LA 1.1.1 - select_from_table.c

unsigned __int8 __fastcall select_from_table(__int64 a1, unsigned int total_entries)
{
  __int64 v2; // x8
  __int64 v3; // x9
  unsigned __int64 v4; // x8
  unsigned __int64 v5; // x9
  unsigned __int64 v6; // x9
  __int64 s0; // x10
  __int64 s1; // x11
  __int64 v9; // x12
  int v10; // w8
  __int64 v11; // x10
  unsigned int rand; // w8

  if ( total_entries < 2 )
    return 0;
  v2 = __clz(total_entries);
  v3 = 31LL;
  if ( ((0x7FFFFFFFu >> v2) & total_entries) != 0 )
    v3 = 32LL;
  v4 = v3 - v2;
  v5 = v4 >> 6;
  if ( (v4 & 0x3F) != 0 )
    ++v5;
  if ( v5 > v4 )
    LODWORD(v6) = 0;
  else
    v6 = 0xFFFFFFFFFFFFFFFFLL >> -(v4 / v5);
  s0 = *(a1 + 112);
  s1 = *(a1 + 120);
  do
  {
    v9 = s0 ^ s1;
    v10 = s0 + s1;
    v11 = s0 ^ s1 ^ __ROR8__(s0, 40);
    s1 = __ROR8__(v9, 27);
    rand = v10 & v6;
    s0 = v11 ^ (v9 << 16);
  }
  while ( rand >= total_entries );
  *(a1 + 112) = s0;
  *(a1 + 120) = s1;
  return rand;
}


------

.text:00000071008273D4 ; unsigned __int8 __fastcall select_from_table(__int64 a1, unsigned int total_entries)
.text:00000071008273D4 select_from_table                       ; CODE XREF: sub_710078103C+88↑p
.text:00000071008273D4                                         ; sub_71007C9178+124↑p ...
.text:00000071008273D4                 CMP             W1, #2
.text:00000071008273D8                 B.CC            loc_710082744C
.text:00000071008273DC                 CLZ             W8, W1
.text:00000071008273E0                 MOV             W9, #0x7FFFFFFF
.text:00000071008273E4                 LSR             W9, W9, W8
.text:00000071008273E8                 TST             W9, W1
.text:00000071008273EC                 MOV             W9, #0x1F
.text:00000071008273F0                 CINC            X9, X9, NE
.text:00000071008273F4                 SUB             X8, X9, X8
.text:00000071008273F8                 LSR             X9, X8, #6
.text:00000071008273FC                 TST             X8, #0x3F
.text:0000007100827400                 CINC            X9, X9, NE
.text:0000007100827404                 CMP             X9, X8
.text:0000007100827408                 B.HI            loc_7100827458
.text:000000710082740C                 UDIV            X8, X8, X9
.text:0000007100827410                 MOV             X9, #0xFFFFFFFFFFFFFFFF
.text:0000007100827414                 NEG             X8, X8
.text:0000007100827418                 LSR             X9, X9, X8
.text:000000710082741C
.text:000000710082741C loc_710082741C                          ; CODE XREF: select_from_table+88↓j
.text:000000710082741C                 LDP             X10, X11, [X0,#0x70]
.text:0000007100827420
.text:0000007100827420 loc_7100827420                          ; CODE XREF: select_from_table+68↓j
.text:0000007100827420                 EOR             X12, X10, X11
.text:0000007100827424                 ADD             X8, X10, X11
.text:0000007100827428                 EOR             X10, X12, X10,ROR#40
.text:000000710082742C                 EXTR            X11, X12, X12, #0x1B
.text:0000007100827430                 AND             X8, X8, X9
.text:0000007100827434                 CMP             W8, W1
.text:0000007100827438                 EOR             X10, X10, X12,LSL#16
.text:000000710082743C                 B.CS            loc_7100827420
.text:0000007100827440                 STP             X10, X11, [X0,#0x70]
.text:0000007100827444                 MOV             W0, W8
.text:0000007100827448                 RET
.text:000000710082744C ; ---------------------------------------------------------------------------
.text:000000710082744C
.text:000000710082744C loc_710082744C                          ; CODE XREF: select_from_table+4↑j
.text:000000710082744C                 MOV             W8, WZR
.text:0000007100827450                 MOV             W0, W8
.text:0000007100827454                 RET
.text:0000007100827458 ; ---------------------------------------------------------------------------
.text:0000007100827458
.text:0000007100827458 loc_7100827458                          ; CODE XREF: select_from_table+34↑j
.text:0000007100827458                 MOV             X9, XZR
.text:000000710082745C                 B               loc_710082741C
.text:000000710082745C ; End of function select_from_table