call main, then exit. |
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| 45 | |
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| 46 | bl main |
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| 47 | bl exit |
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| 48 | |
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| 49 | # If that fails just loop. |
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| 50 | |
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| 51 | .Lexit: |
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| 52 | bra .Lexit |
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