Add: Support for ECALL and EBREAK

Example/helloworld.s

@@ -0,0 +1,27 @@
+#
+# Risc-V Assembler program to print "Hello World!"
+# to stdout.
+#
+# a0-a2 - parameters to linux function services
+# a7 - linux function number
+#
+
+# Setup the parameters to print hello world
+# and then call Linux to do it.
+.text
+_start: 
+        addi  a0, x0, 1      # 1 = StdOut
+        la    a1, helloworld # load address of helloworld
+        addi  a2, x0, 13     # length of our string
+        addi  a7, x0, 64     # linux write system call
+        ecall                # Call linux to output the string
+
+# Setup the parameters to exit the program
+# and then call Linux to do it.
+
+        addi    a0, x0, 0   # Use 0 return code
+        addi    a7, x0, 93  # Service command code 93 terminates
+        ecall               # Call linux to terminate the program
+
+.data
+helloworld: .string "Hello World!\n"

SharpRISCV.Core/MachineCode/MachineCode.cs

@@ -80,6 +80,7 @@ private static int GetLoPart(string imm)
 
         public static int ProcessSource(string Immediate)
         {
+            if(Immediate == null) { return 0; }
 
             if (Immediate.StartsWith("%"))
             {

SharpRISCV.Core/Parser/Instruction/I_Parser.cs

@@ -59,6 +59,19 @@ public RiscVInstruction Parse(string instruction)
                 InstructionType = InstructionType.I,
             };
         }
+
+        if(instruction == "ecall" || instruction == "ebreak")
+        {
+            return new RiscVInstruction
+            {
+                Instruction = instruction,
+                Opcode = instruction,
+                Rd = string.Empty,
+                Rs1 = string.Empty,
+                InstructionType = InstructionType.I,
+            };
+        }
+
         return null;
     }
 }

SharpRISCV.Core/Registers/Register.cs

@@ -77,6 +77,7 @@ static Register()
             FromABI.Add("x29", 29);
             FromABI.Add("x30", 30);
             FromABI.Add("x31", 31);
+            FromABI.Add(string.Empty, 0);
         }
     }
 }

SharpRISCV.Core/RiscVAssembler.cs

@@ -267,6 +267,8 @@ public static InstructionType IdentifyInstructionType(string instruction)
                     return InstructionType.U;
                 case (OpCode)0b0010011:
                     return InstructionType.I;
+                case (OpCode)0b1110011:
+                    return InstructionType.I;
                 case (OpCode)0b1100011:
                     return InstructionType.B;
                 case (OpCode)0b0000011:

SharpRISCV.sln

@@ -17,11 +17,12 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Example", "Example", "{2730FC94-0E0E-4CD7-870B-27E1D55C9B27}"
 	ProjectSection(SolutionItems) = preProject
 		Example\example.s = Example\example.s
+		helloworld.s = helloworld.s
 	EndProjectSection
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WebRISCV", "WebRISCV\WebRISCV.csproj", "{E4C78F51-2521-41A5-BBC2-8ABCE9B9975B}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "WebRISCV", "WebRISCV\WebRISCV.csproj", "{E4C78F51-2521-41A5-BBC2-8ABCE9B9975B}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SharpRISCV.Core", "SharpRISCV.Core\SharpRISCV.Core.csproj", "{4532AF82-E17D-4B81-B311-58C78096900A}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "SharpRISCV.Core", "SharpRISCV.Core\SharpRISCV.Core.csproj", "{4532AF82-E17D-4B81-B311-58C78096900A}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution