37 lines
1.1 KiB
Python
37 lines
1.1 KiB
Python
|
from nmigen import *
|
||
|
|
|
||
|
|
from ..isa import Funct3
|
||
|
|
|
||
|
|
|
||
|
|
__all__ = ["CompareUnit"]
|
||
|
|
|
||
|
|
|
||
|
|
class CompareUnit(Elaboratable):
|
||
|
|
def __init__(self):
|
||
|
|
self.op = Signal(3)
|
||
|
|
self.zero = Signal()
|
||
|
|
self.negative = Signal()
|
||
|
|
self.overflow = Signal()
|
||
|
|
self.carry = Signal()
|
||
|
|
|
||
|
|
self.condition_met = Signal()
|
||
|
|
|
||
|
|
def elaborate(self, platform):
|
||
|
|
m = Module()
|
||
|
|
|
||
|
|
with m.Switch(self.op):
|
||
|
|
with m.Case(Funct3.BEQ):
|
||
|
|
m.d.comb += self.condition_met.eq(self.zero)
|
||
|
|
with m.Case(Funct3.BNE):
|
||
|
|
m.d.comb += self.condition_met.eq(~self.zero)
|
||
|
|
with m.Case(Funct3.BLT):
|
||
|
|
m.d.comb += self.condition_met.eq(~self.zero & (self.negative != self.overflow))
|
||
|
|
with m.Case(Funct3.BGE):
|
||
|
|
m.d.comb += self.condition_met.eq(self.negative == self.overflow)
|
||
|
|
with m.Case(Funct3.BLTU):
|
||
|
|
m.d.comb += self.condition_met.eq(~self.zero & self.carry)
|
||
|
|
with m.Case(Funct3.BGEU):
|
||
|
|
m.d.comb += self.condition_met.eq(~self.carry)
|
||
|
|
|
||
|
|
return m
|