Attempting to decode: f3 48 ab 
iclass REP_STOSQ	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_STOSQ
iform-enum-name-dispatch (zero based) 0
iclass-max-iform-dispatch 1
Nominal opcode position 2
Nominal opcode 0xab
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   REG0              REG0=RAX SUPPRESSED   R         Q   64     8     1     64        INT        GPR
3   REG1              REG1=RCX SUPPRESSED RCW       ASZ   64     8     1     64        INT        GPR
4   REG2           REG2=RFLAGS SUPPRESSED   R         Y   64     8     1     64        INT      FLAGS
Memory Operands
  0 written BASE= RDI/GPR  ASZ0=64
  MemopBytes = 8
FLAGS:
   reads-rflags df-tst 
       read:                            df  mask=0x400
    written:                                mask=0x0
  undefined:                                mask=0x0
ATTRIBUTES: FIXED_BASE0 REP 
REAL REP 	corresponding no-rep iclass: STOSQ
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