def genVar(x):
# assuming x is ST.Var, ST.Ref, ST.Const
# for ST.Const: no code, x.val is constant
# for ST.Var: x.reg is FP for local, 0 for global vars,
# x.adr is relative or absolute address
# for ST.Ref: address is loaded into register
# returns ST.Var, ST.Const
if type(x) == Const:
y = x
else:
if x.lev == 0:
s = R0
elif x.lev == curlev:
s = FP
else:
mark("level!")
s = R0
y = Var(x.tp)
y.lev = x.lev
if type(x) == Ref: # reference is loaded into register
r = obtainReg()
putM("lw", r, s, x.adr)
y.reg, y.adr = r, 0
elif type(x) == Var:
y.reg, y.adr = s, x.adr
else:
y = x # error, pass dummy item
return y
def genVar(x):
# assuming x is ST.Var, ST.Ref, ST.Const
# for ST.Const: no code, x.val is constant
# for ST.Var: x.reg is FP for local, 0 for global vars,
# x.adr is relative or absolute address
# for ST.Ref: address is loaded into register
# returns ST.Var, ST.Const
if type(x) == Const: y = x
else:
if x.lev == 0: s = R0
elif x.lev == curlev: s = FP
else:
mark('level!')
s = R0
y = Var(x.tp)
y.lev = x.lev
if type(x) == Ref: # reference is loaded into register
r = obtainReg()
putM('lw', r, s, x.adr)
y.reg, y.adr = r, 0
elif type(x) == Var:
y.reg, y.adr = s, x.adr
else:
y = x # error, pass dummy item
return y
def genVar(x): # version supporting parameters in registers
if 0 < x.lev < curlev: mark('level!')
if type(x) == Ref:
y = Var(x.tp); y.lev = x.lev
if x.reg in ('$a0', '$a1', '$a2', '$a3'): # reference already in register, use it
y.reg, y.adr = x.reg, 0 # variable at M[y.reg]
else: # reference is loaded into register
y.reg, y.adr = obtainReg(), 0 # variable at M[y.reg]
putMemOp('lw', y.reg, x.reg, x.adr)
elif type(x) == Var:
if x.reg in ('$a0', '$a1', '$a2', '$a3'): # value already in register, use it
y = Reg(x.tp, x.reg) #; y.lev, x.adr = x.lev, x.adr
else:
y = Var(x.tp); y.lev, y.reg, y.adr = x.lev, x.reg, x.adr
else: assert False
return y
def genVar(x):
if x.lev == 0: s = R0 # global variable at x.adr
elif x.lev == curlev: s = FP # local variable, FP relative
else:
mark('level!')
s = R0
y = Var(x.tp)
y.lev = x.lev
if type(x) == Ref: # reference is loaded into register
r = obtainReg()
putMemOp('lw', r, s, x.adr)
y.reg, y.adr = r, 0 # variable at (y.reg)
elif type(x) == Var:
y.reg, y.adr = s, x.adr
else:
assert False
return y