Add README

README.markdown

@@ -0,0 +1,65 @@
+# TinyGo - Go compiler for microcontrollers
+
+> We never expected Go to be an embedded language and so it's got serious
+> problems [...].
+
+-- Rob Pike, [GopherCon 2014 Opening Keynote](https://www.youtube.com/watch?v=VoS7DsT1rdM&feature=youtu.be&t=2799)
+
+TinyGo is a project to bring Go to microcontrollers and small systems with a
+single processor core. It is similar to [emgo](https://github.com/ziutek/emgo)
+but a major difference is that I want to keep the Go memory model (which implies
+garbage collection of some sort). Another difference is that TinyGo uses LLVM
+internally instead of emitting C, which hopefully leads to smaller and more
+efficient code and certainly leads to more flexibility.
+
+My original reasoning was: if [Python](https://micropython.org/) can run on
+microcontrollers, then certainly [Go](https://golang.org/) should be able to and
+run on even lower level micros.
+
+Example program (blinky):
+
+```go
+import "machine"
+
+func main() {
+	led := machine.GPIO{machine.LED}
+	led.Configure(machine.GPIOConfig{Mode: machine.GPIO_OUTPUT})
+	for {
+		led.Low()
+		runtime.Sleep(runtime.Millisecond * 1000)
+
+		led.High()
+		runtime.Sleep(runtime.Millisecond * 1000)
+	}
+}
+```
+
+Currently supported features:
+
+  * control flow
+  * many (but not all) basic types: most ints, strings, structs
+  * function calling
+  * interfaces for basic types (with type switches and asserts)
+  * goroutines (very initial support)
+  * function pointers (non-blocking)
+
+Not yet supported:
+
+  * float, complex, etc.
+  * garbage collection
+  * interface methods
+  * channels
+  * introspection (if it ever gets implemented)
+  * standard library (needs more language support)
+  * `defer`
+  * closures
+  * ...
+
+## Analysis
+
+The goal is to reduce code size (and increase performance) by performing all
+kinds of whole-program analysis passes. The official Go compiler doesn't do a
+whole lot of analysis (except for escape analysis) becauses it needs to be fast,
+but embedded programs are necessarily smaller so it becomes practical. And I
+think especially program size can be reduced by a large margin when actually
+trying to optimize for it.