Kartik Agaram 8f256f1f2e 6090 - new instruction: multiply by immediate ...

This is a 3-operand instruction:
  r32 = rm32 * imm32

It looks like https://c9x.me/x86/html/file_module_x86_id_138.html has a
bug, implying the same opcode supports a 2-operand version. I don't see
that in the Intel manual pdf, or at alternative sites like https://www.felixcloutier.com/x86/imul

Native runs seem to validate my understanding.

In the process I also fixed a bug in the existing multiply instruction
0f af: the only flags it sets are OF and CF. The other existing multiply
instruction f7 was doing things right.

2020-03-06 18:34:27 -08:00

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