thumb32: Implement STREX variants

Implements the exclusive store instructions. Now all that remains for
ARMv7 load/stores to be done is the exclusive loads.

src/frontend/A32/decoder/thumb32.inc

@@ -11,7 +11,7 @@ INST(thumb32_LDMDB,          "LDMDB/LDMEA",              "1110100100W1nnnniiiiii
 //INST(thumb32_RFE_2,          "RFE",                      "1110100110-1--------------------")
 
 // Load/Store Dual, Load/Store Exclusive, Table Branch
-//INST(thumb32_STREX,          "STREX",                    "111010000100--------------------")
+INST(thumb32_STREX,          "STREX",                    "111010000100nnnnttttddddiiiiiiii")
 //INST(thumb32_LDREX,          "LDREX",                    "111010000101--------------------")
 INST(thumb32_STRD_imm_1,     "STRD (imm)",               "11101000U110nnnnttttssssiiiiiiii")
 INST(thumb32_STRD_imm_2,     "STRD (imm)",               "11101001U1W0nnnnttttssssiiiiiiii")
@@ -19,9 +19,9 @@ INST(thumb32_LDRD_lit_1,     "LDRD (lit)",               "11101000U1111111ttttss
 INST(thumb32_LDRD_lit_2,     "LDRD (lit)",               "11101001U1W11111ttttssssiiiiiiii")
 INST(thumb32_LDRD_imm_1,     "LDRD (imm)",               "11101000U111nnnnttttssssiiiiiiii")
 INST(thumb32_LDRD_imm_2,     "LDRD (imm)",               "11101001U1W1nnnnttttssssiiiiiiii")
-//INST(thumb32_STREXB,         "STREXB",                   "111010001100------------0100----")
+INST(thumb32_STREXB,         "STREXB",                   "111010001100nnnntttt11110100dddd")
-//INST(thumb32_STREXH,         "STREXH",                   "111010001100------------0101----")
+INST(thumb32_STREXH,         "STREXH",                   "111010001100nnnntttt11110101dddd")
-//INST(thumb32_STREXD,         "STREXD",                   "111010001100------------0111----")
+INST(thumb32_STREXD,         "STREXD",                   "111010001100nnnnttttuuuu0111dddd")
 INST(thumb32_TBB,            "TBB",                      "111010001101nnnn111100000000mmmm")
 INST(thumb32_TBH,            "TBH",                      "111010001101nnnn111100000001mmmm")
 //INST(thumb32_LDREXB,         "LDREXB",                   "111010001101------------0100----")

src/frontend/A32/translate/impl/thumb32_load_store_dual.cpp

@@ -135,6 +135,67 @@ bool ThumbTranslatorVisitor::thumb32_STRD_imm_2(bool U, bool W, Reg n, Reg t, Re
     return StoreDual(*this, true, U, W, n, t, t2, imm8);
 }
 
+bool ThumbTranslatorVisitor::thumb32_STREX(Reg n, Reg t, Reg d, Imm<8> imm8) {
+    if (d == Reg::PC || t == Reg::PC || n == Reg::PC) {
+        return UnpredictableInstruction();
+    }
+    if (d == n || d == t) {
+        return UnpredictableInstruction();
+    }
+
+    const auto address = ir.Add(ir.GetRegister(n), ir.Imm32(imm8.ZeroExtend()));
+    const auto value = ir.GetRegister(t);
+    const auto passed = ir.ExclusiveWriteMemory32(address, value);
+    ir.SetRegister(d, passed);
+    return true;
+}
+
+bool ThumbTranslatorVisitor::thumb32_STREXB(Reg n, Reg t, Reg d) {
+    if (d == Reg::PC || t == Reg::PC || n == Reg::PC) {
+        return UnpredictableInstruction();
+    }
+    if (d == n || d == t) {
+        return UnpredictableInstruction();
+    }
+
+    const auto address = ir.GetRegister(n);
+    const auto value = ir.LeastSignificantByte(ir.GetRegister(t));
+    const auto passed = ir.ExclusiveWriteMemory8(address, value);
+    ir.SetRegister(d, passed);
+    return true;
+}
+
+bool ThumbTranslatorVisitor::thumb32_STREXD(Reg n, Reg t, Reg t2, Reg d) {
+    if (d == Reg::PC || t == Reg::PC || t2 == Reg::PC || n == Reg::PC) {
+        return UnpredictableInstruction();
+    }
+    if (d == n || d == t || d == t2) {
+        return UnpredictableInstruction();
+    }
+
+    const auto address = ir.GetRegister(n);
+    const auto value_lo = ir.GetRegister(t);
+    const auto value_hi = ir.GetRegister(t2);
+    const auto passed = ir.ExclusiveWriteMemory64(address, value_lo, value_hi);
+    ir.SetRegister(d, passed);
+    return true;
+}
+
+bool ThumbTranslatorVisitor::thumb32_STREXH(Reg n, Reg t, Reg d) {
+    if (d == Reg::PC || t == Reg::PC || n == Reg::PC) {
+        return UnpredictableInstruction();
+    }
+    if (d == n || d == t) {
+        return UnpredictableInstruction();
+    }
+
+    const auto address = ir.GetRegister(n);
+    const auto value = ir.LeastSignificantHalf(ir.GetRegister(t));
+    const auto passed = ir.ExclusiveWriteMemory16(address, value);
+    ir.SetRegister(d, passed);
+    return true;
+}
+
 bool ThumbTranslatorVisitor::thumb32_TBB(Reg n, Reg m) {
     return TableBranch(*this, n, m, false);
 }

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

@@ -186,6 +186,10 @@ struct ThumbTranslatorVisitor final {
     bool thumb32_LDRD_lit_2(bool U, bool W, Reg t, Reg t2, Imm<8> imm8);
     bool thumb32_STRD_imm_1(bool U, Reg n, Reg t, Reg t2, Imm<8> imm8);
     bool thumb32_STRD_imm_2(bool U, bool W, Reg n, Reg t, Reg t2, Imm<8> imm8);
+    bool thumb32_STREX(Reg n, Reg t, Reg d, Imm<8> imm8);
+    bool thumb32_STREXB(Reg n, Reg t, Reg d);
+    bool thumb32_STREXD(Reg n, Reg t, Reg t2, Reg d);
+    bool thumb32_STREXH(Reg n, Reg t, Reg d);
     bool thumb32_TBB(Reg n, Reg m);
     bool thumb32_TBH(Reg n, Reg m);
 

tests/A32/fuzz_arm.cpp

@@ -166,6 +166,12 @@ std::vector<u16> GenRandomThumbInst(u32 pc, bool is_last_inst, A32::ITState it_s
             "thumb16_BKPT",
             "thumb16_IT",
             "thumb16_SETEND",
+
+            // Exclusive load/stores
+            "thumb32_STREX",
+            "thumb32_STREXB",
+            "thumb32_STREXD",
+            "thumb32_STREXH",
         };
 
         for (const auto& [fn, bitstring] : list) {