extern printf extern exit global main section .data ; Data section, initialized variables msg: db "Hello world", 0 ; C string needs 0 fmt: db "%s", 10, 0 ; The printf format, "\n",'0' section .text: main: ; Microsoft X86_64 Calling convention: ; - The first four integer or pointer parameters are passed in the rcx, rdx, r8, and r9 registers. ; - The first four floating-point parameters are passed in the first four SSE registers, xmm0-xmm3. ; - The caller reserves space on the stack for arguments passed in registers. The called function can use this space to spill the contents of registers to the stack. ; - Any additional arguments are passed on the stack. ; - An integer or pointer return value is returned in the rax register, while a floating-point return value is returned in xmm0. ; see https://learn.microsoft.com/en-us/windows-hardware/drivers/debugger/x64-architecture sub rsp, 32 ; reserve stack space for call lea rcx, [rel fmt] ; first parameter lea rdx, [rel msg] ; secodng parameter call printf add rsp,32 ; restore stack mov eax,0 ; exit code ret