Properly read the file names from the directory in shell

shell.asm

@@ -395,30 +395,25 @@ click:
 		mov ax, bx
 		sub ax, [si + window.y]
 		jz .end
+		dec ax
 
-		; Find the start of the line user clicked on
-		mov bx, [si + window.width]
-		shl bx, 1
-		mul bx
+		push ds
 
-		mov si, [si + window.data]
+		mov bp, PONYDOS_SEG
+		mov ds, bp
+
+		mov bp, FS_DIRENT_SIZE
+		mul bp
+		mov si, GLOBAL_DIRENTS
 		add si, ax
-
-		; Zero out launch_filename
-		mov di, launch_filename
-		mov cx, FS_DIRENT_NAME_SIZE
-		xor al, al
-		rep stosb
+		add si, 2 ; File name begins two bytes into the start of the dirent
 
 		; Copy file name to launch_filename
 		mov di, launch_filename
-		.copy_filename_loop:
-			lodsw
-			test al, al
-			jz .copy_filename_loop_end
-			stosb
-			jmp .copy_filename_loop
-		.copy_filename_loop_end:
+		mov cx, FS_DIRENT_NAME_SIZE
+		rep movsb
+
+		pop ds
 
 		call launch