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crosscompiler:hardware [2016/02/25 13:33] – external edit 127.0.0.1 | crosscompiler:hardware [2020/12/10 15:29] (current) – ursgraf | ||
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====== Accessing the Hardware ====== | ====== Accessing the Hardware ====== | ||
- | Java was developed as a save 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 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 |
By using '' | By using '' | ||
* read from absolute memory locations (1, 2, 4, 8 bytes) | * read from absolute memory locations (1, 2, 4, 8 bytes) | ||
* write to 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 | * 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 static method at compile time | ||
+ | * get the address of a object | ||
+ | |||
+ | Depending on the processor architecture there are some more unsafe capabilities. | ||
+ | ==== On the PowerPC platform ==== | ||
+ | '' | ||
+ | * read and write directly to machine registers (GPRs, FPRs, SPRs) | ||
+ | * enable the use of floats for exception routines | ||
+ | |||
+ | ==== On the ARM platform ==== | ||
+ | '' | ||
+ | * read and write directly to machine registers (GPRs, EXTRs, CPRs) | ||
* enable the use of floats for exception routines | * enable the use of floats for exception routines | ||
- | The API of US.java can be found under: | + | The API of US can be found under: |