thumb32: Implement LDMDB/LDMEA

src/frontend/A32/decoder/thumb32.inc

@@ -6,7 +6,7 @@ INST(thumb32_STMIA,          "STMIA/STMEA",              "1110100010W0nnnn0iiiii
 INST(thumb32_LDMIA,          "LDMIA/LDMFD",              "1110100010W1nnnniiiiiiiiiiiiiiii")
 //INST(thumb32_PUSH,           "PUSH",                     "1110100100101101----------------")
 INST(thumb32_STMDB,          "STMDB/STMFD",              "1110100100W0nnnn0iiiiiiiiiiiiiii")
-//INST(thumb32_LDMDB,          "LDMDB/LDMEA",              "1110100100-1--------------------")
+INST(thumb32_LDMDB,          "LDMDB/LDMEA",              "1110100100W1nnnniiiiiiiiiiiiiiii")
 //INST(thumb32_SRS_1,          "SRS",                      "1110100110-0--------------------")
 //INST(thumb32_RFE_2,          "RFE",                      "1110100110-1--------------------")
 

src/frontend/A32/translate/impl/thumb32_load_store_multiple.cpp

@@ -51,6 +51,31 @@ static bool STMHelper(A32::IREmitter& ir, bool W, Reg n, u32 list,
     return true;
 }
 
+bool ThumbTranslatorVisitor::thumb32_LDMDB(bool W, Reg n, Imm<16> reg_list) {
+    const auto regs_imm = reg_list.ZeroExtend();
+    const auto num_regs = static_cast<u32>(Common::BitCount(regs_imm));
+
+    if (n == Reg::PC || num_regs < 2) {
+        return UnpredictableInstruction();
+    }
+    if (reg_list.Bit<15>() && reg_list.Bit<14>()) {
+        return UnpredictableInstruction();
+    }
+    if (W && Common::Bit(static_cast<size_t>(n), regs_imm)) {
+        return UnpredictableInstruction();
+    }
+    if (reg_list.Bit<13>()) {
+        return UnpredictableInstruction();
+    }
+    if (reg_list.Bit<15>() && ITBlockCheck(ir)) {
+        return UnpredictableInstruction();
+    }
+
+    // Start address is the same as the writeback address.
+    const IR::U32 start_address = ir.Sub(ir.GetRegister(n), ir.Imm32(4 * num_regs));
+    return LDMHelper(ir, W, n, regs_imm, start_address, start_address);
+}
+
 bool ThumbTranslatorVisitor::thumb32_LDMIA(bool W, Reg n, Imm<16> reg_list) {
     const auto regs_imm = reg_list.ZeroExtend();
     const auto num_regs = static_cast<u32>(Common::BitCount(regs_imm));

src/frontend/A32/translate/impl/translate_thumb.h

@@ -172,6 +172,7 @@ struct ThumbTranslatorVisitor final {
     bool thumb16_B_t2(Imm<11> imm11);
 
     // thumb32 load/store multiple instructions
+    bool thumb32_LDMDB(bool W, Reg n, Imm<16> reg_list);
     bool thumb32_LDMIA(bool W, Reg n, Imm<16> reg_list);
     bool thumb32_STMIA(bool W, Reg n, Imm<15> reg_list);
     bool thumb32_STMDB(bool W, Reg n, Imm<15> reg_list);