/* file: computer.h */



/* Round V to next greatest B boundary */

#define ROUND(V, B) (((int) V + (B-1)) & ~(B-1))


/* Sign-extend a short to a long */

#define SIGN_EX(X)	((X) & 0x8000 ? (X) | 0xffff0000 : (X))


#define K 1024

/* Type of a memory address. */

typedef unsigned long mem_addr;

/* Type of an instuction */
typedef unsigned long instruction;

#define BYTES_PER_WORD 4	/* On the MIPS processor */

/* Type for a register */
typedef long reg_word;

/* Register names */
#define REG_SP 29


/* Macros for disassembling 32-bitinstructions */
#define OPCODE(INST)	(INST & 0xfc000000)

#define RS(INST)	(INST & 0x03e00000)
#define FS(INST)	(INST & 0x03e00000)
#define BASE(INST)	(INST & 0x03e00000)

#define RT(INST)	(INST & 0x001f0000)
#define FT(INST)	(INST & 0x001f0000)

#define RD(INST)	(INST & 0x0000f800)
#define FD(INST)	(INST & 0x0000f800)

#define SHAMT(INST)	(INST & 0x000007c0)
#define FORMAT(INST)	(INST & 0x000007c0)

#define FUNCT(INST)     (INST & 0x0000003f)

#define IMM(INST)	(INST & 0x0000ffff)
#define IOFFSET(INST)	(INST & 0x0000ffff)
#define COND(INST)	(INST & 0x0000ffff)

#define TARGET(INST)	(INST & 0x03ffffff)

/* Opcodes                               */
#define R_TYPE_OP        0
#define ADDIU_OP         9
#define ANDI_OP         12
#define ORI_OP          13
#define LW_OP           35
#define SW_OP           43
#define LUI_OP          15
#define BEQ_OP           4
#define BNE_OP           5
#define SLTI_OP         10
#define SLTIU_OP        11
#define J_OP             2
#define JAL_OP           3


/* Funct field values                    */
#define ADDU_FUNCT      33
#define SUBU_FUNCT      35
#define AND_FUNCT       36
#define OR_FUNCT        37
#define SLL_FUNCT        0
#define SRL_FUNCT        2
#define SLT_FUNCT       42
#define SLTU_FUNCT      43
#define JR_FUNCT         8

#define SYSCALL_FUNCT   12


/* Bottom of the text portion of memory: */
/* where the program is stored.          */
#define TEXT_BOTTOM (0x00400000)
#define DATA_BOTTOM (0x00401000)
#define MEM_TOP  (0x00404000)


/* The computer is declared here */
struct SimulatedComputer {

  /* Program Counter */
  reg_word PC;
  /* General purpose registers: */
  reg_word R[32];
  /* Memory */
  reg_word Mem[(MEM_TOP - TEXT_BOTTOM)/BYTES_PER_WORD ];

};