33 lines
959 B
Zig
33 lines
959 B
Zig
const SYS_write : isize = 1;
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const SYS_exit : isize = 60;
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const stdout_fileno : isize = 1;
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fn syscall1(number: isize, arg1: isize) -> isize {
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asm volatile ("syscall"
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: [ret] "={rax}" (-> isize)
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: [number] "{rax}" (number), [arg1] "{rdi}" (arg1)
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: "rcx", "r11")
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}
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fn syscall3(number: isize, arg1: isize, arg2: isize, arg3: isize) -> isize {
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asm volatile ("syscall"
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: [ret] "={rax}" (-> isize)
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: [number] "{rax}" (number), [arg1] "{rdi}" (arg1), [arg2] "{rsi}" (arg2), [arg3] "{rdx}" (arg3)
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: "rcx", "r11")
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}
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pub fn write(fd: isize, buf: &const u8, count: usize) -> isize {
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return syscall3(SYS_write, fd, buf as isize, count as isize);
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}
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pub fn exit(status: i32) -> unreachable {
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syscall1(SYS_exit, status as isize);
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unreachable;
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}
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// TODO error handling
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// TODO handle buffering and flushing
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pub fn print_str(str : string) -> isize {
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return write(stdout_fileno, str.ptr, str.len);
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}
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