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authorKartik Agaram <vc@akkartik.com>2020-03-06 18:31:14 -0800
committerKartik Agaram <vc@akkartik.com>2020-03-06 18:34:27 -0800
commit8f256f1f2ee6a2a49816dd23d26cd120f526bf0b (patch)
tree314294998b527980cdf85ecb51386642bfbe3af4 /061read-byte.subx
parent4c19dd3968d2ce733073774867d97cc96b4277e6 (diff)
downloadmu-8f256f1f2ee6a2a49816dd23d26cd120f526bf0b.tar.gz
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.
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