.text

/* Switch from current_thread to next_thread. Make next_thread
 * the current_thread, and set next_thread to 0.
 * Use eax as a temporary register, which should be caller saved.
 */

/* Some useful notes:
 *  - current_thread and next_thread are global variables, and there are
 *    no arguments to the thread_switch() function.
 *  - to load from / store to an address in assembler, use just the symbol:
 *      mov   foo,%eax     // load contents of address 'foo' into eax
 *  - why do you need a temporary register? 
 *  - why is it nice that 'sp' is the first field (offset 0) in struct thread?
 *  - thread_create assumes that thread_switch stores 32 bytes (8 words) 
 *    of registers on the stack. Funny, pushal stores 8 registers...
 */

	.globl thread_switch
thread_switch:
	/* YOUR CODE HERE */
	ret				/* pop return address from stack */