class MIP:
- def __init__(self, comb, sync):
- self.comb = comb
- self.sync = sync
- self.meip = Signal(name="mip_meip") # TODO: implement ext interrupts
- self.seip = Signal(name="mip_seip")
- self.ueip = Signal(name="mip_uiep")
- self.mtip = Signal(name="mip_mtip") # TODO: implement timer interrupts
- self.stip = Signal(name="mip_stip")
- self.msip = Signal(name="mip_stip")
- self.utip = Signal(name="mip_utip")
- self.ssip = Signal(name="mip_ssip")
- self.usip = Signal(name="mip_usip")
-
- for n in dir(self):
- if n in ['make', 'comb', 'sync'] or n.startswith("_"):
- continue
- self.comb += getattr(self, n).eq(0x0)
-
- def make(self):
- return Cat( self.usip, self.ssip, 0, self.msip,
- self.utip, self.stip, 0, self.mtip,
- self.ueip, self.seip, 0, self.meip, )
+ def __init__(self):
+ self.mip = Signal(32)
class M:
# return [m.mcause.eq(0),
# ]
- def handle_trap(self, m, ms, ft, dc, load_store_misaligned):
- s = [ms.mpie.eq(ms.mie),
- ms.mie.eq(0),
- m.mepc.eq(Mux(ft.action == FA.noerror_trap,
- ft.output_pc + 4,
- ft.output_pc))]
-
- # fetch action ack trap
- i = If(ft.action == FA.ack_trap,
- m.mcause.eq(cause_instruction_access_fault)
- )
-
- # ecall/ebreak
- i = i.Elif((dc.act & DA.trap_ecall_ebreak) != 0,
- m.mcause.eq(Mux(dc.immediate[0],
- cause_machine_environment_call,
- cause_breakpoint))
- )
-
- # load
- i = i.Elif((dc.act & DA.load) != 0,
- If(load_store_misaligned,
- m.mcause.eq(cause_load_address_misaligned)
- ).Else(
- m.mcause.eq(cause_load_access_fault)
- )
- )
-
- # store
- i = i.Elif((dc.act & DA.store) != 0,
- If(load_store_misaligned,
- m.mcause.eq(cause_store_amo_address_misaligned)
- ).Else(
- m.mcause.eq(cause_store_amo_access_fault)
- )
- )
-
- # jal/jalr -> misaligned=error, otherwise jump
- i = i.Elif((dc.act & (DA.jal | DA.jalr | DA.branch)) != 0,
- m.mcause.eq(cause_instruction_address_misaligned)
- )
-
- # defaults to illegal instruction
- i = i.Else(m.mcause.eq(cause_illegal_instruction))
-
- s.append(i)
+ def handle_trap(self, mcause, mepc, mie, mpie):
+ s = [mcause.eq(self.new_mcause),
+ mepc.eq(self.new_mepc),
+ mpie.eq(self.new_mpie),
+ mie.eq(self.new_mie)]
return s
def main_block(self, mtvec, mip, minfo, misa, csr, mi, m, mstatus, mie,
lui_auipc_result):
c = {}
c[FOS.empty] = []
- c[FOS.trap] = self.handle_trap(m, mstatus, ft, dc,
- load_store_misaligned)
+ c[FOS.trap] = self.handle_trap(m.mcause, m.mepc,
+ mstatus.mie, mstatus.mpie)
c[FOS.valid] = self.handle_valid(mtvec, mip, minfo, misa, csr, mi, m,
mstatus, mie, ft, dc,
load_store_misaligned,
loaded_value,
alu_result,
lui_auipc_result)
- return Case(ft.output_state, c)
+ return [self.regs.w_en.eq(0),
+ Case(ft.output_state, c),
+ self.regs.w_en.eq(0)]
def write_register(self, rd, val):
return [self.regs.rd.eq(rd),
lui_auipc_result):
# fetch action ack trap
i = If((ft.action == FA.ack_trap) | (ft.action == FA.noerror_trap),
- [self.handle_trap(m, mstatus, ft, dc,
- load_store_misaligned),
- self.regs.w_en.eq(0) # no writing to registers
- ]
+ self.handle_trap(m.mcause, m.mepc, mstatus.mie, mstatus.mpie)
)
# load
i = i.Elif((dc.act & (DA.fence | DA.fence_i |
DA.store | DA.branch)) != 0,
# do nothing
- self.regs.w_en.eq(0) # no writing to registers
)
return i
# mip
c[csr_mip ] = [
- csr_output_value.eq(mip.make()),
+ csr_output_value.eq(mip.mip),
csr.evaluate_csr_funct3_op(dc.funct3, csr_output_value,
csr_written_value),
]
mstatus = MStatus(self.comb, self.sync)
mie = MIE(self.comb, self.sync)
misa = Misa(self.comb, self.sync)
- mip = MIP(self.comb, self.sync)
+ mip = MIP()
+
+ mp = Instance("CPUMIP", name="cpu_mip",
+ o_mip = mip.mip)
+
+ self.specials += mp
mii = Instance("CPUMIE", name="cpu_mie",
o_mie = mie.mie,
minfo = MInfo(self.comb)
+ self.new_mcause = Signal(32)
+ self.new_mepc = Signal(32)
+ self.new_mpie = Signal()
+ self.new_mie = Signal()
+
+ ht = Instance("CPUHandleTrap", "cpu_handle_trap",
+ i_ft_action = ft.action,
+ i_ft_output_pc = ft.output_pc,
+ i_dc_action = dc.act,
+ i_dc_immediate = dc.immediate,
+ i_load_store_misaligned = load_store_misaligned,
+ i_mie = mstatus.mie,
+ o_mcause = self.new_mcause,
+ o_mepc = self.new_mepc,
+ o_mpie = self.new_mpie,
+ o_mie = self.new_mie)
+
+ self.specials += ht
+
self.sync += If(~self.reset,
self.main_block(mtvec, mip, minfo, misa, csr, mi, m,
mstatus, mie, ft, dc,