Minimal semihosted ARM Cortex-M "Hello World"

The following is an extremely minimal, semihosted "Hello World" D program for ARM Cortex-M processors.

Goals

• Verify ARM Cortex-M toolchain (compiler-->linker-->debugger)
• Demonstrate how much of the D runtime and D standard library are required to begin programming for the ARM Cortex-M (essentially none)
• Demonstrate that linking to C code is not necessary
• Demonstrate that all required assembly code can be done within D

Tools

• (compiler) LDC with ARM backend
• (linker & debugger) GNU Tools for ARM Embedded Processors 4.7-2013-q3
• (GDB server) OpenOCD 0.7.0
• (JTAG emulator) JTAG-lock-pick Tiny 2