APPENDIX A. X86 APPENDIX A. X86
A.2.2 RBX/EBX/BX/BL
7th(byte number) 6th 5th 4th 3rd 2nd 1st 0th
RBXx64
EBX
BX
BH BLA.2.3 RCX/ECX/CX/CL.
7th(byte number) 6th 5th 4th 3rd 2nd 1st 0th
RCXx64
ECX
CX
CH CLAKAcounter: in this role it is used in REP prefixed instructions and also in shift instructions (SHL/SHR/RxL/RxR).
A.2.4 RDX/EDX/DX/DL
7th(byte number) 6th 5th 4th 3rd 2nd 1st 0th
RDXx64
EDX
DX
DH DLA.2.5 RSI/ESI/SI/SIL.
7th(byte number) 6th 5th 4th 3rd 2nd 1st 0th
RSIx64
ESI
SI
SILx64AKA“source index”. Used as source in the instructions REP MOVSx, REP CMPSx.
A.2.6 RDI/EDI/DI/DIL.
7th(byte number) 6th 5th 4th 3rd 2nd 1st 0th
RDIx64
EDI
DI
DILx64AKA“destination index”. Used as a pointer to the destination in the instructions REP MOVSx, REP STOSx.
A.2.7 R8/R8D/R8W/R8L
7th(byte number) 6th 5th 4th 3rd 2nd 1st 0th
R8
R8D
R8W
R8L