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IMUL does not sign extend correctly #22

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YJDoc2 opened this issue Oct 4, 2023 · 0 comments · May be fixed by #24

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bug good first issue

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YJDoc2 commented Oct 4, 2023

As from a mail received :

start:
MOV AL, 0xF9 (-7)
MOV BL, 0x02 (2)
IMUL BL

It gives the result of 01F2. This answer is the result of unsigned number multiplication (MUL).
It is expected to give the answer of FFF2 (-14).

This is because of a bug in imul implementation which does the sign extension + expansion incorrectly.

YJDoc2 added bug good first issue labels

KiN4Tec linked a pull request

that will close this issue

Fix MUL/IMUL instructions #24

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