From f3b18ead59ae02f95dabbf0a1dea40873a816975 Mon Sep 17 00:00:00 2001
From: Alejandro Soto <alejandro@34project.org>
Date: Sun, 21 Jan 2024 06:23:46 -0600
Subject: rtl: refactor filenames and directory hierarchy

---
 rtl/core/core_control_psr.sv | 81 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 rtl/core/core_control_psr.sv

(limited to 'rtl/core/core_control_psr.sv')

diff --git a/rtl/core/core_control_psr.sv b/rtl/core/core_control_psr.sv
new file mode 100644
index 0000000..6616bc9
--- /dev/null
+++ b/rtl/core/core_control_psr.sv
@@ -0,0 +1,81 @@
+`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    exception_mode,
+
+	input  ctrl_cycle  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
+);
+
+	word exception_spsr;
+
+	assign psr_wb = psr_saved ? spsr_rd : cpsr_rd;
+
+	always_comb begin
+		psr_write = 0;
+
+		if(next_cycle.issue)
+			psr_write = final_psr_write || final_restore_spsr;
+
+		if(cycle.escalate || cycle.exception)
+			psr_write = 1;
+
+		if(cycle.escalate)
+			//TODO: F (FIQ) no cambia siempre
+			psr_wr = {24'b0, 3'b110, exception_mode};
+		else if(cycle.exception)
+			psr_wr = exception_spsr;
+		else
+			psr_wr = final_restore_spsr ? spsr_rd : alu_b;
+	end
+
+	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;
+
+			exception_spsr <= 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.escalate) begin
+			psr_saved <= 0;
+			psr_wr_flags <= 0;
+			psr_wr_control <= 1;
+			exception_spsr <= cpsr_rd;
+		end else if(next_cycle.exception) begin
+			psr <= 0;
+			psr_saved <= 1;
+			psr_wr_flags <= 1;
+		end else if(next_cycle.psr)
+			psr <= 0;
+
+endmodule
-- 
cgit v1.2.3