Refactored the C files out into libraries, started work on the BASIC repl (it can sorta do math!)

.gitignore

@@ -0,0 +1 @@
+src/*o

src/basic.c

@@ -0,0 +1,153 @@
+#include "basic.h"
+#include "screen.h"
+#include "conio.h"
+#include "string.h"
+#include "stdlib.h"
+
+struct basic_math_expr math_expressions[8];
+int basic_errno;
+
+char _tokenizer_value[BASIC_TOKENIZER_MAX_LENGTH];
+char *_tokenizer_prev;
+char *_tokenizer_prev_next;
+
+void _tokenizer_init(void)
+{
+  _tokenizer_prev = NULL;
+  _tokenizer_prev_next = NULL;
+}
+
+char *_tokenize(char *ptr, char token)
+{
+  char *orig = NULL;
+  int len = 0;
+
+  if ( ptr == NULL ) {
+    return NULL;
+  }
+  if ( _tokenizer_prev == ptr ) {
+    ptr = _tokenizer_prev_next;
+  }
+  orig = ptr;
+
+  memset(&_tokenizer_value, 0x00, BASIC_TOKENIZER_MAX_LENGTH);
+  while ( *ptr != token ) {
+    if ( *ptr == '\0' ) {
+      ptr -= sizeof(char);
+      break;
+    }
+    ptr += sizeof(char);
+    len += 1;
+  }
+  if ( len > BASIC_TOKENIZER_MAX_LENGTH ) {
+    basic_errno = BASIC_ERR_SYNTAX_TOKEN_LENGTH;
+    return NULL;
+  } else if ( len == 0 ) {
+    return NULL;
+  }
+  memcpy((void *)&_tokenizer_value, (void *)orig, len); 
+  _tokenizer_prev_next = (ptr + 1);
+  return &_tokenizer_value;
+}
+
+struct basic_math_expr *basic_parse_expr(char *expbuf)
+{
+  struct basic_math_expr *ret = &math_expressions[0];
+  char flags = 0;
+  char *subptr = 0;
+
+  _tokenizer_init();
+  memset(ret, 0x0, sizeof(struct basic_math_expr));
+
+  while ( *expbuf != '\0' ) {
+    if ( *expbuf == ' ' ) {
+      expbuf += sizeof(char);
+      continue;
+    } else if ( isdigit(*expbuf) == 1 ) {
+      if ( (ret->type == 0) && (flags & BASIC_FOUND_LVAL) == BASIC_FOUND_LVAL ) {
+	basic_errno = BASIC_ERR_SYNTAX_MULTIPLE_LVALUES;
+	return NULL;
+      } else if ( ret->type == 0x0 ) {
+	ret->lval = atoi(_tokenize(expbuf, ' '));
+	flags = (flags + BASIC_FOUND_LVAL);
+      } else if ( ret->type != 0x0 && ((flags & BASIC_FOUND_RVAL) == BASIC_FOUND_RVAL)) {
+	basic_errno = BASIC_ERR_SYNTAX_MULTIPLE_RVALUES;
+	return NULL;
+      } else if ( ret->type != 0x0 ) {
+	ret->rval = atoi(_tokenize(expbuf, ' '));
+      }
+    } else if ( ret->type == 0x0 ) {
+      if ( *expbuf == '+' ) {
+	ret->type = BASIC_MATH_ADD;
+      } else if ( *expbuf == '*' ) {
+	ret->type = BASIC_MATH_MUL;
+      } else if ( *expbuf == '-' ) {
+	ret->type = BASIC_MATH_SUB;
+      } else if ( *expbuf == '/' ) {
+	ret->type = BASIC_MATH_DIV;
+      } else if ( *expbuf == '%' ) {
+	ret->type = BASIC_MATH_MOD;
+      } else {
+	basic_errno = BASIC_ERR_SYNTAX_GENERAL;
+	return NULL;
+      }
+    } else { 
+      basic_errno = BASIC_ERR_SYNTAX_GENERAL;
+      return NULL;
+    }
+    expbuf += sizeof(char);
+  }
+  return ret;
+}
+
+void basic_run(void)
+{
+  char keybuff[512];
+  char outbuff[128];
+  char decimal;
+
+  struct basic_math_expr *expr;
+
+  blankScreen();
+  setCursorPosition(0, 0);
+  _cputs("Piquant Basic v0.1\n\n");
+
+  while ( 1 ) {
+    _cputs("> ");
+    memset((void *)&keybuff, 0x00, 512);
+    memset((void *)&outbuff, 0x00, 128);
+    if ( _cgets((char *)&keybuff) != NULL ) {
+      _cputs("\n");
+      _cputs("Analyzing ");
+      _cputs((char *)&keybuff);
+      _cputs("\n");
+
+      expr = basic_parse_expr((char *)&keybuff);
+      if ( expr == NULL ) {
+	_cputs("Syntax Error: ");
+	decimal = dtoa(basic_errno);
+	_cputs(&decimal);
+	_cputs("\n");
+	continue;
+      }
+
+      decimal = dtoa(expr->type);
+      memcpy(&outbuff, "Expression type: \0", strlen("Expression type: \0"));
+      strncat(&outbuff, &decimal, 1);
+      _cputs(&outbuff);
+      _cputs("\n");
+
+      decimal = dtoa(expr->lval);
+      memcpy(&outbuff, "Expression lval: \0", strlen("Expression lval: \0"));
+      strncat(&outbuff, &decimal, 1);
+      _cputs(&outbuff);
+      _cputs("\n");
+
+      decimal = dtoa(expr->rval);
+      memcpy(&outbuff, "Expression rval: \0", strlen("Expression rval: \0"));
+      strncat(&outbuff, &decimal, 1);
+      _cputs(&outbuff);
+      _cputs("\n");
+    }
+  }
+}

