zig/std/bootstrap.zig
2016-03-01 14:11:38 -07:00

61 lines
1.4 KiB
Zig

// This file is in a package which has the root source file exposed as "@root".
const root = @import("@root");
const linux = @import("linux.zig");
const want_start_symbol = switch(@compile_var("os")) {
linux => true,
else => false,
};
const want_main_symbol = !want_start_symbol;
var argc: isize = undefined;
var argv: &&u8 = undefined;
#attribute("naked")
#condition(want_start_symbol)
export fn _start() -> unreachable {
switch (@compile_var("arch")) {
x86_64 => {
argc = asm("mov (%%rsp), %[argc]": [argc] "=r" (-> isize));
argv = asm("lea 0x8(%%rsp), %[argv]": [argv] "=r" (-> &&u8));
},
i386 => {
argc = asm("mov (%%esp), %[argc]": [argc] "=r" (-> isize));
argv = asm("lea 0x4(%%esp), %[argv]": [argv] "=r" (-> &&u8));
},
else => unreachable{},
}
call_main_and_exit()
}
fn strlen(ptr: &const u8) -> isize {
var count: isize = 0;
while (ptr[count] != 0) {
count += 1;
}
return count;
}
fn call_main() -> %void {
var args: [argc][]u8 = undefined;
for (args) |arg, i| {
const ptr = argv[i];
args[i] = ptr[0...strlen(ptr)];
}
return root.main(args);
}
fn call_main_and_exit() -> unreachable {
call_main() %% linux.exit(1);
linux.exit(0);
}
#condition(want_main_symbol)
export fn main(c_argc: i32, c_argv: &&u8) -> i32 {
argc = c_argc;
argv = c_argv;
call_main() %% return 1;
return 0;
}