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cleanup, use sync instead of comb where appropriate
[rv32.git]
/
cpu_fetch_stage.py
diff --git
a/cpu_fetch_stage.py
b/cpu_fetch_stage.py
index f35e68c447c491032cc05b2ae0804450c0d4322a..3d25d3507cdf8362b5467bbca2cf51240559affe 100644
(file)
--- a/
cpu_fetch_stage.py
+++ b/
cpu_fetch_stage.py
@@
-41,11
+41,12
@@
class CPUFetchStage(Module):
#input [31:0] memory_interface_fetch_data,
self.memory_interface_fetch_data = Signal(32)
self.memory_interface_fetch_valid = Signal()
#input [31:0] memory_interface_fetch_data,
self.memory_interface_fetch_data = Signal(32)
self.memory_interface_fetch_valid = Signal()
- input `fetch_action fetch_action,
- input [31:0] target_pc,
+ self.fetch_action = Signal(fetch_action)
+ self.target_pc = Signal(32)
self.output_pc = Signal(32, reset=reset_vector)
self.output_instruction = Signal(32)
self.output_pc = Signal(32, reset=reset_vector)
self.output_instruction = Signal(32)
- output reg `fetch_output_state output_state
+ self.output_state = Signal(fetch_output_state,
+ reset=fetch_output_state_empty)
self.comb += [
self.cd_sys.clk.eq(self.clk),
self.comb += [
self.cd_sys.clk.eq(self.clk),
@@
-54,7
+55,11
@@
class CPUFetchStage(Module):
fetch_pc = Signal(32, reset=reset_vector)
fetch_pc = Signal(32, reset=reset_vector)
- self.sync += output_pc.eq((fetch_action == `fetch_action_wait) ? output_pc : fetch_pc);
+ self.sync += If(fetch_action != fetch_action_wait,
+ output_pc.eq(fetch_pc)).
+ Else( output_pc.eq(output_pc)) # hmmm...
+ #self.sync += output_pc.eq((fetch_action == `fetch_action_wait) ?
+ # output_pc : fetch_pc);
memory_interface_fetch_address = fetch_pc[2:]
memory_interface_fetch_address = fetch_pc[2:]
@@
-67,32
+72,42
@@
class CPUFetchStage(Module):
self.sync += delayed_instruction.eq(output_instruction)
self.sync += output_state.eq(fetch_output_state_empty)
self.sync += delayed_instruction.eq(output_instruction)
self.sync += output_state.eq(fetch_output_state_empty)
- self.comb += output_instruction.eq(delayed_instruction_valid ? delayed_instruction : memory_interface_fetch_data)
+ self.comb += If(delayed_instruction_valid,
+ output_instruction.eq(delayed_instruction)
+ ).Else(
+ output_instruction.eq(memory_interface_fetch_data)
+ )
- self.sync += delayed_instruction_valid.eq(fetch_action == `fetch_action_wait)
+ self.sync += delayed_instruction_valid.eq(fetch_action ==
+ fetch_action_wait)
- fc = {}
- self.comb += Case(fetch_action, fc)
- fc[fetch_action_ack_trap] =
+ fc = {
+ fetch_action_ack_trap:
If(memory_interface_fetch_valid,
[fetch_pc.eq(fetch_pc + 4),
output_state.eq(fetch_output_state_valid)]
).Else(
[fetch_pc.eq(mtvec),
output_state.eq(fetch_output_state_trap)]
If(memory_interface_fetch_valid,
[fetch_pc.eq(fetch_pc + 4),
output_state.eq(fetch_output_state_valid)]
).Else(
[fetch_pc.eq(mtvec),
output_state.eq(fetch_output_state_trap)]
- )
- fc[fetch_action_default] = fc[fetch_action_ack_trap]
- fc[fetch_action_fence] =
+ ),
+ fetch_action_fence:
[ fetch_pc.eq(output_pc + 4),
[ fetch_pc.eq(output_pc + 4),
- output_state.eq(fetch_output_state_empty)]
- fc[fetch_action_jump] =
+ output_state.eq(fetch_output_state_empty)
+ ],
+ fetch_action_jump:
[ fetch_pc.eq(target_pc),
[ fetch_pc.eq(target_pc),
- output_state.eq(fetch_output_state_empty)]
- fc[fetch_action_error_trap] =
+ output_state.eq(fetch_output_state_empty)
+ ],
+ fetch_action_error_trap,
[fetch_pc.eq(mtvec),
[fetch_pc.eq(mtvec),
- output_state.eq(fetch_output_state_empty)
]
- fc[fetch_action_noerror_trap] = fc[fetch_action_error_trap]
- fc[fetch_action_wait] =
+ output_state.eq(fetch_output_state_empty)
+ ],
+ fetch_action_wait:
[fetch_pc.eq(fetch_pc),
[fetch_pc.eq(fetch_pc),
- output_state.eq(fetch_output_state_valid)]
+ output_state.eq(fetch_output_state_valid)
+ ]
+ }
+ fc[fetch_action_default] = fc[fetch_action_ack_trap]
+ fc[fetch_action_noerror_trap] = fc[fetch_action_error_trap]
+ self.sync += Case(fetch_action, fc).makedefault(fetch_action_default)