60 lines
1.5 KiB
Zig
60 lines
1.5 KiB
Zig
import "syscall.zig";
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// The compiler treats this file special by implicitly importing the function `main`
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// from the root source file as the symbol `zig_user_main`.
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const want_start_symbol = switch(@compile_var("os")) {
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linux => true,
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else => false,
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};
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const want_main_symbol = !want_start_symbol;
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var argc: isize = undefined;
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var argv: &&u8 = undefined;
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#attribute("naked")
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#condition(want_start_symbol)
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export fn _start() -> unreachable {
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switch (@compile_var("arch")) {
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x86_64 => {
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argc = asm("mov (%%rsp), %[argc]": [argc] "=r" (-> isize));
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argv = asm("lea 0x8(%%rsp), %[argv]": [argv] "=r" (-> &&u8));
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},
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i386 => {
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argc = asm("mov (%%esp), %[argc]": [argc] "=r" (-> isize));
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argv = asm("lea 0x4(%%esp), %[argv]": [argv] "=r" (-> &&u8));
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},
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else => unreachable{},
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}
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call_main()
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}
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fn strlen(ptr: &const u8) -> isize {
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var count: isize = 0;
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while (ptr[count] != 0) {
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count += 1;
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}
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return count;
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}
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fn call_main() -> unreachable {
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var args: [argc][]u8 = undefined;
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for (args) |arg, i| {
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const ptr = argv[i];
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args[i] = ptr[0...strlen(ptr)];
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}
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zig_user_main(args) %% exit(1);
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exit(0);
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}
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#condition(want_main_symbol)
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export fn main(argc: i32, argv: &&u8) -> i32 {
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var args: [argc][]u8 = undefined;
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for (args) |arg, i| {
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const ptr = argv[i];
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args[i] = ptr[0...strlen(ptr)];
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}
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zig_user_main(args) %% return 1;
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return 0;
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}
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