hardcoded string implementation

arch/linux/tui/main.c

@@ -2,16 +2,18 @@
 #include "../../../tools/compiler/compiler.h"
 #include <stdio.h>
 
-#define CODE_SIZE 8192
 #define MEMORY_SIZE 65536
+#define CODE_SIZE 8192
+#define STACK_SIZE 1024
+
 u8 lmem[MEMORY_SIZE] = {0};
 u8 lcode[CODE_SIZE] = {0};
-u32 lstack[CODE_SIZE] = {0};
+u32 lstack[STACK_SIZE] = {0};
 
 void reset() {
   pc = 0;
   cp = 0;
-  mp = 0;
+  mp = 255; // hardcoded for now, 255 locals
   fp = 0;
   sp = 0;
   interrupt = 0;
@@ -84,6 +86,8 @@ static void repl() {
 
     while(step_vm()) {}
     
+    syscall(SYSCALL_CONSOLE_WRITE, 255);
+
     printf("Result at top of stack: %d\n", stack[0]);
   }
 }

tools/compiler/compiler.c

@@ -277,7 +277,7 @@ static void binary() {
     code[cp++] = OP_DIV_INT;
     break;
   }
-  case TOKEN_EQ_EQ:{
+  case TOKEN_EQ_EQ: {
     code[cp++] = OP_EQ;
     break;
   }
@@ -324,6 +324,49 @@ static void literal() {
   }
 }
 
+static void string() {
+  u32 addr = mp;
+  const char *src = parser.previous.start + 1;
+  i32 len = 0;
+  i32 i = 0;
+
+  while (i < parser.previous.length - 2) {
+    char c = src[i++];
+    if (c == '\\' && i < parser.previous.length - 2) {
+      switch (src[i++]) {
+      case 'n':
+        c = '\n';
+        break;
+      case 't':
+        c = '\t';
+        break;
+      case 'r':
+        c = '\r';
+        break;
+      case '\\':
+      case '"':
+      case '\'':
+        break;
+      default:
+        i--; /* Rewind for unknown escapes */
+      }
+    }
+    WRITE_U8(addr + 4 + len, c);
+    len++;
+  }
+
+  u32 size = len + 5; /* 4 (len) + dst_len + 1 (null) */
+  mp += size;
+
+  WRITE_U32(addr, len);
+  WRITE_U8(addr + 4 + len, '\0');
+
+  // TODO: this really should always be tied to a global or local variable
+  // we can fake it for now
+  WRITE_U32(fp + lp, addr);
+  lp++;
+}
+
 ParseRule rules[] = {
     [TOKEN_LPAREN] = {grouping, NULL, PREC_NONE},
     [TOKEN_RPAREN] = {NULL, NULL, PREC_NONE},
@@ -345,7 +388,7 @@ ParseRule rules[] = {
     [TOKEN_LT] = {NULL, binary, PREC_COMPARISON},
     [TOKEN_LTE] = {NULL, binary, PREC_COMPARISON},
     [TOKEN_IDENTIFIER] = {NULL, NULL, PREC_NONE},
-    [TOKEN_LITERAL_STR] = {NULL, NULL, PREC_NONE},
+    [TOKEN_LITERAL_STR] = {string, NULL, PREC_NONE},
     [TOKEN_LITERAL_INT] = {number, NULL, PREC_NONE},
     [TOKEN_LITERAL_NAT] = {number, NULL, PREC_NONE},
     [TOKEN_LITERAL_REAL] = {number, NULL, PREC_NONE},
@@ -395,5 +438,8 @@ bool compile(ScopeTable *st, char *source) {
   expression();
   consume(TOKEN_EOF, "Cannot find end of expression.");
 
-  return false;
+  // technically should not need, but just in case
+  code[cp++] = OP_HALT;
+
+  return true;
 }

vm/vm.c

@@ -5,7 +5,8 @@ u32 pc;        /* program counter */
 u32 cp;        /* code pointer */
 u32 mp;        /* memory pointer */
 u32 fp;        /* frame pointer */
-u32 sp;        /* frame pointer */
+u32 sp;        /* stack pointer */
+u8  lp;        /* locals pointer */
 u8  status;    /* status flag */
 u8  interrupt; /* device interrupt */
 u32 *stack;    /* stack */
@@ -388,6 +389,11 @@ bool step_vm() {
     stack[sp++] = result;
     return true;
   }
+  case OP_NOT: {
+    u32 a = !stack[--sp];
+    stack[sp++] = a;
+    return true;
+  }
   case OP_BIT_SHIFT_LEFT: {
     MATH_OP_NO_CAST(<<);
   }
@@ -406,11 +412,6 @@ bool step_vm() {
   case OP_BIT_XOR: {
     MATH_OP_NO_CAST(^);
   }
-  case OP_NOT: {
-    u32 a = !stack[--sp];
-    stack[sp++] = a;
-    return true;
-  }
   case OP_EQ: {
     MATH_OP_NO_CAST(==);
   }

vm/vm.h

@@ -96,6 +96,7 @@ extern u32 cp;           /* code pointer */
 extern u32 mp;           /* memory pointer */
 extern u32 fp;           /* frame pointer */
 extern u32 sp;           /* stack pointer */
+extern u8  lp;           /* locals pointer */
 extern u8 status;        /* status flag */
 extern u8 interrupt;     /* device interrupt */
 extern u32 *stack;       /* stack */