About MSP430FR5969, the number of times the instruction is executed

Hi,

This is a output test code below,PTXOUT output clock wave.It shall output the wave of the same  Duty cycle , But it is not .Please ,help me ,thanks.

R_prevState .set  R14

MOV #0xff , R_prevState
NOP

Normal_M_value_Low_8:
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[0]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]
MOV.B R_prevState, &PTXOUT ;[1]
INV R_prevState ;[1]

NOP
NOP
NOP