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Fix undefined behavior #367

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pitust wants to merge 1 commit into bellard:master from pitust:master

pitust commented Nov 16, 2024 •

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The current implementation of the M4 macro leads to a signed integer overflow error, which is undefined behavior:

The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated bits are filled with zeros. If E1 has
an unsigned type, the value of the result is E1 × 2E2, wrapped around. If E1 has a signed type and
nonnegative value, and E1 × 2^E2 is representable in the result type, then that is the resulting value;
otherwise, the behavior is undefined

(emphasis added, N3219 6.5.8.5)


          Fix undefined behavior

1df5cbe

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