got file loading working properly

doc/internal/mem.txt

@@ -1,7 +1,6 @@
-0x0001.0000 - 0x0001.ffff: unused
-0x0002.0000 - 0x0002.7fff: fat
-0x0002.8000 - 0x0002.bfff: unused
-0x0002.c000 - 0x0002.ffff: file buffers
-0x0003.0000 - 0x0003.7fff: kernel
-0x0003.8000 - 0x0003.ffff: stack
-0x0004.0000 - 0x000f.ffff: unused
+0x0001.0000 - 0x0001.ffff (64k): unused
+0x0002.0000 - 0x0002.7fff (32k): fat
+0x0002.8000 - 0x0002.bfff (16k): unused
+0x0002.c000 - 0x0002.ffff (16k): 32 file buffers
+0x0003.0000 - 0x0003.7fff (32k): kernel
+0x0003.8000 - 0x0003.ffff (32k): kernel stack

fs/bleh.txt

@@ -0,0 +1 @@
+blah

makefile

@@ -1,4 +1,4 @@
-disk: kernel boot
+disk: kernel boot fs-
 	mkdir -p obj out
 	/sbin/mkfs.fat -C -f 1 -F 16 -n "PORTLAND OS" -R 17 -s 1 -S 512 obj/shadow.img 8192
 	echo -n -e '\xeb\x3c' > obj/jmp.bin
@@ -6,13 +6,17 @@ disk: kernel boot
 	dd if=out/boot.bin of=obj/shadow.img obs=1 seek=62 conv=notrunc
 	dd if=out/kernel.bin of=obj/shadow.img seek=1 conv=notrunc
 	mv obj/shadow.img out/disk.img
+	mcopy -i out/disk.img -s out/fs/bleh.txt ::/
 
 vdi-file: disk
 	VBoxManage convertfromraw out/disk.img out/disk.vdi --uuid a61929ed-3bf2-45ff-b98a-44f87c616dba
 
-debug: vdi-file
+debug: disk
 	gdb -x qemu-debug.gdb
 
+fs-:
+	cp -r fs out/fs
+
 kgccargs = -m32 -ffreestanding -fno-asynchronous-unwind-tables
 kernel:
 	mkdir -p obj/kernel out

qemu-debug.gdb

@@ -2,5 +2,6 @@ target remote | qemu-system-i386 -S -gdb stdio out/disk.img
 add-symbol-file obj/kernel.elf
 set disassembly-flavor intel
 layout reg
-break *0x30000
+break main
+break panic
 cont

src/kernel/fat.c

@@ -7,8 +7,28 @@ void load_fat() {
   read_sectors(FAT_INFO->reserved_sectors, FAT_INFO->sectors_per_fat, FAT);
 }
 
-bool check_fat_name(uint8_t *fname, uint8_t *sname) {
-  panic("Not implemented (check_fat_name)");
+bool to_fat_name(uint8_t *sname, uint8_t *fname) {
+  uint8_t *sp = sname, *fp = fname;
+  while (*sp != '.') {
+    if (!*sp) {
+      while (fp != fname + 11)
+        *(fp++) = ' ';
+      return false;
+    }
+    if (sp == sname + 8)
+      return true;
+    *(fp++) = *(sp++);
+  }
+  while (fp != fname + 8)
+    *(fp++) = ' ';
+  while (*++sp) {
+    if (fp == fname + 11)
+      return true;
+    *(fp++) = *sp;
+  }
+  while (fp != fname + 11)
+    *(fp++) = ' ';
+  return false;
 }
 
 bool check_fat_names(uint8_t *lname, uint8_t *rname) {
@@ -27,27 +47,35 @@ void load_root() {
 }
 
 struct directory_entry *load_subentry(uint8_t *name) {
+  uint8_t fname[11];
+  if (to_fat_name(name, fname))
+    return 0;
   struct directory_entry *ptr = buffer;
   uint16_t dir_current = dir_start;
-  do
-    if (((ptr == buffer + 16) && !read_sectors(buffer_from = dir_current++, 1, ptr = buffer)) || !ptr->name[0])
-      return 0;
-  while (!check_fat_name(ptr->name, name));
+  read_sectors(buffer_from = dir_current, 1, buffer);
+  while (*(uint8_t *)ptr) {
+    if (check_fat_names(ptr->name, fname))
       return ptr;
+    if (++ptr == buffer + 16) {
+      read_sectors(buffer_from = ++dir_current, 1, buffer);
+      ptr = buffer;
+    }
+  };
+  return 0;
 }
 
 bool load_subdir(uint8_t *name) {
   struct directory_entry *e = load_subentry(name);
   if (!e)
     return true;
-  dir_start = e->first_cluster;
+  dir_start = CTOS(e->first_cluster);
   return false;
 }
 
 struct directory_entry *load_entry(uint8_t *path) {
   load_root();
-  for (uint8_t *ptr = path; ptr; ++ptr)
-    if (*ptr = '/') {
+  for (uint8_t *ptr = path; *ptr; ++ptr)
+    if (*ptr == '/') {
       *ptr = 0;
       if (load_subdir(path))
         return 0;

src/kernel/main.c

@@ -54,5 +54,19 @@ void main() {
     u32_dec(e.length, nbuf);
     vga_printsz(nbuf);
   }
+  fs_close(root);
+  if (root = fs_open("BLEH.TXT")) {
+    vga_printsz("\n\nContents of BLEH.TXT:");
+    uint8_t l;
+    uint8_t line[82];
+    line[0] = '\n';
+    line[1] = ' ';
+    line[2] = ' ';
+    while (l = fs_read(root, 78, line + 3)) {
+      line[l + 3] = 0;
+      vga_printsz(line);
+    }
+    fs_close(root);
+  }
   halt();
 }