feat: Decode uarch ECALL and EBREAK

src/tests/machine-bind.lua

@@ -1114,4 +1114,48 @@ do_test("Test unhappy paths of verify_uarch_step_state_transition", function(mac
     assert_error("Mismatch in root hash of access 1", function(log) log.accesses[1].sibling_hashes[1] = bad_hash end)
 end)
 
+print("\n\n testing unsupported uarch instructions ")
+
+local uarch_ecall_program = {
+    0x00000073, -- ecall
+}
+
+local uarch_ebreak_program = {
+    0x00100073, -- ebreak
+}
+
+local uarch_illegal_insn_program = {
+    0x00000000, -- some illegal instruction
+}
+
+test_util.make_do_test(build_machine, machine_type, {
+    uarch = {
+        ram = { image_filename = test_util.create_test_uarch_program(uarch_ecall_program) },
+    },
+})("Detect unsupported ECALL instruction", function(machine)
+    local success, err = pcall(machine.run_uarch, machine)
+    assert(success == false)
+    assert(err:match("ECALL is not supported"))
+end)
+
+test_util.make_do_test(build_machine, machine_type, {
+    uarch = {
+        ram = { image_filename = test_util.create_test_uarch_program(uarch_ebreak_program) },
+    },
+})("Detect unsupported EBREAK instruction", function(machine)
+    local success, err = pcall(machine.run_uarch, machine)
+    assert(success == false)
+    assert(err:match("EBREAK is not supported"))
+end)
+
+test_util.make_do_test(build_machine, machine_type, {
+    uarch = {
+        ram = { image_filename = test_util.create_test_uarch_program(uarch_illegal_insn_program) },
+    },
+})("Detect illegal instruction", function(machine)
+    local success, err = pcall(machine.run_uarch, machine)
+    assert(success == false)
+    assert(err:match("illegal instruction"))
+end)
+
 print("\n\nAll machine binding tests for type " .. machine_type .. " passed")

src/uarch-step.cpp

@@ -1086,6 +1086,10 @@ static inline void executeInsn(UarchState &a, uint32 insn, uint64 pc) {
         return executeSLTI(a, insn, pc);
     } else if (insnMatchOpcodeFunct3(insn, 0xf, 0x0)) {
         return executeFENCE(a, insn, pc);
+    } else if (insn == uint32(0x73)) {
+        throw std::runtime_error("ECALL is not supported");
+    } else if (insn == uint32(0x100073)) {
+        throw std::runtime_error("EBREAK is not supported");
     }
     throw std::runtime_error("illegal instruction");
 }