[otbn] Small decode fixes and struct rearrangement
This places far more of the decoder signals into the specific
base/bignum structs. Those signals that are moved into the specific
structs may have had a shared meaning but are unrelated in terms of
logic (e.g. operand select for the ALUs, different decode logic for
bignum and base ISAs and different ALU muxes they control).
There are some small clean-ups around removing unused types and enums
that relate to decode.
Signed-off-by: Greg Chadwick <gac@lowrisc.org>
diff --git a/hw/ip/otbn/rtl/otbn_controller.sv b/hw/ip/otbn/rtl/otbn_controller.sv
index 9adc7e4..d962c2e 100644
--- a/hw/ip/otbn/rtl/otbn_controller.sv
+++ b/hw/ip/otbn/rtl/otbn_controller.sv
@@ -207,7 +207,7 @@
// Base ALU Operand A MUX
always_comb begin
- unique case (insn_dec_shared_i.op_a_sel)
+ unique case (insn_dec_base_i.op_a_sel)
OpASelRegister:
alu_base_operation_o.operand_a = rf_base_rd_data_a_i;
OpASelZero:
@@ -221,7 +221,7 @@
// Base ALU Operand B MUX
always_comb begin
- unique case (insn_dec_shared_i.op_b_sel)
+ unique case (insn_dec_base_i.op_b_sel)
OpBSelRegister:
alu_base_operation_o.operand_b = rf_base_rd_data_b_i;
OpBSelImmediate:
@@ -240,15 +240,13 @@
// Register file write MUX
// Suppress write for loads when controller isn't in stall state as load data for writeback is
// only available in the stall state.
- assign rf_base_wr_en_o =
- insn_dec_shared_i.rf_we &
- ~(insn_dec_shared_i.ld_insn & (state_q != OtbnStateStall)) &
- (insn_dec_shared_i.subset == InsnSubsetBase);
+ assign rf_base_wr_en_o = insn_dec_base_i.rf_we &
+ ~(insn_dec_shared_i.ld_insn & (state_q != OtbnStateStall));
assign rf_base_wr_addr_o = insn_dec_base_i.d;
always_comb begin
- unique case (insn_dec_shared_i.rf_wdata_sel)
+ unique case (insn_dec_base_i.rf_wdata_sel)
RfWdSelEx:
rf_base_wr_data_o = alu_base_operation_result_i;
RfWdSelLsu:
@@ -269,7 +267,7 @@
// Base ALU Operand B MUX
always_comb begin
- unique case (insn_dec_shared_i.op_b_sel)
+ unique case (insn_dec_bignum_i.op_b_sel)
OpBSelRegister:
alu_bignum_operation_o.operand_b = rf_bignum_rd_data_b_i;
OpBSelImmediate:
@@ -288,15 +286,12 @@
// Suppress write for loads when controller isn't in stall state as load data for writeback is
// only available in the stall state.
assign rf_bignum_wr_en_o =
- {2{insn_dec_shared_i.rf_we &
- ~(insn_dec_shared_i.ld_insn & (state_q != OtbnStateStall)) &
- (insn_dec_shared_i.subset == InsnSubsetBignum)
- }};
+ {2{insn_dec_bignum_i.rf_we & ~(insn_dec_shared_i.ld_insn & (state_q != OtbnStateStall))}};
assign rf_bignum_wr_addr_o = insn_dec_bignum_i.d;
always_comb begin
- unique case (insn_dec_shared_i.rf_wdata_sel)
+ unique case (insn_dec_bignum_i.rf_wdata_sel)
RfWdSelEx:
rf_bignum_wr_data_o = alu_bignum_operation_result_i;
RfWdSelLsu:
