x86: Carry flag calculated incorrectly for LZCNT if source=dest

[Sleigh-InSPECtor]

The carry flag for the LZCNT instruction should be calculated based on the input value of the source operand. However, if the destination operand is the same as the source operand (e.g., LZCNT EAX,EAX) then the carry flag is computed based the result of the LZCNT operation instead of the input value.

This PR fixes this by storing the input value into a temporary which is later used for computing the carry flag.

e.g.,

• 66f30fbdc0 "LZCNT AX,AX" wwith AX=ffff

  • Hardware Reference (AMD CPU & Intel CPU): { AX=0x0, ZF=1, CF=0 }
  • x86:LE:64:default (Existing): { AX=0x0, ZF=1, CF=1 }
  • x86:LE:64:default (This patch): { AX=0x0, ZF=1, CF=0 }

• f30fbdc0 "LZCNT EAX,EAX" with EAX=0xffff_ffff

  • Hardware Reference (AMD CPU & Intel CPU): { EAX=0x0, ZF=1, CF=0 }
  • x86:LE:64:default (Existing): { EAX=0x0, ZF=1, CF=1 }
  • x86:LE:64:default (This patch): { EAX=0x0, ZF=1, CF=0 }

• f3480fbdc0 "LZCNT RAX,RAX" with RAX=0xffff_ffff_ffff_ffff

  • Hardware Reference (AMD CPU & Intel CPU): { RAX=0x0, ZF=1, CF=0 }
  • x86:LE:64:default (Existing): { RAX=0x0, ZF=1, CF=1 }
  • x86:LE:64:default (This patch): { RAX=0x0, ZF=1, CF=0 }