asm {
  _DIV_U64_BY_U64::
  PUSH  RBP
  MOV   RBP,RSP
  XOR   RDX,RDX
  MOV   RCX,64
  MOV   RAX,SF_ARG1[RBP]
  MOV   RBX,SF_ARG2[RBP]
@@1:    SHL1    RAX
  RCL1  RDX
  CMP   RBX,RDX
  JA    @@2
  INC   RAX
  SUB   RDX,RBX
@@2:    LOOP    @@1
  POP   RBP
  RET1  16
}

_extern _DIV_U64_BY_U64 I64 DivU64ByU64(I64 dividend,I64 divisor);

"123456/10=%d\n"
,DivU64ByU64(123456,10);