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75 lines
1.5 KiB
Markdown
75 lines
1.5 KiB
Markdown
# Python / Assembly Language
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It is possible to call your assembly language code from Python. In fact,
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it can be insanely easy. It can also be difficult. What differentiates
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the two are the arguments you need to pass.
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Python stores data very differently than C and therefore assembly
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language. All Python data types are objects, which for sets and dicts
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can make things difficult and outside the scope of this book.
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If you want to explore the subject deeply, we suggest
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[this link](https://realpython.com/python-bindings-overview)
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## Simple Example
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Take this trivial C function:
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```c
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int square(int x) {
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return x * x;
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}
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```
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It could be written in this way using our Apple / Linux convergence
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macros:
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```text
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#include "apple-linux-convergence.S"
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/*
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gcc -fPIC -shared -o my_square.so function.S
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*/
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.p2align 2
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.text
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GLABEL square
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#if defined(__APPLE__)
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_square:
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#else
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square:
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#endif
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mul x0, x0, x0
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ret
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.end
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```
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This function is a leaf and requires no interaction with the stack.
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Notice there is no `main()`.
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Using the following command line, turn your assembly language module
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into a "shared object" or .so file:
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```text
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gcc -fPIC -shared -o my_square.so function.S
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```
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`-fPIC` means generate position independent code. This allows the library
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to be relocated wherever the program loading the library wants it.
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Then, in Python:
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```python
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from ctypes import *
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so_file = "./my_square.so"
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my_funcs = CDLL(so_file)
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print(my_funcs.square(10))
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```
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It just works.
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## More to Come Here
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