thumb32: Implement QSUB8/UQSUB8

src/frontend/A32/decoder/thumb32.h

@@ -246,7 +246,7 @@ std::optional<std::reference_wrapper<const Thumb32Matcher<V>>> DecodeThumb32(u32
         INST(&V::thumb32_QSAX,           "QSAX",                     "111110101110nnnn1111dddd0001mmmm"),
         INST(&V::thumb32_QSUB16,         "QSUB16",                   "111110101101nnnn1111dddd0001mmmm"),
         INST(&V::thumb32_QADD8,          "QADD8",                    "111110101000nnnn1111dddd0001mmmm"),
-        //INST(&V::thumb32_QSUB8,          "QSUB8",                    "111110101100----1111----0001----"),
+        INST(&V::thumb32_QSUB8,          "QSUB8",                    "111110101100nnnn1111dddd0001mmmm"),
         //INST(&V::thumb32_SHADD16,        "SHADD16",                  "111110101001----1111----0010----"),
         //INST(&V::thumb32_SHASX,          "SHASX",                    "111110101010----1111----0010----"),
         //INST(&V::thumb32_SHSAX,          "SHSAX",                    "111110101110----1111----0010----"),
@@ -266,7 +266,7 @@ std::optional<std::reference_wrapper<const Thumb32Matcher<V>>> DecodeThumb32(u32
         INST(&V::thumb32_UQSAX,          "UQSAX",                    "111110101110nnnn1111dddd0101mmmm"),
         INST(&V::thumb32_UQSUB16,        "UQSUB16",                  "111110101101nnnn1111dddd0101mmmm"),
         INST(&V::thumb32_UQADD8,         "UQADD8",                   "111110101000nnnn1111dddd0101mmmm"),
-        //INST(&V::thumb32_UQSUB8,         "UQSUB8",                   "111110101100----1111----0101----"),
+        INST(&V::thumb32_UQSUB8,         "UQSUB8",                   "111110101100nnnn1111dddd0101mmmm"),
         //INST(&V::thumb32_UHADD16,        "UHADD16",                  "111110101001----1111----0110----"),
         //INST(&V::thumb32_UHASX,          "UHASX",                    "111110101010----1111----0110----"),
         //INST(&V::thumb32_UHSAX,          "UHSAX",                    "111110101110----1111----0110----"),

src/frontend/A32/translate/impl/thumb32_parallel.cpp

@@ -246,6 +246,19 @@ bool ThumbTranslatorVisitor::thumb32_QSAX(Reg n, Reg d, Reg m) {
     return true;
 }
 
+bool ThumbTranslatorVisitor::thumb32_QSUB8(Reg n, Reg d, Reg m) {
+    if (d == Reg::PC || n == Reg::PC || m == Reg::PC) {
+        return UnpredictableInstruction();
+    }
+
+    const auto reg_m = ir.GetRegister(m);
+    const auto reg_n = ir.GetRegister(n);
+    const auto result = ir.PackedSaturatedSubS8(reg_n, reg_m);
+
+    ir.SetRegister(d, result);
+    return true;
+}
+
 bool ThumbTranslatorVisitor::thumb32_QSUB16(Reg n, Reg d, Reg m) {
     if (d == Reg::PC || n == Reg::PC || m == Reg::PC) {
         return UnpredictableInstruction();
@@ -323,6 +336,19 @@ bool ThumbTranslatorVisitor::thumb32_UQSAX(Reg n, Reg d, Reg m) {
     return true;
 }
 
+bool ThumbTranslatorVisitor::thumb32_UQSUB8(Reg n, Reg d, Reg m) {
+    if (d == Reg::PC || n == Reg::PC || m == Reg::PC) {
+        return UnpredictableInstruction();
+    }
+
+    const auto reg_m = ir.GetRegister(m);
+    const auto reg_n = ir.GetRegister(n);
+    const auto result = ir.PackedSaturatedSubU8(reg_n, reg_m);
+
+    ir.SetRegister(d, result);
+    return true;
+}
+
 bool ThumbTranslatorVisitor::thumb32_UQSUB16(Reg n, Reg d, Reg m) {
     if (d == Reg::PC || n == Reg::PC || m == Reg::PC) {
         return UnpredictableInstruction();

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

@@ -146,11 +146,13 @@ struct ThumbTranslatorVisitor final {
     bool thumb32_QADD16(Reg n, Reg d, Reg m);
     bool thumb32_QASX(Reg n, Reg d, Reg m);
     bool thumb32_QSAX(Reg n, Reg d, Reg m);
+    bool thumb32_QSUB8(Reg n, Reg d, Reg m);
     bool thumb32_QSUB16(Reg n, Reg d, Reg m);
     bool thumb32_UQADD8(Reg n, Reg d, Reg m);
     bool thumb32_UQADD16(Reg n, Reg d, Reg m);
     bool thumb32_UQASX(Reg n, Reg d, Reg m);
     bool thumb32_UQSAX(Reg n, Reg d, Reg m);
+    bool thumb32_UQSUB8(Reg n, Reg d, Reg m);
     bool thumb32_UQSUB16(Reg n, Reg d, Reg m);
 };
 

tests/A32/fuzz_thumb.cpp

@@ -392,6 +392,8 @@ TEST_CASE("Fuzz Thumb32 instructions set", "[JitX64][Thumb][Thumb32]") {
                      three_reg_not_r15),
         ThumbInstGen("111110101000nnnn1111dddd1010mmmm", // QSUB
                      three_reg_not_r15),
+        ThumbInstGen("111110101100nnnn1111dddd0001mmmm", // QSUB8
+                     three_reg_not_r15),
         ThumbInstGen("111110101101nnnn1111dddd0001mmmm", // QSUB16
                      three_reg_not_r15),
         ThumbInstGen("111110101001nnnn1111dddd1010mmmm", // RBIT
@@ -450,6 +452,8 @@ TEST_CASE("Fuzz Thumb32 instructions set", "[JitX64][Thumb][Thumb32]") {
                      three_reg_not_r15),
         ThumbInstGen("111110101110nnnn1111dddd0101mmmm", // UQSAX
                      three_reg_not_r15),
+        ThumbInstGen("111110101100nnnn1111dddd0101mmmm", // UQSUB8
+                     three_reg_not_r15),
         ThumbInstGen("111110101101nnnn1111dddd0101mmmm", // UQSUB16
                      three_reg_not_r15),
         ThumbInstGen("111110101110nnnn1111dddd0100mmmm", // USAX