39 lines
752 B
NASM
39 lines
752 B
NASM
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bits 64
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SECTION .data
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; empty
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echobuf db 1024
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SECTION .text
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global _start
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_start:
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;int3
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read:
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; sys_read(stdin, buf, buflen)
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mov rax,0
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mov rdi,0 ; arg1: fd (0 = stdin)
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lea rsi,[echobuf] ; arg2: buffer
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mov rdx,1024 ; arg3: buflen
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syscall
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test rax, rax
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jz exit
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; sys_write(stdout, buf, buflen)
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mov rdx,rax ; arg3: buflen
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mov rax,1 ; system call number (1 = sys_write)
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mov rdi,1 ; arg1: fd (1 = stdout)
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lea rsi,[echobuf] ; arg2: buffer
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syscall
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jmp read
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exit:
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; sys_exit(42)
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mov rax,60 ; system call number (sys_exit)
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mov rdi,0 ; system call return value
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syscall
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times 64 nop
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