/* file: stm.h
 *
 * Code for the simulated toy machine (STM), 
 * a simulated architecture supporting variable-length partitions.
 *
 * FOR MOST OF OUR PROJECTS, YOU MUST NOT MODIFY THIS CODE
 * AS IT REPRESENTS OUR HARDWARE.
 *
 * Fall 2006: Operating Systems Class, Professor Yap
 *
 * THIS CODE IS modified from the original stm.c code,
 * 	with permission from Professor Ernie Davis 
 * 	The original stm.c file is split into four files:
 *
 * 	    stm.h,  stm.c
 * 	    sos.h sos.c
 *
 * 	SOS is the Simple Operating System, and is
 * 	linked to stm.o.
 *
 * VERSION CONVENTION:
 * 	Since we intend to change the hardware and software
 * 	throughout this course, we use this convention for versioning.
 *
 * 	stm1.h and stm1.c will be the name of the first modification of stm.
 * 		E.g., stm2.h and stm2.c will refer to the second, independent 
 * 		modification of stm.
 *
 * 	If you extend stm1.h and stm1.c, then it should be named stm11.h, stm11.c.  
 * 		E.g., If you extend stm213.h and stm213.c, then you should
 * 		name it stm2131.h, stm2131.c.
 *
 * 	Same principle for versioning of sos.
 * 		The slight complication is that sos must also
 * 		know which version of stm it is using.
 * 	REMARK:  Basically, we use a single digit for each version.
 * 	The "0" digit is implicit if missing.
 * 		E.g., stm.h is really stm0.h and stm00.h.
 * 		Also, sos1.h is really sos10.h.
 *
 ***************************************************/

#ifndef H_STM
#define H_STM

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/****************************************************
 * Hardware Specs
 ****************************************************/

#define RAMSIZE 262144  /* 2**18 address space */
#define NUMREGS 16

/****************************************************
 * Global variables for the simulated architecture
 ****************************************************/

extern int
      mem[RAMSIZE],  /* Core memory */
      regs[NUMREGS], /* Number of registers */
      base,          /* Base register */
      limit;         /* limit register */
      
extern char codes[16][4];   /* Op codes */
     
extern int
	debug,		/* level of debugging */
	error,		/* error flag */
	terminate;	/* termination flag */

/****************************************************
 * Convert a relative address to a physical address. Check that it
 * lies within bounds
 * Note: This is considered part of the "hardware" of the virtual machine.
 * You may not change it in any of the projects.
 ****************************************************/

extern int phys_address(int reladd);

/* Display STM instruction for level-2 debugging */

extern void show_inst(int op, int ra, int ad, int rb, int rc, int rd);

/* Decompose an STM instruction into its components 
 * Note: This is considered part of the "hardware" of the virtual machine.
 * You may not change it in any of the projects. */

extern void get_inst(int inst,
	int* pop, int* pra, int* pad, int* prb, int* prc, int* prd);

/* Execute an STM instruction. This is what does the actual work of
 * carrying out the STM code 
 * Note: This is considered part of the "hardware" of the virtual machine.
 * You may not change it in any of the projects. */

extern int exec_inst(int op, int ra, int ad, int rb, int rc, int rd);

/* Execute a trap */

extern void exec_stm();

/* stm version */

extern void STMversion();

#endif
// END of stm.h