Add check for causality

This commit is contained in:
Donald Sebastian Leung 2020-07-27 14:16:42 +08:00
parent 2421f1f6b6
commit 8cb5110199
1 changed files with 81 additions and 0 deletions

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from nmigen import *
from nmigen.hdl.ast import *
class rvfi_causal_check(Elaboratable):
def __init__(self, RISCV_FORMAL_ILEN=32, RISCV_FORMAL_XLEN=32):
self.RISCV_FORMAL_ILEN = RISCV_FORMAL_ILEN
self.RISCV_FORMAL_XLEN = RISCV_FORMAL_XLEN
self.reset = Signal(1)
self.check = Signal(1)
self.rvfi_valid = Signal(1)
self.rvfi_order = Signal(64)
self.rvfi_insn = Signal(self.RISCV_FORMAL_ILEN)
self.rvfi_trap = Signal(1)
self.rvfi_halt = Signal(1)
self.rvfi_intr = Signal(1)
self.rvfi_mode = Signal(2)
self.rvfi_ixl = Signal(2)
self.rvfi_rs1_addr = Signal(5)
self.rvfi_rs2_addr = Signal(5)
self.rvfi_rs1_rdata = Signal(self.RISCV_FORMAL_XLEN)
self.rvfi_rs2_rdata = Signal(self.RISCV_FORMAL_XLEN)
self.rvfi_rd_addr = Signal(5)
self.rvfi_rd_wdata = Signal(self.RISCV_FORMAL_XLEN)
self.rvfi_pc_rdata = Signal(self.RISCV_FORMAL_XLEN)
self.rvfi_pc_wdata = Signal(self.RISCV_FORMAL_XLEN)
self.rvfi_mem_addr = Signal(self.RISCV_FORMAL_XLEN)
self.rvfi_mem_rmask = Signal(int(self.RISCV_FORMAL_XLEN // 8))
self.rvfi_mem_wmask = Signal(int(self.RISCV_FORMAL_XLEN // 8))
self.rvfi_mem_rdata = Signal(self.RISCV_FORMAL_XLEN)
self.rvfi_mem_wdata = Signal(self.RISCV_FORMAL_XLEN)
def ports(self):
input_ports = [
self.reset,
self.check,
self.rvfi_valid,
self.rvfi_order,
self.rvfi_insn,
self.rvfi_trap,
self.rvfi_halt,
self.rvfi_intr,
self.rvfi_mode,
self.rvfi_ixl,
self.rvfi_rs1_addr,
self.rvfi_rs2_addr,
self.rvfi_rs1_rdata,
self.rvfi_rs2_rdata,
self.rvfi_rd_addr,
self.rvfi_rd_wdata,
self.rvfi_pc_rdata,
self.rvfi_pc_wdata,
self.rvfi_mem_addr,
self.rvfi_mem_rmask,
self.rvfi_mem_wmask,
self.rvfi_mem_rdata,
self.rvfi_mem_wdata
]
output_ports = []
return input_ports + output_ports
def elaborate(self, platform):
m = Module()
insn_order = AnyConst(64)
register_index = AnyConst(5)
found_non_causal = Signal(1, reset=0)
with m.If(self.reset):
m.d.sync += found_non_causal.eq(0)
with m.Else():
with m.If(self.check):
m.d.comb += Assume(register_index != 0)
m.d.comb += Assume(self.rvfi_valid)
m.d.comb += Assume(register_index == self.rvfi_rd_addr)
m.d.comb += Assume(insn_order == self.rvfi_order)
m.d.comb += Assert(~found_non_causal)
with m.Else():
with m.If(self.rvfi_valid & (self.rvfi_order > insn_order) & \
((register_index == self.rvfi_rs1_addr) | \
(register_index == self.rvfi_rs2_addr))):
m.d.sync += found_non_causal.eq(1)
return m