From f039d44ee383e80fa765fc42ccf9756f79e7f783 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Fri, 15 Sep 2023 22:08:20 -0400
Subject: [PATCH] Fully handle rm = 6, mod = 0.

---
 InstructionSets/x86/Decoder.cpp | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/InstructionSets/x86/Decoder.cpp b/InstructionSets/x86/Decoder.cpp
index 6dd089236..9459fd974 100644
--- a/InstructionSets/x86/Decoder.cpp
+++ b/InstructionSets/x86/Decoder.cpp
@@ -640,6 +640,10 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
 				operation_ == Operation::LFS) {
 				undefined();
 			}
+		} else if(rm == 6 && mod == 0) {
+			// There's no BP direct; BP with ostensibly no offset means 'direct address' mode.
+			displacement_size_ = data_size(address_size_);
+			memreg = Source::DirectAddress;
 		} else {
 			const DataSize sizes[] = {
 				DataSize::None,
@@ -670,11 +674,6 @@ std::pair<int, typename Decoder<model>::InstructionT> Decoder<model>::decode(con
 				};
 
 				sib_ = rm_table[rm];
-
-				// BP always gets a displacement.
-				if(rm == 6 && displacement_size_ == DataSize::None) {
-					displacement_size_ = DataSize::Word;
-				}
 			}
 		}