Semantic bug in LZCNT

[basavesh]

LZCNT instruction computes wrong value as it doesn't take care of the size parameter.

For example: executing LZCNT_16 R10 R12 -> lzcntw %r12w, %r10w leads to different values in Jasmin and H/W asm.

Before execution:

R10: 11689315489894297136
R12: 6104740341430370735

After execution in Jasmin:

R10: 11689315489894236176
R12: 6104740341430370735

After execution in H/W asm:

R10: 11689315489894236161
R12: 6104740341430370735

More details below:

Jasmin single step:

Initial state:
ip: 0
RAX: 12779401926263320820
RCX: 11809738235967653070
RDX: 14235405625157437496
RBX: 8305324555075843050
RSP: 11998830535613101673
RBP: 10095525653015111164
RSI: 15237392406662427857
RDI: 5050672628792123946
R8: 3481965236275870841
R9: 14865427843756515456
R10: 11689315489894297136
R11: 7207364775942046353
R12: 6104740341430370735
R13: 7896153421605611015
R14: 784843899963345240
R15: 4150172742681634750

Running instruction:
        lzcntw  %r12w, %r10w
        
New state:
ip: 1
RAX: 12779401926263320820
RCX: 11809738235967653070
RDX: 14235405625157437496
RBX: 8305324555075843050
RSP: 11998830535613101673
RBP: 10095525653015111164
RSI: 15237392406662427857
RDI: 5050672628792123946
R8: 3481965236275870841
R9: 14865427843756515456
R10: 11689315489894236176
R11: 7207364775942046353
R12: 6104740341430370735
R13: 7896153421605611015
R14: 784843899963345240
R15: 4150172742681634750

H/W single step:
Before:

After: