...

line=[sub	rsi, 1]
rcx=arg4
rsi=(arg2 - 1)
rbx=initial_RBX
rdx=arg3
rdi=arg1
rax=initial_RAX

line=[add	rdi, rsi]
rcx=arg4
rsi=(arg2 - 1)
rbx=initial_RBX
rdx=arg3
rdi=(arg1 + (arg2 - 1))
rax=initial_RAX

line=[not	rsi]
rcx=arg4
rsi=(~(arg2 - 1))
rbx=initial_RBX
rdx=arg3
rdi=(arg1 + (arg2 - 1))
rax=initial_RAX

line=[and	rdi, rsi]
rcx=arg4
rsi=(~(arg2 - 1))
rbx=initial_RBX
rdx=arg3
rdi=((arg1 + (arg2 - 1)) & (~(arg2 - 1)))
rax=initial_RAX

line=[mov	rax, rdi]
rcx=arg4
rsi=(~(arg2 - 1))
rbx=initial_RBX
rdx=arg3
rdi=((arg1 + (arg2 - 1)) & (~(arg2 - 1)))
rax=((arg1 + (arg2 - 1)) & (~(arg2 - 1)))

...

result=((arg1 + (arg2 - 1)) & (~(arg2 - 1)))