Accessing the Hardware

Java was developed as a safe language. It does not allow direct access and manipulation of absolute memory locations. Nevertheless this is essential for embedded programming. We therefore include this possibility by the use a special java class org.deepjava.unsafe.US (US stand for unsafe). Wenn methods of this class are used the code generator inserts machine code accordingly.
By using US.java you can

• read from absolute memory locations (1, 2, 4, 8 bytes)
• write to absolute memory locations (1, 2, 4, 8 bytes)
• test a bit at an absolute memory location
• directly insert machine code
• get the address of a static method at compile time
• get the address of a object

Depending on the processor architecture there are some more unsafe capabilities.

org.deepjava.unsafe.ppc.US implements

• read and write directly to machine registers (GPRs, FPRs, SPRs)
• enable the use of floats for exception routines

org.deepjava.unsafe.arm.US implements

• read and write directly to machine registers (GPRs, EXTRs, CPRs)
• enable the use of floats for exception routines

The API of US can be found under: API US, API US PPC, API US ARM