Intel® ISA Extensions
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EVEX & VEX : operands encoding



I have a question about EVEX encoding and more precisely, about operands encoding with EVEX present (SIB, VSIB, EVEX.vvvv, ModR/M). According to,

Four bits R, X, B, and W from the REX prefix. W expands the operand size to 64 bits or serves as an additional opcode, R expands reg, B expands r/m or reg, and X and B expand index and base in the SIB byte. Comparing to the VEX prefix, RXB are provided in non-inversed forms, just like in the REX prefix.

1. Does it mean EVEX.R, EVEX.B, EVEX.X must be used without any 1's complement (while 1's complement is applyed on VEX.RBX) ?

2. Is there any "official" documentation about this ?

3. What about EVEX.V' ? Must we apply a 1's complement ?


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