move get_fetch_action to separate verilog file

[rv32.git] / cpu.py

diff --git a/cpu.py b/cpu.py
index ff464520b56b73f61460cabf245fe9d76a31b250..bdf234d742d833038a1cca4b209f71b5aa5093b3 100644 (file)
--- a/cpu.py
+++ b/cpu.py
@@ -190,74 +190,6 @@ class Fetch:
         self.output_instruction = Signal(32, name="fetch_ouutput_instruction")
         self.output_state = Signal(fetch_output_state,name="fetch_output_state")
 
-    def get_fetch_action(self, dc_act, load_store_misaligned, mi_rw_wait,
-                         mi_rw_address_valid,
-                         branch_taken, misaligned_jump_target,
-                         csr_op_is_valid):
-        c = {}
-        c["default"] = self.action.eq(FA.default) # XXX should be 32'XXXXXXXX?
-        c[FOS.empty] = self.action.eq(FA.default)
-        c[FOS.trap] = self.action.eq(FA.ack_trap)
-
-        # illegal instruction -> error trap
-        i= If((dc_act & DA.trap_illegal_instruction) != 0,
-                 self.action.eq(FA.error_trap)
-              )
-
-        # ecall / ebreak -> noerror trap
-        i = i.Elif((dc_act & DA.trap_ecall_ebreak) != 0,
-                 self.action.eq(FA.noerror_trap))
-
-        # load/store: check alignment, check wait
-        i = i.Elif((dc_act & (DA.load | DA.store)) != 0,
-                If((load_store_misaligned | ~mi_rw_address_valid),
-                    self.action.eq(FA.error_trap) # misaligned or invalid addr
-                ).Elif(mi_rw_wait,
-                    self.action.eq(FA.wait) # wait
-                ).Else(
-                    self.action.eq(FA.default) # ok
-                )
-              )
-
-        # fence
-        i = i.Elif((dc_act & DA.fence) != 0,
-                 self.action.eq(FA.fence))
-
-        # branch -> misaligned=error, otherwise jump
-        i = i.Elif((dc_act & DA.branch) != 0,
-                If(branch_taken,
-                    If(misaligned_jump_target,
-                        self.action.eq(FA.error_trap)
-                    ).Else(
-                        self.action.eq(FA.jump)
-                    )
-                 ).Else(
-                        self.action.eq(FA.default)
-                 )
-              )
-
-        # jal/jalr -> misaligned=error, otherwise jump
-        i = i.Elif((dc_act & (DA.jal | DA.jalr)) != 0,
-                If(misaligned_jump_target,
-                    self.action.eq(FA.error_trap)
-                ).Else(
-                    self.action.eq(FA.jump)
-                )
-              )
-
-        # csr -> opvalid=ok, else error trap
-        i = i.Elif((dc_act & DA.csr) != 0,
-                If(csr_op_is_valid,
-                    self.action.eq(FA.default)
-                ).Else(
-                    self.action.eq(FA.error_trap)
-                )
-              )
-
-        c[FOS.valid] = i
-
-        return Case(self.output_state, c)
-
 class CSR:
     def __init__(self, comb, sync, dc, register_rs1):
         self.comb = comb
@@ -830,10 +762,18 @@ class CPU(Module):
         # CSR decoding
         csr = CSR(self.comb, self.sync, dc, self.regs.rs1)
 
-        self.comb += ft.get_fetch_action(dc.act, load_store_misaligned,
-                                 mi.rw_wait, mi.rw_address_valid,
-                                 branch_taken, misaligned_jump_target,
-                                 csr.op_is_valid)
+        fi = Instance("CPUFetchAction", name="cpu_fetch_action",
+            o_fetch_action = ft.action,
+            i_output_state = ft.output_state,
+            i_dc_act = dc.act,
+            i_load_store_misaligned = load_store_misaligned,
+            i_mi_rw_wait = mi.rw_wait,
+            i_mi_rw_address_valid = mi.rw_address_valid,
+            i_branch_taken = branch_taken,
+            i_misaligned_jump_target = misaligned_jump_target,
+            i_csr_op_is_valid = csr.op_is_valid)
+
+        self.specials += fi
 
         minfo = MInfo(self.comb)