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Write Hello World Using Only Raw syscall() Instructions

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Language

Compiler

2.0s Limit 256MB

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Implementation

Write Hello World program using only raw syscalls (no libc).

Requirements:

Use syscall() wrapper or inline assembly for syscalls
Implement SYS_write to print "Hello, World!"
Implement SYS_exit to exit cleanly
DO NOT use any libc functions (printf, puts, etc.)
Use correct register arguments for x86-64
Handle return values and errors
Print to stdout (file descriptor 1)
Calculate string length (without strlen)
Show syscall numbers and arguments
Demonstrate understanding of syscall mechanism
Explain each step in comments

Why This Matters

Bypassing libc to call `syscall()` directly is exactly how musl and Google's Fuchsia libc bootstrap their runtimes, and it's the same register convention (RAX for the number, RDI/RSI/RDX for arguments) that `strace` decodes and gdb inspects when debugging a crash. Static binaries built this way are also how minimal Docker base images and Go's early runtime avoided depending on a dynamically linked glibc entirely.

Hints

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Validation Suite

main.c

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