From f5aa73e7cae0c5f8e6f5a099587736c80624120b Mon Sep 17 00:00:00 2001
From: Amneesh Singh <natto@weirdnatto.in>
Date: Wed, 19 Jun 2024 14:18:37 +0530
Subject: [PATCH] cpu/thumb: fix multiple load/store

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>
---
 src/cpu/thumb/exec.cc   | 4 ++--
 tests/cpu/thumb/exec.cc | 9 +++++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/cpu/thumb/exec.cc b/src/cpu/thumb/exec.cc
index 4123316..f26186e 100644
--- a/src/cpu/thumb/exec.cc
+++ b/src/cpu/thumb/exec.cc
@@ -499,10 +499,10 @@ Instruction::exec(Cpu& cpu) {
                     }
                 }
             } else {
-                for (int8_t i = 7; i >= 0; i--) {
+                for (uint8_t i = 0; i < 8; i++) {
                     if (get_bit(data.regs, i)) {
-                        rb -= alignment;
                         cpu.bus->write_word(rb, cpu.gpr[i], sequential);
+                        rb += alignment;
                         sequential = true;
                     }
                 }
diff --git a/tests/cpu/thumb/exec.cc b/tests/cpu/thumb/exec.cc
index b98d686..aa056a4 100644
--- a/tests/cpu/thumb/exec.cc
+++ b/tests/cpu/thumb/exec.cc
@@ -855,18 +855,19 @@ TEST_CASE_METHOD(CpuFixture, "Multiple Load/Store", TAG) {
         setr(6, 131313333);
         setr(7, 131);
 
-        // set R2 (base) to top of stack
-        setr(2, address + alignment * 5);
+        // base
+        setr(2, address);
 
         exec(data);
 
         CHECK(bus->read_word(address) == 237164);
-        CHECK(bus->read_word(address + alignment) == address + alignment * 5);
+        CHECK(bus->read_word(address + alignment) == address);
         CHECK(bus->read_word(address + alignment * 2) == 905895898);
         CHECK(bus->read_word(address + alignment * 3) == 131313333);
         CHECK(bus->read_word(address + alignment * 4) == 131);
+
         // write back
-        CHECK(getr(2) == address);
+        CHECK(getr(2) == address + alignment * 5);
     }
 
     SECTION("load") {