src/basic.h

@@ -0,0 +1,39 @@
+#ifndef _BASIC_H_
+#define _BASIC_H_
+
+#define BASIC_MATH_ADD 1
+#define BASIC_MATH_SUB 2
+#define BASIC_MATH_MUL 3
+#define BASIC_MATH_DIV 4
+#define BASIC_MATH_MOD 5
+
+#define BASIC_LVAL_EXPR  0
+#define BASIC_LVAL_VAR   1
+#define BASIC_RVAL_EXPR  2
+#define BASIC_RVAL_VAR   3
+#define BASIC_RVAL_CONST 4
+
+#define BASIC_FOUND_LVAL 0x0001
+#define BASIC_FOUND_RVAL 0x0002
+
+#define BASIC_ERR_SYNTAX_MULTIPLE_LVALUES 1
+#define BASIC_ERR_SYNTAX_TOKEN_LENGTH 2
+#define BASIC_ERR_SYNTAX_GENERAL 3
+#define BASIC_ERR_SYNTAX_MULTIPLE_RVALUES 4
+
+#define BASIC_TOKENIZER_MAX_LENGTH 512
+
+struct basic_math_expr {
+  char type;
+  char lval_type;
+  char rval_type;
+  char pad;
+  void *lval;
+  void *rval;
+};
+
+extern int basic_errno;
+
+void run_basic(void);
+
+#endif /* _BASIC_H_ */

src/conio.c

@@ -0,0 +1,90 @@
+#include "types.h"
+#include "conio.h"
+#include "screen.h"
+
+void _putch(char c)
+{
+#asm
+  push bx;
+  push ax;
+  mov bx, sp;
+  mov al, [bx+6];
+  mov ah, #0x0e;
+  mov bh, #0x00;
+  mov bl, #0x07;
+  int 0x10;
+  pop ax;
+  pop bx;
+#endasm
+    return;
+}
+
+void _cputs(char *ptr) 
+{
+  if ( ptr == NULL ) {
+    return;
+  }
+  while ((char)*ptr != 0x0) { 
+    _putch((char)*ptr);
+    if (*ptr == '\n') {
+      _cursor_y += 1;
+      _cursor_x = 0;
+      setCursorPosition(_cursor_x, _cursor_y);
+    } else {
+      advanceCursor();
+    }
+    ptr += 1;
+  }
+  return;
+}
+
+char _getkey(char *dest)
+{
+  char echo;
+  char scancode;
+#asm
+  push ax;
+  mov ah, #0x10;
+  int 0x16;
+  mov [bp-6], ah;
+  mov [bp-5], al;
+  pop ax;
+#endasm
+  *dest = echo;
+  return scancode;
+}
+
+char *_cgets(char *d)
+{
+  char *orig = d;
+  char scancode;
+  char printable;
+
+  if ( d == NULL ) {
+    return NULL;
+  }
+
+  scancode = _getkey(&printable);
+
+  while ( scancode != NULL ) {
+    if ( scancode == 0x0e ) {
+      if ( d > orig ) {
+	backupCursor();
+	setCursorPosition(_cursor_x, _cursor_y);
+	d -= 1;
+	_putch(0x0);
+      }
+    } else if ( scancode == 0x1c ) {
+      break;
+    } else {
+      *(d++) = printable;
+      _putch(printable);
+      advanceCursor();
+    } 
+    scancode = _getkey(&printable);
+  }
+  
+ __cgets_finish_loop:
+  *d = NULL;
+  return orig;
+}

