Attempting to decode: f3 48 a5 iclass REP_MOVSQ category STRINGOP ISA-extension LONGMODE ISA-set LONGMODE instruction-length 3 operand-width 64 effective-operand-width 64 effective-address-width 64 stack-address-width 64 iform-enum-name REP_MOVSQ iform-enum-name-dispatch (zero based) 0 iclass-max-iform-dispatch 1 Nominal opcode position 2 Nominal opcode 0xa5 Operands # TYPE DETAILS VIS RW OC2 BITS BYTES NELEM ELEMSZ ELEMTYPE REGCLASS # ==== ======= === == === ==== ===== ===== ====== ======== ======== 0 MEM0 (see below) SUPPRESSED CW Q 64 8 1 64 INT INVALID 1 BASE0 BASE0=RDI SUPPRESSED RCW ASZ 64 8 1 64 INT GPR 2 MEM1 (see below) SUPPRESSED CR Q 64 8 1 64 INT INVALID 3 BASE1 BASE1=RSI SUPPRESSED RCW ASZ 64 8 1 64 INT GPR 4 REG0 REG0=RCX SUPPRESSED RCW ASZ 64 8 1 64 INT GPR 5 REG1 REG1=RFLAGS SUPPRESSED R Y 64 8 1 64 INT FLAGS Memory Operands 0 written BASE= RDI/GPR ASZ0=64 1 read BASE= RSI/GPR ASZ1=64 MemopBytes = 8 FLAGS: reads-rflags df-tst read: df mask=0x400 written: mask=0x0 undefined: mask=0x0 ATTRIBUTES: FIXED_BASE0 FIXED_BASE1 REP REAL REP corresponding no-rep iclass: MOVSQ F3 PREFIX Number of legacy prefixes: 2 ISA SET: [LONGMODE] 0 CPUID GROUP NAME: [LONGMODE] 0 CPUID RECORD NAME: [INTEL64] {Leaf 0x80000001, subleaf 0x00000000, EDX[29:29]} = 1