77 lines
1.5 KiB
ArmAsm
77 lines
1.5 KiB
ArmAsm
; FreeBSDで、死すコール番号を調べるには：/usr/include/sys/syscall.h
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; Linuxで、死すコール番号を調べるには：/usr/include/asm-generic/unistd.h
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; 下記のコードはFreeBSD向けの物です。
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bits 64
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default rel
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section .data
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hdr2 db "960 540", 10
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hdr3 db "255", 10
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section .rodata
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outfile db "output.ppm", 0
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hdr1 db "P6", 10
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err db "開くに失敗", 10
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errlen equ $-err
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w equ 960
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h equ 540
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section .text
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global _start
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_start:
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mov rax, 5 ; sys_openat
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lea rdi, [outfile]
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mov rsi, 0x100601 ; 0x100601 = 0001 0000 0000 0110 0000 0001 = 1048576 + 1024 + 512 + 1 = 1050113
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; O_WRONLY = 0x0001
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; O_CREAT = 0x0200
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; O_TRUNC = 0x0400
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; O_CLOEXEC = 0x010000
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; /usr/include/sys/fcntl.h
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mov rdx, 0o666 ; chmod 666
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syscall
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test rax, rax
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js error ; エラーがあれば
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mov rbx, rax ; ファイルディスクリプターをrbxに保存
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mov rax, 4 ; sys_write
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mov rdi, rbx ; fd
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lea rsi, [hdr1]
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mov rdx, 3
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syscall
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mov rax, 4
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mov rdi, rbx
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lea rsi, [hdr2]
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mov rdx, 8
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syscall
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mov rax, 4
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mov rdi, rbx
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lea rsi, [hdr3]
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mov rdx, 4
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syscall
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mov rax, 6 ; sys_close
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mov rdi, rbx
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syscall
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end:
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mov rax, 1 ; sys_exit
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xor rdi, rdi
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syscall
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error:
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mov rax, 4
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mov rdi, 2 ; stderr
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lea rsi, [err]
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mov rdx, errlen
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syscall
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mov rax, 1
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mov rdi, 1
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syscall
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