src/conio.h

@@ -0,0 +1,8 @@
+#ifndef _CONIO_H_
+#define _CONIO_H_
+
+void _putch(char _c);
+char *_cgets(void);
+char _getkey(char *dest);
+
+#endif /* _CONIO_H_ */

src/kernel.c

@@ -1,238 +1,8 @@
-char _cursor_x = 0;
-char _cursor_y = 0;
-
-#define NULL 0x0
-typedef int size_t;
-
-void setCursorPosition(char x, char y)
-{
-#asm
-  push bx;
-  mov bx, sp;
-  mov dl, [bx+4];
-  mov dh, [bx+6];
-  pop bx;
-  push ax;
-  push bx;
-  mov ah, #0x02;
-  mov bx, #0x0;
-  int 0x10;
-  pop bx;
-  pop ax;
-#endasm
-  return;
-}
-
-void backupCursor()
-{
-  
-  if ( _cursor_x == 0 && _cursor_y > 0 ) {
-    _cursor_x = 80;
-    _cursor_y -= 1;
-  } else if ( _cursor_x > 0 ) {
-    _cursor_x -= 1;
-  }
-  setCursorPosition(_cursor_x, _cursor_y);
-}
-
-void advanceCursor()
-{
-  _cursor_x += 1;
-  if ( _cursor_x > 79 ) {
-    _cursor_x = 0;
-    _cursor_y += 1;
-  }
-  setCursorPosition(_cursor_x, _cursor_y);
-}
-
-void putc(char c)
-{
-#asm
-  push bx;
-  push ax;
-  mov bx, sp;
-  mov al, [bx+6];
-  mov ah, #0x0e;
-  mov bh, #0x00;
-  mov bl, #0x07;
-  int 0x10;
-  pop ax;
-  pop bx;
-#endasm
-    return;
-}
-
-int strlen(char *ptr)
-{
-  char *ptr2 = ptr;
-  if ( ptr == NULL ) {
-    return 0;
-  }
-
-  while (*ptr2 != 0x0 ) {
-    ptr2 += 1;
-  }
-
-  return ptr2 - ptr;
-}
-
-void puts(char *ptr, char x, char y) 
-{
-  if ( ptr == NULL ) {
-    return;
-  }
-  while ((char)*ptr != 0x0) { 
-    putc((char)*ptr);
-    if (*ptr == '\n') {
-      _cursor_y += 1;
-      _cursor_x = 0;
-      setCursorPosition(_cursor_x, _cursor_y);
-    } else {
-      advanceCursor();
-    }
-    ptr += 1;
-  }
-  return;
-}
-
-char getkey(char *dest)
-{
-  char echo;
-  char scancode;
-#asm
-  push ax;
-  mov ah, 0x10;
-  int 0x16;
-  mov [bp-6], ah;
-  mov [bp-5], al;
-  pop ax;
-#endasm
-  *dest = echo;
-  return scancode;
-}
-
-char *gets(char *d)
-{
-  char *orig = d;
-  char scancode;
-  char printable;
-
-  if ( d == NULL ) {
-    return NULL;
-  }
-
-  scancode = getkey(&printable);
-
-  while ( scancode != NULL ) {
-    if ( scancode == 0x0e ) {
-      if ( d > orig ) {
-	backupCursor();
-	setCursorPosition(_cursor_x, _cursor_y);
-	d -= 1;
-	putc(0x0);
-      }
-    } else if ( scancode == 0x1c ) {
-      break;
-    } else {
-      *(d++) = printable;
-      putc(printable);
-      advanceCursor();
-    } 
-    scancode = getkey(&printable);
-  }
-  
- _gets_finish_loop:
-  *d = NULL;
-  return orig;
-}
-
-void memset(void *s, int c, size_t n)
-{
-  int *d = (int *)s;
-  if ( s == NULL ) {
-    return;
-  }
-  while ( ((int)d - (int)s) <= n ) {
-    *d = c;
-    d += sizeof(int);
-  }
-}
-
-signed int strcmp(char *s1, char *s2)
-{
-  int d = 0;
-  int s1len = 0;
-
-  if ( s1 == NULL || s2 == NULL ) {
-    return 1;
-  }
-
-  s1len = strlen(s1);
-  if ( s1len != strlen(s2) ) {
-    return 1;
-  }
-
-  while ( *s1 != '\0' ) {
-    if ( *s1 != *s2 ) {
-      return 1;
-    }
-    s1 += sizeof(char);
-    s2 += sizeof(char);
-  }
-
-  return 0;
-}
-
-void repl(void)
-{
-  char keybuff[512];
-
-  while ( 1 ) {
-    puts("> ");
-    memset((void *)&keybuff, 0x00, 512);
-    if ( gets((char *)&keybuff) != NULL ) {
-      puts("\n");
-      if ( strcmp(&keybuff, "quit") == 0 ) {
-	puts("You asked for it\n");
-	#asm
-	hlt;
-	#endasm
-
-      } else if ( strcmp(&keybuff, "reset") == 0 ) {
-	puts("Resetting PC ... ");
-	#asm
-	jmp 0xf000:0xfff0;
-	#endasm
-
-      } else if ( strcmp(&keybuff, "help") == 0 ) {
-	puts("help : Show this help message\n");
-	puts("quit : Halt the computer\n");
-	puts("reset : Reset the PC\n");
-	puts("\n");
-      } else {
-	puts("Wat?\n");
-      }
-    }
-  }
-}
-
-void blankScreen(void)
-{
-  char i = 0;
-  char j = 0;
-  for ( i = 0 ; i < 26 ; i++ ) {
-    for ( j = 0; j < 81 ; j++ ) {
-      setCursorPosition(j, i);
-      putc(' ');
-    }
-  }
-}
+#include "screen.h"
+#include "string.h"
+#include "conio.h"
 
