filesystem structure intro and docs

- new type pid_t and program management mechanism to make it
  easier to switch to a multitasking kernel
- new memory related functions in memory.h to move, copy and
  manage pages
- fix typos

5 files changed, 93 insertions, 12 deletions

diff --git a/sw/z80/kernel/include/filesystem.h b/sw/z80/kernel/include/filesystem.h
new file mode 100644
index 0000000..6505d5e
--- /dev/null
+++ b/sw/z80/kernel/include/filesystem.h
@@ -0,0 +1,77 @@
+#ifndef __FILESYSTEM_H__
+#define __FILESYSTEM_H__
+
+#include "types.h"
+
+#define FS_OFFSET 0x1000
+
+#define FS_BLOCK_SIZE   512
+#define FS_BLOCKS_N     12
+/* #define FS_IBLOCKS_N     1 */
+
+#define INODE_TYPE_FILE 0
+#define INODE_TYPE_DIR  1
+#define INODE_TYPE_LINK 2
+
+typedef struct time_s
+{
+    uint16_t time;
+    uint16_t date;
+} time_t;
+
+
+/* on-disk structures */
+struct fs_superblock
+{
+    uint8_t     magic;
+    uint16_t    blk_size;   /* default is 512 bytes */
+    uint16_t    imap_size;  /* size of the inode bitmap in blocks */
+    uint16_t    dmap_size;  /* size of the data blocks map in blocks */
+};
+
+
+struct fs_blk
+{
+    uint    size;
+};
+
+typedef struct fs_inode
+{
+    uint        i_used :1; // inode is free
+    uint        i_mode :3; // inode mode (rwx)
+
+    uint8_t     i_uid;     // user (owner) id
+    uint16_t    i_number;  // identifier
+
+    uint16_t    i_blocks;  // number of blocks
+
+    struct fs_blk   i_block[FS_BLOCKS_N];   // direct blocks
+/*    struct fs_blk   i_iblock[FS_IBLOCKS_N]; // indirect blocks */
+    
+    inode_t     *parent;
+} inode_t;
+
+/* inode table structures */
+struct fs_inode_entry
+{
+    uint16_t    i_number;
+    uint8_t     str_len;
+    char        name[24];
+};
+
+/* filesystem struct for the operating system */
+struct filesystem
+{
+    size_t size;
+    size_t fsize;
+    inode_t *mntpt;
+};
+
+void fs_parse_superblock(struct filesystem *fs);
+
+void fs_write_imap();
+void fs_write_dmap();
+
+/* void fs_ */
+
+#endif // __FILESYSTEM_H__
diff --git a/sw/z80/kernel/include/memory.h b/sw/z80/kernel/include/memory.h
index 5bca5a5..e4352b5 100644
--- a/sw/z80/kernel/include/memory.h
+++ b/sw/z80/kernel/include/memory.h
@@ -34,7 +34,7 @@
 struct page
 {
 	uint used :1;
-	uint8_t pid;     // process owner of the page
+	pid_t pid;     // process owner of the page
     uint16_t addr;   // physical address
 };
 
diff --git a/sw/z80/kernel/include/process.h b/sw/z80/kernel/include/process.h
index ffd39e7..d7aa7fd 100644
--- a/sw/z80/kernel/include/process.h
+++ b/sw/z80/kernel/include/process.h
@@ -2,6 +2,7 @@
 #define __PROCESS_H__
 
 #include "types.h"
+#include "memory.h"
 
  /* maximum number of processes (i.e. pages in ram)
   * since each program can use only one page in ram
@@ -10,17 +11,17 @@
 
 struct executable
 {
-	void *text;
-	size_t text_size;
-	void *bss;
-	size_t bss_size;
-}
+    void *text;
+    size_t text_size;
+    void *bss;
+    size_t bss_size;
+};
 
 struct process
 {
-    uint blocked :1;	// process is waiting for hardware or locked
-    uint running :1;	// pid is used
-    uint pages[4];		// pages used by the process
+    uint blocked :1;    // process is waiting for hardware or locked
+    uint running :1;    // pid is used
+    struct page pages[4];      // pages used by the process
     // TODO: implement quick callback?
 };
 
@@ -29,8 +30,9 @@ struct process
  * limitation but for our purposes is more than enough
  */
 extern struct process proc_table[255];
+extern struct process *current_proc;
 
-static pid_t newpid(void);
+pid_t newpid(void);
 
 int fork(void);
 int exec(char *path, char *args);
diff --git a/sw/z80/kernel/include/syscall.h b/sw/z80/kernel/include/syscall.h
index 9641f25..29941c9 100644
--- a/sw/z80/kernel/include/syscall.h
+++ b/sw/z80/kernel/include/syscall.h
@@ -1,5 +1,5 @@
-#ifndef SYS_CALL
-#define SYS_CALL
+#ifndef __SYS_CALL_H__
+#define __SYS_CALL_H__
 
 /*
 *   Enable / disable virtual address traslation
diff --git a/sw/z80/kernel/include/types.h b/sw/z80/kernel/include/types.h
index 44df3eb..7c1424a 100644
--- a/sw/z80/kernel/include/types.h
+++ b/sw/z80/kernel/include/types.h
@@ -1,6 +1,8 @@
 #ifndef __TYPES_H__
 #define __TYPES_H__
 
+/* only types from primitive types are defined in this file */ 
+
 #define register_t  volatile unsigned char
 
 #define uint 		unsigned int