Implement psr read/write logic

1 files changed, 56 insertions, 0 deletions

diff --git a/rtl/core/control/psr.sv b/rtl/core/control/psr.sv
new file mode 100644
index 0000000..758b730
--- /dev/null
+++ b/rtl/core/control/psr.sv
@@ -0,0 +1,56 @@
+`include "core/uarch.sv"
+
+module core_control_psr
+(
+	input  logic       clk,
+	                   rst_n,
+
+	input  insn_decode dec,
+	input  word        cpsr_rd,
+	                   spsr_rd,
+	                   alu_b,
+	input  psr_mode    mode,
+
+	input  ctrl_cycle  next_cycle,
+	input  logic       issue,
+
+	output logic       psr,
+	                   psr_saved,
+	                   psr_write,
+	                   psr_wr_flags,
+	                   psr_wr_control,
+	                   final_psr_write,
+	                   final_restore_spsr,
+	output word        psr_wb,
+	                   psr_wr,
+	output psr_mode    reg_mode
+);
+
+	assign psr_wb = psr_saved ? spsr_rd : cpsr_rd;
+	assign psr_wr = final_restore_spsr ? spsr_rd : alu_b;
+	assign psr_write = next_cycle.issue && (final_psr_write || final_restore_spsr);
+
+	//TODO: casos donde esto no es cierto
+	assign reg_mode = mode;
+
+	always_ff @(posedge clk or negedge rst_n)
+		if(!rst_n) begin
+			psr <= 0;
+			psr_saved <= 0;
+			psr_wr_flags <= 0;
+			psr_wr_control <= 0;
+
+			final_psr_write <= 0;
+			final_restore_spsr <= 0;
+		end else if(next_cycle.issue) begin
+			psr <= issue && dec.ctrl.psr;
+			psr_saved <= dec.psr.saved;
+			psr_wr_flags <= dec.psr.wr_flags;
+			psr_wr_control <= dec.psr.wr_control;
+
+			final_psr_write <= issue && dec.psr.write;
+			final_restore_spsr <= issue && dec.psr.restore_spsr;
+		end else if(next_cycle.psr)
+			psr <= 0;
+
+endmodule