 void main(void)
 {
-  blankScreen();
-  setCursorPosition(0, 0);
-  puts("Piquant Kernel v0.1\n");
-  puts("\n");
-  repl();
+  basic_run();
 }

src/screen.c

@@ -0,0 +1,58 @@
+#include "types.h"
+#include "screen.h"
+
+char _cursor_x = 0;
+char _cursor_y = 0;
+
+void blankScreen(void)
+{
+  char i = 0;
+  char j = 0;
+  for ( i = 0 ; i < 26 ; i++ ) {
+    for ( j = 0; j < 81 ; j++ ) {
+      setCursorPosition(j, i);
+      _putch(0x0);
+    }
+  }
+}
+
+void setCursorPosition(char x, char y)
+{
+#asm
+  push bx;
+  mov bx, sp;
+  mov dl, [bx+4];
+  mov dh, [bx+6];
+  pop bx;
+  push ax;
+  push bx;
+  mov ah, #0x02;
+  mov bx, #0x0;
+  int 0x10;
+  pop bx;
+  pop ax;
+#endasm
+  return;
+}
+
+void backupCursor()
+{
+  
+  if ( _cursor_x == 0 && _cursor_y > 0 ) {
+    _cursor_x = 80;
+    _cursor_y -= 1;
+  } else if ( _cursor_x > 0 ) {
+    _cursor_x -= 1;
+  }
+  setCursorPosition(_cursor_x, _cursor_y);
+}
+
+void advanceCursor()
+{
+  _cursor_x += 1;
+  if ( _cursor_x > 79 ) {
+    _cursor_x = 0;
+    _cursor_y += 1;
+  }
+  setCursorPosition(_cursor_x, _cursor_y);
+}

src/screen.h

@@ -0,0 +1,12 @@
+#ifndef _SCREEN_H_
+#define _SCREEN_H_
+
+extern char _cursor_x;
+extern char _cursor_y;
+
+void setCursorPosition(char x, char y);
+void backupCursor();
+void advanceCursor();
+void blankScreen();
+
+#endif /* _SCREEN_H_ */

