From 50f77b702816502a2c19c279b98fad0d8193bfcf Mon Sep 17 00:00:00 2001
From: Adnan Ioricce <adnangonzagadevio@gmail.com>
Date: Fri, 11 Oct 2024 13:13:21 -0300
Subject: [PATCH] [Chapter15&VM] - adding a vm to run the instructions

---
 clox/chunk.h  |  5 ++++
 clox/common.h |  2 ++
 clox/debug.c  | 10 +++++++
 clox/main.c   | 16 +++++++++++
 clox/vm.c     | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++
 clox/vm.h     | 27 ++++++++++++++++++
 6 files changed, 136 insertions(+)
 create mode 100644 clox/vm.c
 create mode 100644 clox/vm.h

diff --git a/clox/chunk.h b/clox/chunk.h
index 466898b..2b3798f 100644
--- a/clox/chunk.h
+++ b/clox/chunk.h
@@ -7,6 +7,11 @@
 typedef enum {
   OP_CONSTANT,
   OP_RETURN,
+  OP_NEGATE,
+  OP_ADD,
+  OP_SUBTRACT,
+  OP_MULTIPLY,
+  OP_DIVIDE,
 } OpCode;
 
 typedef struct {
diff --git a/clox/common.h b/clox/common.h
index c827b76..ddab699 100644
--- a/clox/common.h
+++ b/clox/common.h
@@ -5,4 +5,6 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#define DEBUG_TRACE_EXECUTION
+
 #endif
diff --git a/clox/debug.c b/clox/debug.c
index eb86d7b..8f7af21 100644
--- a/clox/debug.c
+++ b/clox/debug.c
@@ -36,6 +36,16 @@ int disassembleInstruction(Chunk* chunk, int offset) {
   switch (instruction) {
     case OP_CONSTANT:
       return constantInstruction("OP_CONSTANT", chunk, offset);
+    case OP_ADD:
+      return simpleInstruction("OP_ADD", offset);
+    case OP_SUBTRACT:
+      return simpleInstruction("OP_SUBTRACT", offset);
+    case OP_MULTIPLY:
+      return simpleInstruction("OP_MULTIPLY", offset);
+    case OP_DIVIDE:
+      return simpleInstruction("OP_DIVIDE", offset);
+    case OP_NEGATE:
+      return simpleInstruction("OP_NEGATE", offset);
     case OP_RETURN:
       return simpleInstruction("OP_RETURN", offset);
     default:
diff --git a/clox/main.c b/clox/main.c
index 804bc90..99958b0 100644
--- a/clox/main.c
+++ b/clox/main.c
@@ -1,15 +1,31 @@
 #include "common.h"
 #include "chunk.h"
 #include "debug.h"
+#include "vm.h"
 int main(int argc,const char* argv[]){
+  initVM();
   Chunk chunk;
   initChunk(&chunk);
   int constant = addConstant(&chunk, 1.2);
   writeChunk(&chunk, OP_CONSTANT, 123);
   writeChunk(&chunk, constant, 123);
+  constant = addConstant(&chunk, 3.4);
+  writeChunk(&chunk, OP_CONSTANT, 123);
+  writeChunk(&chunk, constant, 123);
+
+  writeChunk(&chunk, OP_ADD, 123);
+
+  constant = addConstant(&chunk, 5.6);
+  writeChunk(&chunk, OP_CONSTANT, 123);
+  writeChunk(&chunk, constant, 123);
+
+  writeChunk(&chunk, OP_DIVIDE, 123);
+  writeChunk(&chunk, OP_NEGATE, 123);
 
   writeChunk(&chunk, OP_RETURN, 123);
   disassembleChunk(&chunk, "test chunk");
+  interpret(&chunk);
+  freeVM();
   freeChunk(&chunk);
   return 0;
 }
diff --git a/clox/vm.c b/clox/vm.c
new file mode 100644
index 0000000..4dcf6ae
--- /dev/null
+++ b/clox/vm.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include "common.h"
+#include "vm.h"
+#include "debug.h"
+VM vm; 
+static void resetStack() {
+  vm.stackTop = vm.stack;
+}
+void initVM() {
+  resetStack();
+}
+
+void freeVM() {
+
+}
+void push(Value value) {
+  *vm.stackTop = value;
+  vm.stackTop++;
+}
+Value pop() {
+  vm.stackTop--;
+  return *vm.stackTop;
+}
+
+static InterpretResult run() {
+#define READ_BYTE() (*vm.ip++)
+#define READ_CONSTANT() (vm.chunk->constants.values[READ_BYTE()])
+#define BINARY_OP(op) \
+    do { \
+      double b = pop(); \
+      double a = pop(); \
+      push(a op b); \
+    } while (false)
+  for (;;) {
+#ifdef DEBUG_TRACE_EXECUTION
+    printf("          ");
+    for (Value* slot = vm.stack; slot < vm.stackTop; slot++) {
+      printf("[ ");
+      printValue(*slot);
+      printf(" ]");
+    }
+    printf("\n");
+    disassembleInstruction(vm.chunk,
+                           (int)(vm.ip - vm.chunk->code));
+#endif
+    uint8_t instruction;
+    switch (instruction = READ_BYTE()) {
+      case OP_CONSTANT: {
+        Value constant = READ_CONSTANT();
+        printValue(constant);
+        printf("\n");
+        push(constant);
+        break;
+      }
+      case OP_NEGATE:   push(-pop()); break;
+      case OP_ADD:      BINARY_OP(+); break;
+      case OP_SUBTRACT: BINARY_OP(-); break;
+      case OP_MULTIPLY: BINARY_OP(*); break;
+      case OP_DIVIDE:   BINARY_OP(/); break;
+      case OP_RETURN: {
+        printValue(pop());
+        printf("\n");
+        return INTERPRET_OK;
+      }
+    }
+  }
+#undef READ_CONSTANT
+#undef BINARY_OP
+#undef READ_BYTE
+}
+InterpretResult interpret(Chunk* chunk) {
+  vm.chunk = chunk;
+  vm.ip = vm.chunk->code;
+  return run();
+}
+
diff --git a/clox/vm.h b/clox/vm.h
new file mode 100644
index 0000000..0df1cee
--- /dev/null
+++ b/clox/vm.h
@@ -0,0 +1,27 @@
+#ifndef clox_vm_h
+#define clox_vm_h
+
+#include "chunk.h"
+#include "value.h"
+
+#define STACK_MAX 256
+
+typedef struct {
+  Chunk* chunk;
+  uint8_t* ip;
+  Value stack[STACK_MAX];
+  Value* stackTop;
+} VM;
+typedef enum {
+  INTERPRET_OK,
+  INTERPRET_COMPILE_ERROR,
+  INTERPRET_RUNTIME_ERROR
+} InterpretResult;
+
+void initVM();
+void freeVM();
+InterpretResult interpret(Chunk* chunk);
+void push(Value value);
+Value pop();
+
+#endif