1 files changed, 90 insertions, 0 deletions
diff --git a/rtl/core/decode/data.sv b/rtl/core/decode/data.sv
new file mode 100644
index 0000000..7958631
--- /dev/null
+++ b/rtl/core/decode/data.sv
@@ -0,0 +1,90 @@
+`include "core/isa.sv"
+`include "core/psr.sv"
+`include "core/uarch.sv"
+
+module core_decode_data
+(
+	input  logic[31:0] insn,
+	input  psr_flags   flags,
+
+	output alu_op      op,
+	output reg_num     rn,
+	                   rd,
+	output logic       writeback,
+	                   update_flags,
+	                   restore_spsr,
+	                   zero_fst,
+	                   negate_fst,
+	                   negate_snd,
+	                   carry_in
+);
+
+	assign rn = insn `FIELD_DATA_RN;
+	assign rd = insn `FIELD_DATA_RD;
+
+	always_comb begin
+		update_flags = insn `FIELD_DATA_S;
+		writeback = 1;
+
+		op = ALU_ADD;
+		zero_fst = 0;
+		negate_fst = 0;
+		negate_snd = 0;
+		carry_in = 0;
+
+		unique case(insn `FIELD_DATA_OPCODE)
+			`DATA_ADD: ;
+
+			`DATA_AND: op = ALU_AND;
+			`DATA_EOR: op = ALU_XOR;
+			`DATA_ORR: op = ALU_ORR;
+			`DATA_SUB: negate_snd = 1;
+			`DATA_RSB: negate_fst = 1;
+			`DATA_ADC: carry_in = flags.c;
+			`DATA_MOV: zero_fst = 1;
+			`DATA_CMN: writeback = 0;
+
+			`DATA_MVN: begin
+				zero_fst = 1;
+				negate_snd = 1;
+			end
+
+			`DATA_SBC: begin
+				negate_snd = 1;
+				carry_in = flags.c;
+			end
+
+			`DATA_RSC: begin
+				negate_fst = 1;
+				carry_in = flags.c;
+			end
+
+			`DATA_BIC: begin
+				op = ALU_AND;
+				negate_snd = 1;
+				carry_in = 1;
+			end
+
+			`DATA_TST: begin
+				op = ALU_AND;
+				writeback = 0;
+			end
+
+			`DATA_TEQ: begin
+				op = ALU_XOR;
+				writeback = 0;
+			end
+
+			`DATA_CMP: begin
+				writeback = 0;
+				negate_snd = 1;
+			end
+
+		endcase
+
+		restore_spsr = (rd == `R15) & update_flags;
+		if(restore_spsr)
+			update_flags = 0;
+	end
+
+endmodule