| .text |
| .balign 4 |
| .global _start |
| _start: |
| |
| seth sp, #shigh(_stack) |
| add3 sp, sp, #low(_stack) |
| ldi fp, #0 |
| |
| # Clear the BSS. Do it in two parts for efficiency: longwords first |
| # for most of it, then the remaining 0 to 3 bytes. |
| |
| seth r2, #shigh(__bss_start) |
| add3 r2, r2, #low(__bss_start); R2 = start of BSS |
| seth r3, #shigh(_end) |
| add3 r3, r3, #low(_end) ; R3 = end of BSS + 1 |
| |
| sub r3, r2 ; R3 = BSS size in bytes |
| mv r4, r3 |
| srli r4, #2 ; R4 = BSS size in longwords (rounded down) |
| ldi r1, #0 ; clear R1 for longword store |
| addi r2, #-4 ; account for pre-inc store |
| beqz r4, .Lendloop1 ; any more to go? |
| .Lloop1: |
| st r1, @+r2 ; yep, zero out another longword |
| addi r4, #-1 ; decrement count |
| bnez r4, .Lloop1 ; go do some more |
| .Lendloop1: |
| and3 r4, r3, #3 ; get no. of remaining BSS bytes to clear |
| addi r2, #4 ; account for pre-inc store |
| beqz r4, .Lendloop2 ; any more to go? |
| .Lloop2: |
| stb r1, @r2 ; yep, zero out another byte |
| addi r2, #1 ; bump address |
| addi r4, #-1 ; decrement count |
| bnez r4, .Lloop2 ; go do some more |
| .Lendloop2: |
| |
| # Run code in the .init section. |
| # This will queue the .fini section to be run with atexit. |
| |
| bl __init |
| |
| # Call main, then exit. |
| |
| bl main |
| bl exit |
| |
| # If that fails just loop. |
| |
| .Lexit: |
| bra .Lexit |
