From 1ca30fb3de058b9498f6a6bbc646b79978ece846 Mon Sep 17 00:00:00 2001
From: Alejandro Soto <alejandro@34project.org>
Date: Mon, 17 Oct 2022 01:25:42 -0600
Subject: Break false dependency on r0 for MOV/MVN

---
 rtl/core/decode/data.sv | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

(limited to 'rtl/core/decode/data.sv')

diff --git a/rtl/core/decode/data.sv b/rtl/core/decode/data.sv
index cb21f5e..103fb14 100644
--- a/rtl/core/decode/data.sv
+++ b/rtl/core/decode/data.sv
@@ -10,7 +10,8 @@ module core_decode_data
 	                   snd_shift_by_reg_if_reg,
 	                   writeback,
 	                   update_flags,
-	                   restore_spsr
+	                   restore_spsr,
+	                   uses_rn
 );
 
 	alu_op op;
@@ -35,6 +36,14 @@ module core_decode_data
 				writeback = 1;
 		endcase
 
+		unique case(op)
+			`ALU_MOV, `ALU_MVN:
+				uses_rn = 0;
+
+			default:
+				uses_rn = 1;
+		endcase
+
 		update_flags = insn `FIELD_DATA_S;
 		restore_spsr = (rd == `R15) & update_flags;
 
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