src/stdlib.c

@@ -0,0 +1,81 @@
+#include "types.h"
+#include "stdlib.h"
+
+char dtoa(int d)
+{
+  switch (d) {
+  case 0: return '0'; break;
+  case 1: return '1'; break;
+  case 2: return '2'; break;
+  case 3: return '3'; break;
+  case 4: return '4'; break;
+  case 5: return '5'; break;
+  case 6: return '6'; break;
+  case 7: return '7'; break;
+  case 8: return '8'; break;
+  case 9: return '9'; break;
+  }
+}
+
+int atoi(char *nptr)
+{
+  int value = 0;
+  char *ptr = nptr;
+  int multiplier = 1;
+
+  if ( nptr == NULL ) {
+    return 0;
+  }
+  while ( isdigit(*ptr) == 1 ) {
+    ptr += 1;
+  }
+  ptr -= 1;
+  while ( ptr >= nptr) {
+    value += (((int)(*ptr--) - 0x30) * multiplier);
+    multiplier *= 10;
+  }
+  return value;
+}
+
+int isdigit(int c)
+{
+  if (c >= 0x30 && c <= 0x39) {
+    return 1;
+  }
+  return 0;
+}
+
+int isupper(int c)
+{
+  if (c >= 0x41 && c <= 0x5A) {
+    return 1;
+  }
+  return 0;
+}
+
+int islower(int c)
+{
+  if (c >= 0x61 && c <= 0x7A) {
+    return 1;
+  }
+  return 0;
+}
+
+int isalnum(int c)
+{
+  if ( isupper(c) || islower(c) || isdigit(c) ) {
+    return 1;
+  }
+  return 0;    
+}
+
+int isxdigit(int c)
+{
+  if ( isdigit(c) || 
+       (c >= 0x41 && c <= 0x46) ||
+       (c >= 0x61 && c <= 0x66)
+       ) {
+    return 1;
+  }
+  return 0;
+}

src/stdlib.h

@@ -0,0 +1,12 @@
+#ifndef _STDLIB_H_
+#define _STDLIB_H_
+
+char dtoa(int d);
+int atoi(char *nptr);
+int isdigit(int c);
+int isupper(int c);
+int islower(int c);
+int isalnum(int c);
+int isxdigit(int c);
+
+#endif /* _STDLIB_H_ */

src/string.c

@@ -0,0 +1,83 @@
+#include "types.h"
+#include "string.h"
+
+size_t strlen(char *ptr)
+{
+  char *ptr2 = ptr;
+  if ( ptr == NULL ) {
+    return 0;
+  }
+
+  while (*ptr2 != 0x0 ) {
+    ptr2 += 1;
+  }
+
+  return ptr2 - ptr;
+}
+
+void *memset(void *s, int c, size_t n)
+{
+  int *d = (int *)s;
+  if ( s == NULL ) {
+    return NULL;
+  }
+  while ( ((int)d - (int)s) <= n ) {
+    *d = c;
+    d += sizeof(int);
+  }
+  return s;
+}
+
+void *memcpy(void *dest, void *src, size_t n)
+{
+  int i = 0;
+  char *d = dest;
+  char *s = src;
+
+  if ( d == NULL || s == NULL ) {
+    return NULL;
+  }
+  for ( i = 0 ; i < n ; i++ ) {
+    *d++ = *s++;
+  }
+  *d = '\0';
+  return dest;
+}
+
+int strncat(char *dest, char *src, size_t n)
+{
+  int c = 0;
+  if ( dest == NULL || src == NULL ) {
+    return 0;
+  }
+  dest = (dest + strlen(dest));
+  while ( c++ < n ) {
+    *dest++ = *src++;
+  }
+  return c;
+}
+
+int strcmp(char *s1, char *s2)
+{
+  int d = 0;
+  int s1len = 0;
+
+  if ( s1 == NULL || s2 == NULL ) {
+    return 1;
+  }
+
+  s1len = strlen(s1);
+  if ( s1len != strlen(s2) ) {
+    return 1;
+  }
+
+  while ( *s1 != '\0' ) {
+    if ( *s1 != *s2 ) {
+      return 1;
+    }
+    s1 += sizeof(char);
+    s2 += sizeof(char);
+  }
+
+  return 0;
+}

src/string.h

@@ -0,0 +1,12 @@
+#ifndef _STRING_H_
+#define _STRING_H_
+
+#include "types.h"
+
+size_t strlen(char *ptr);
+int strncat(char *dest, char *src, size_t n);
+void *memset(void *s, int c, size_t n);
+void *memcpy(void *dest, void *src, size_t n);
+int strcmp(const char *s1, const char *s2);
+
+#endif /* _STRING_H_ */

src/types.h

@@ -0,0 +1,7 @@
+#ifndef _TYPES_H_
+#define _TYPES_H_
+
+#define NULL 0x0
+typedef int size_t;
+
+#endif /* _TYPES_H_ */