From 9bb39fe1350a39cbce516827835ec5a8a1adbe53 Mon Sep 17 00:00:00 2001
From: Michel Heily <michelheily@gmail.com>
Date: Fri, 15 May 2020 16:23:42 +0300
Subject: [PATCH] Fix gba-suite arm test #530

Fixes edge-case in STMDA with empty rlist


Former-commit-id: 5f43fa19e0faad7d27d022480d856ab0c52f1d56
Former-commit-id: 8e2392e1dd34fb161aa1b2c3445272f06f432316
---
 rustboyadvance-core/src/arm7tdmi/arm/exec.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/rustboyadvance-core/src/arm7tdmi/arm/exec.rs b/rustboyadvance-core/src/arm7tdmi/arm/exec.rs
index 50fb107..e00e282 100644
--- a/rustboyadvance-core/src/arm7tdmi/arm/exec.rs
+++ b/rustboyadvance-core/src/arm7tdmi/arm/exec.rs
@@ -626,9 +626,20 @@ impl Core {
                 self.reload_pipeline32(sb);
                 result = CpuAction::FlushPipeline;
             } else {
+                // block data store with empty rlist
+                let addr = match (ascending, full) {
+                    (false, false) => addr.wrapping_sub(0x3c),
+                    (false, true) => addr.wrapping_sub(0x40),
+                    (true, false) => addr,
+                    (true, true) => addr.wrapping_add(4),
+                };
                 self.write_32(addr, self.pc + 4, sb);
             }
-            addr = addr.wrapping_add(0x40);
+            addr = if ascending {
+                addr.wrapping_add(0x40)
+            } else {
+                addr.wrapping_sub(0x40)
+            };
         }
 
         if user_bank_transfer {