| 1 | .text |
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| 2 | .global _start |
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| 3 | .type _start,@function |
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| 4 | .stabs "crt0.S",100,0,0,_start |
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| 5 | .stabs "int:t(0,1)=r(0,1);-32768;32767;",128,0,0,0 |
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| 6 | .stabs "_start:F(0,1)",36,0,1,_start |
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| 7 | |
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| 8 | _start: |
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| 9 | |
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| 10 | ; R14 always contains memory base address (0) |
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| 11 | |
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| 12 | ldi r14,0 |
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| 13 | |
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| 14 | ; Set the USER and SYSTEM stack pointers. |
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| 15 | |
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| 16 | ldi r0, 0 ; zero arguments |
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| 17 | ldi r1, 0 |
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| 18 | mvtc r0, psw ; select SPI and set it |
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| 19 | ldi sp, _stack |
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| 20 | ldi r10, 0x8000 ; select SPU/FP and set it |
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| 21 | mvtc r10, psw || ldi r11, 0; clear stack frame |
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| 22 | ldi sp, _stack - 0x200 |
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| 23 | ldi r13, 0 |
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| 24 | |
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| 25 | ; Clear the BSS. Do it in two parts for efficiency: longwords first |
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| 26 | ; for most of it, then the remaining 0 to 3 bytes. |
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| 27 | |
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| 28 | ldi r2, __bss_start ; R2 = start of BSS |
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| 29 | ldi r3, _end ; R3 = end of BSS + 1 |
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| 30 | sub r3, r2 ; R3 = BSS size in bytes |
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| 31 | mv r4, r3 |
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| 32 | srli r4, 2 ; R4 = BSS size in longwords (rounded down) |
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| 33 | loop1: |
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| 34 | cmpeqi r4, 0 ; more longords to zero out? |
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| 35 | brf0t.s endloop1 ; nope |
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| 36 | st2w r0, @r2+ ; yep, zero out another longword |
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| 37 | subi r4, 1 ; decrement count |
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| 38 | bra.l loop1 ; go do some more |
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| 39 | |
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| 40 | endloop1: |
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| 41 | and3 r4, r3, 3 ; get no. of remaining BSS bytes to clear |
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| 42 | loop2: |
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| 43 | cmpeqi r4, 0 ; more bytes to zero out? |
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| 44 | brf0t.s endloop2 ; nope |
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| 45 | stb r0, @r2 ; yep, zero out another byte |
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| 46 | addi r2, 1 ; bump address |
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| 47 | subi r4, 1 ; decrement count |
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| 48 | bra.s loop2 ; go do some more |
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| 49 | endloop2: |
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| 50 | ; Call main, then stop simulator |
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| 51 | st r11, @-sp |
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| 52 | st r13, @-sp |
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| 53 | mv r11, sp |
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| 54 | |
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| 55 | bl main |
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| 56 | bl exit |
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| 57 | stop |
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| 58 | .Lstart: |
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| 59 | .size _start,.Lstart-_start |
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| 60 | .stabs "",36,0,0,.Lstart-_start |
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| 61 | |
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| 62 | .section .stack |
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| 63 | _stack: .long 1 |
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