4 ms·
The same way AMD added 8 new GPRs, I imagine: by introducing a new instruction prefix.
by Joker_vD 9mo ago
The same way AMD added 8 new GPRs, I imagine: by introducing a new instruction prefix.
- bonzini 9mo agoYes, two in fact. One is the same prefix (with subtle differences of course, it's x86) that was introduced for AVX512's 32 registers. The other is new and it's a two byte extension (0xd6 0x??) of the REX prefix (0x40-0x4f). The longer prefix has extra functionality such as adding a third operand (i.e. add r8, r15, r16), blocking flags update, and accessing a few new instructions (push2, pop2, ccmp, ctest, cfcmov).