Add a simple boot section

example/Makefile

@@ -1,4 +1,6 @@
-example: example.c
+example: example.c Makefile boot.s linker.ld
-	riscv32-none-elf-gcc -fno-builtin -fvisibility=hidden -nostdlib -nostartfiles -march=rv32im -mabi=ilp32 -o example example.c -T linker.ld
+	riscv32-none-elf-as -march=rv32i -mabi=ilp32 boot.s -o boot.o
+	riscv32-none-elf-gcc -fno-builtin -fvisibility=hidden -nostdlib -nostartfiles -march=rv32im -mabi=ilp32 -c example.c -o example.o
+	riscv32-none-elf-ld boot.o example.o -T linker.ld -o example
 	riscv32-none-elf-strip -R .riscv.attributes example
 	riscv32-none-elf-strip -R .comment example

example/boot.s

@@ -0,0 +1,6 @@
+.globl _boot
+_boot:
+    lui x2, 0x80004
+    jal main
+    sbreak
+    j .

example/linker.ld

@@ -1,7 +1,7 @@
 ENTRY(_start)
 
 SECTIONS {
-    . = 0x1000;  /* Start address of the program */
+    . = 0x0000;  /* Start address of the program */
 
     .text : {
         *(.text)   /* Place all .text sections (code) here */

src/vm.cpp

@@ -23,7 +23,8 @@ void eval(uint8_t* memory, size_t memory_size) {
     return instruction;
   };
 
-  while (pc < memory_size) {
+  bool running = true;
+  while (pc < memory_size && running) {
     uint32_t instr = fetch_instruction();
     if (instr == 0) break;
     // std::cout << "pc: " << pc << "\n";
@@ -248,6 +249,10 @@ void eval(uint8_t* memory, size_t memory_size) {
       registers[rd] = pc + (imm << 12);  // Add the immediate (shifted left) to the current PC
       break;
     }
+    case 0x73: { // EBREAK
+      running = false; // Flag to stop the emulator
+      break;
+    }
     default:
       throw std::runtime_error("Unknown opcode");
     }