Add close, add filesystem code to main kernel for hardware testing

sw/kernel/filesystems/fat32_c.c

@@ -20,9 +20,21 @@ size_t fat32_file_write(int8_t fd, const void* buf, size_t nbytes) {
     return -1;
 }
 
+/*
+ * file_close
+ * DESCRIPTION: close device abstracted as file
+ * INPUTS: fd -- file descriptor for file to be closed
+ * OUTPUTS: none
+ * RETURN VALUE: none
+ * SIDE EFFECTS: none
+ */
 int8_t fat32_file_close(int8_t fd) {
-    (void)fd;
-    return -1;
+    struct pcb* pcb;
+    pcb = get_pcb_ptr();
+
+    /* update pcb to remove process */
+    pcb->file_desc_array[fd].flags = !IN_USE;
+    return 0;
 }
 
 int8_t fat32_file_open(const char* filename) {
@@ -64,7 +76,6 @@ int8_t fat32_file_open(const char* filename) {
 
 size_t fat32_file_read(int8_t fd, void* buf, size_t nbytes) {
     uint16_t i;
-    uint8_t error;
     size_t offset;
     size_t leftover_length;
     size_t bytes_read = 0;

sw/kernel/kernel.c

@@ -21,6 +21,9 @@ void handle_rtc_interrupt() {
 char buf[128];
 
 int main() {
+    int8_t fd;
+    size_t nbytes, i;
+
     cputs("Kernel\n");
 
     cputs("Init Mapper\n");
@@ -49,17 +52,19 @@ int main() {
     
     fat32_init();
 
-    terminal_open(NULL);
-    terminal_write(0, "Terminal Write\n", 15);
+    /* This is what is going to be part of open */
+    fd = fat32_file_open("VERYLA~1TXT");
+    cprintf("fd: %x\n", fd);
 
-    while(1) {
-        if (terminal_read(0, buf, 128)) {
-            cprintf("Fail\n");
-            break;
+    nbytes = fat32_file_read(fd, buf, 23);
+    for (i = 0; i < nbytes; i++) {
+        cprintf("%c", buf[i]);
+    }
+
+    while ((nbytes = fat32_file_read(fd, buf, 128))){
+        for (i = 0; i < nbytes; i++) {
+            cprintf("%c", buf[i]);
         }
-        terminal_write(0, "Got: ", 5);
-        terminal_write(0, buf, strlen(buf));
-        terminal_write(0, "\n", 1);
     }
 
     return 0;

sw/kernel/process/process.h

@@ -34,11 +34,10 @@ struct pcb {
     struct file_desc file_desc_array[FILE_DESC_SIZE];
     int32_t is_vidmapped;
     uint8_t args[128];
-    uint32_t execute_return;
-    int32_t pid;
-    int32_t parent_pid;
-    uint32_t parent_esp;
-    uint32_t parent_ebp;
+    uint16_t execute_return;
+    uint16_t pid;
+    uint16_t parent_pid;
+    uint16_t parent_esp;
 };