Reorganize packages

src/examples/hello/hello.go

@@ -0,0 +1,41 @@
+
+package main
+
+const SIX = 6
+
+func main() {
+	println("Hello world from Go!")
+	println("The answer is:", calculateAnswer())
+	println("5 ** 2 =", square(5))
+	println("3 + 12 =", add(3, 12))
+	println("fib(11) =", fib(11))
+	println("sumrange(100) =", sumrange(100))
+}
+
+func calculateAnswer() int {
+	seven := 7
+	return SIX * seven
+}
+
+func square(n int) int {
+	return n * n
+}
+
+func add(a, b int) int {
+	return a + b
+}
+
+func fib(n int) int {
+	if n <= 2 {
+		return 1
+	}
+	return fib(n - 1) + fib(n - 2)
+}
+
+func sumrange(n int) int {
+	sum := 0
+	for i := 1; i <= n; i++ {
+		sum += i
+	}
+	return sum
+}

src/runtime/runtime.c

@@ -0,0 +1,49 @@
+
+#include <unistd.h>
+#include <string.h>
+#include <stdio.h>
+#include "runtime.h"
+
+#define print(buf, len) write(STDOUT_FILENO, buf, len)
+
+void __go_printstring(string_t str) {
+	write(STDOUT_FILENO, str.buf, str.len);
+}
+
+void __go_printint(intgo_t n) {
+	// Print integer in signed big-endian base-10 notation, for humans to
+	// read.
+	// TODO: don't recurse, but still be compact (and don't divide/mod
+	// more than necessary).
+	if (n < 0) {
+		print("-", 1);
+		n = -n;
+	}
+	intgo_t prevdigits = n / 10;
+	if (prevdigits != 0) {
+		__go_printint(prevdigits);
+	}
+	char buf[1] = {(n % 10) + '0'};
+	print(buf, 1);
+}
+
+void __go_printspace() {
+	print(" ", 1);
+}
+
+void __go_printnl() {
+	print("\n", 1);
+}
+
+void go_main() __asm__("main.main");
+
+void __go_runtime_main() {
+	go_main();
+}
+
+__attribute__((weak))
+int main() {
+	__go_runtime_main();
+
+	return 0;
+}

src/runtime/runtime.h

@@ -0,0 +1,11 @@
+
+#pragma once
+
+#include <stdint.h>
+
+typedef struct {
+	uint32_t len;  // TODO: size_t (or, let max string size depend on target/flag)
+	uint8_t  *buf; // points to string buffer itself
+} string_t;
+
+typedef int32_t intgo_t; // may be 64-bit