decoder.h

一个用在mips体系结构中的操作系统

/*
 * Copyright (C) 1996-1998 by the Board of Trustees
 *    of Leland Stanford Junior University.
 * 
 * This file is part of the SimOS distribution. 
 * See LICENSE file for terms of the license. 
 *
 */

#ifndef DECODER_H
#define DECODER_H

/* Opcode information not in that file */
#define bcfl_op 0x02
#define bctl_op 0x03
/* Simos hacked opcodes */
#define SIMOS_HACKED_SYSCALL 0x8c020003 	  /* lw v0, 3($0) */
#define SIMOS_HACKED_TNS 0x8c880001       /* lw t0, 1(a0) */
/* This is a reserved opcode in R10000 */
#define mendel_tns (swc2_op+1)

/* maximum number of instructions in one group */
extern int maxInGroup;

typedef unsigned Instruction;

/* Register allocation information */
typedef struct {
  int reg_num;
  int num_src;
  int alloc_reg;
}alloc_reg_t;
/* Absolute max number of instructions in a basic block.  Anything */
/* over 50 seems reasonable */
#define INST_GRP_LIMIT 60

typedef struct  { 
   int cpuNum;
   VA virt_pc;
   PA phys_pc;
   MA maPC;
   int GrpLen;
   PA next_phys_pc;
   MA next_maPC;
   int numDMemoryAcesses;
   int numIMemoryAcesses;
   int isKseg0;
   /* This flag tells us to not chain this block (can't chain from */
   /* kernel to user) */ 
   int is_rfe_block;
   /* This flag tells us to skip register allocation */
   int no_reg_allocate;
   /* This flag tells us if the delay slot squashes a regsiter that is */
   /* used by the control transfer instruction */

   int is_delay_slot_instr;
   int delay_slot_reg_conflict;
  alloc_reg_t* reg2alloc;
   Instruction instrs[INST_GRP_LIMIT];
   int pcAnn[INST_GRP_LIMIT];
  /* Reg allocation information structures, referenced by register number */
}InstrGrp; 

/*****************************************************************
 * This information comes from "MIPS RISC ARCHITECTURE" and is   *
 * found on page 3-1.                                            *
 *                                                               *
 * All instructions are 32 bits and aligned on a word boundary.  *
 *****************************************************************/

/* Macros to EXTRACT each instruction field. The  lowest order bit will be at position 0 */

#define MAJOR_OPCODE(_instr) ( ((unsigned)_instr >> 26 ) & 0x3f )
#define rs(_inst)     (((unsigned)_inst >> 21) & 0x1f )
#define rt(_inst)     (((unsigned)_inst >> 16) & 0x1f )
#define rd(_inst)     (((unsigned)_inst >> 11) & 0x1f )
#define SHAMT(_inst)  (((unsigned)_inst >> 6) & 0x1f )
#define fs(_inst)     (((unsigned)_inst >> 11) & 0x1f )
#define ft(_inst)     (((unsigned)_inst >> 16) & 0x1f )
#define fd(_inst)     (((unsigned)_inst >> 6) & 0x1f )
#define FUNC(_inst)   ((unsigned)_inst & 0x0000003f )
#define FORMAT(_inst)   (((uint)_inst >> 21) & 0x1f )
/* Doing it this way allows the values to be sign extended */
#define IMMED(_inst)  ( ((int)_inst << 16 ) >> 16 )
#define TARGET(_inst) ((unsigned)_inst & 0x03ffffff )
#define IS_FCMP(_inst) (((unsigned)_inst >> 3) & 0x3 )
#define IS_CP0_FUNC(_inst) (((unsigned)_inst >> 25 ) & 0x1 )
/* NOTE: this does not match the format in the MIPS book, but the kernel */
/* and debugger agree, so that's what we will use */
#define BREAK_CODE(_inst) (((unsigned)_inst >> 16 ) & 0x3ff )


extern void DecoderInit( void );
extern void DecodeInstrs( InstrGrp*,int cpuNum, VA pc, int is_delay_slot_instr );
extern int  IsCtlInstr(uint inst);
extern VA   EndOfBB(VA pc, MA mA);

/* XXX BL: added in this floating point stuff; should probably be in mips_arch.h */

#define FCMP_BITS (6<<3)
#define FC_BIT  (1<<23) /* fcr 31 condition code bit */
#define FBC_BIT (1<<16) /* compare sense of FP branch */

#define F_FMT(x) (((x)>>21)&15) /* technically 31, but 15 for mips_arch.h */

/* decode floating point compare condition field */
#define FL_BIT  (1<<2)  /* cond:2 = less than */
#define FEQ_BIT (1<<1)  /* cond:1 = equal */
#define FUN_BIT (1<<0)  /* cond:0 = unordered */

/* MIPS data formats:
 * floats:
 * sign:1 | exponent:8 | fraction:23
 *
 * doubles:
 * sign:1 | exponent:11 | fraction:52
 */

#define FFEMAX    (127)  /* max exponent for floats */
#define FDEMAX    (1023) /* max exponent for doubles */

#endif /* DECODE_H */