def register $reg1 group1 true
def register $reg2 group1 false
def register $reg3 group2 true
def bitfield $reg1.field1 0 2
def bitfield $reg1.field2 2 2
def mnemonic $reg1.field2 zero 0
def mnemonic $reg1.field2 one 1
def mnemonic $reg1.field2 two 2
def mnemonic $reg1.field2 three 3
push 1
pop $$reg1
push $$reg1
output
push 2
pop $$reg1.field1
push $$reg1.field1
output
push 4
pop $$reg1.field1
push $$reg1.field1
output
push 1
pop $$reg1.field2
push $$reg1
output
push zero 
pop $$reg1.field2
push $$reg1.field2
output
push $$reg1
output
push 2 
pop $$reg1.field2
push $$reg1.field2
output
push $$reg1
output
halt