fpu.h

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/*

  Copyright (C) 2000, 2001 Silicon Graphics, Inc.  All Rights Reserved.

  This program is free software; you can redistribute it and/or modify it
  under the terms of version 2 of the GNU General Public License as
  published by the Free Software Foundation.

  This program is distributed in the hope that it would be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

  Further, this software is distributed without any warranty that it is
  free of the rightful claim of any third person regarding infringement 
  or the like.  Any license provided herein, whether implied or 
  otherwise, applies only to this software file.  Patent licenses, if 
  any, provided herein do not apply to combinations of this program with 
  other software, or any other product whatsoever.  

  You should have received a copy of the GNU General Public License along
  with this program; if not, write the Free Software Foundation, Inc., 59
  Temple Place - Suite 330, Boston MA 02111-1307, USA.

  Contact information:  Silicon Graphics, Inc., 1600 Amphitheatre Pky,
  Mountain View, CA 94043, or:

  http://www.sgi.com

  For further information regarding this notice, see:

  http://oss.sgi.com/projects/GenInfo/NoticeExplan

*/


#ifndef __SYS_FPU_H__
#define __SYS_FPU_H__
#ifdef __cplusplus
extern "C" {
#endif


/* %Q% %I% %M% */


/*
 * fpu.h -- fpu specific defines
 */

#if defined(_LANGUAGE_C) || defined(_LANGUAGE_C_PLUS_PLUS)
/*
 * Structure and constant definisions for floating-point instructions.
 */
union fpu_instr {
        unsigned int instr;

        struct {
#ifdef _MIPSEB
                unsigned op : 6;
                unsigned base : 5;
                unsigned rt : 5;
                signed immed : 16;
#endif /* _MIPSEB */
#ifdef _MIPSEL
                signed immed : 16;
                unsigned rt : 5;
                unsigned base : 5;
                unsigned op : 6;
#endif /* _MIPSEL */
        } itype;

        struct {
#ifdef _MIPSEB
                unsigned op : 6;
                unsigned sub : 5;
                unsigned rt : 5;
                unsigned rs : 5;
                unsigned : 11;
#endif /* _MIPSEB */
#ifdef _MIPSEL
                unsigned : 11;
                unsigned rs : 5;
                unsigned rt : 5;
                unsigned sub : 5;
                unsigned op : 6;
#endif /* _MIPSEL */
        } mtype;

        struct {
#ifdef _MIPSEB
                unsigned op : 6;
                unsigned one : 1;
                unsigned fmt : 4;
                unsigned rt : 5;
                unsigned rs : 5;
                unsigned rd : 5;
                unsigned func : 6;
#endif /* _MIPSEB */
#ifdef _MIPSEL
                unsigned func : 6;
                unsigned rd : 5;
                unsigned rs : 5;
                unsigned rt : 5;
                unsigned fmt : 4;
                unsigned one : 1;
                unsigned op : 6;
#endif /* _MIPSEL */
        } rtype;

        struct {
#ifdef _MIPSEB
                unsigned op : 6;
                unsigned rr : 5;
                unsigned rt : 5;
                unsigned rs : 5;
                unsigned rd : 5;
                unsigned func : 3;
                unsigned fmt : 3;
#endif /* _MIPSEB */
#ifdef _MIPSEL
                unsigned fmt : 3;
                unsigned func : 3;
                unsigned rd : 5;
                unsigned rs : 5;
                unsigned rt : 5;
                unsigned rr : 5;
                unsigned op : 6;
#endif /* _MIPSEL */
        } r4type;
};
#endif /* _LANGUAGE_C || _LANGUAGE_C_PLUS_PLUS */

#define FMT_SINGLE      0
#define FMT_DOUBLE      1
#define FMT_EXTENDED    2
#define FMT_QUAD        3
#define FMT_WORD        4
#define FMT_LONGWORD    5
#define FMT_MAX         5

#define FUNC_ADD        0
#define FUNC_SUB        1
#define FUNC_MUL        2
#define FUNC_DIV        3

#define FUNC_SQRT       4
#define FUNC_ABS        5
#define FUNC_MOV        6
#define FUNC_NEG        7

#define FUNC_ROUNDL     0x08
#define FUNC_TRUNCL     0x09
#define FUNC_CEILL      0x0a
#define FUNC_FLOORL     0x0b

#define FUNC_ROUND      0x0c
#define FUNC_TRUNC      0x0d
#define FUNC_CEIL       0x0e
#define FUNC_FLOOR      0x0f

#define FUNC_RECIP      0x15
#define FUNC_RSQRT      0x16

#define FUNC_CVTS       0x20
#define FUNC_CVTD       0x21
#define FUNC_CVTE       0x22
#define FUNC_CVTQ       0x23
#define FUNC_CVTW       0x24
#define FUNC_CVTL       0x25

/*
 * op codes for madd, msub, nmadd, nmsub; notice that these are
 * the same as some of the other floating point op codes, however
 * they are COP1X functions.  To distinguish them in code, do
 * something like adding 64 to the op code.  Then you can do
 * a switch statement with cases like
 * case FUNC_MADD+64:
 */

#define FUNC_MADD       0x4
#define FUNC_MSUB       0x5
#define FUNC_NMADD      0x6
#define FUNC_NMSUB      0x7

/*
 * The func field of floating-point compare opcodes are FUNC_FC with
 * some combination of conditions (COND_*).
 */
#define FUNC_FC         0x30
#define COND_UN_MASK    0x1
#define COND_EQ_MASK    0x2
#define COND_LT_MASK    0x4
#define COND_IN_MASK    0x8

/*
 * The _MASK's are used to get a the specified field after it has been
 * shifted by _SHIFT and then bit patterns above can be used to test
 * the field.  These are useful in assembly code.
 */
#define FPU_BASE_SHIFT  21
#define FPU_BASE_MASK   0x1f
#define FPU_FMT_SHIFT   21
#define FPU_FMT_MASK    0xf
#define FPU_RT_SHIFT    16
#define FPU_RT_MASK     0x1f
#define FPU_RT_FPRMASK  0x1e
#define FPU_RS_SHIFT    11
#define FPU_RS_MASK     0x1f
#define FPU_RS_FPRMASK  0x1e
#define FPU_RD_SHIFT    6
#define FPU_RD_MASK     0x1f
#define FPU_RD_FPRMASK  0x1e

#if defined(_LANGUAGE_C) || defined(_LANGUAGE_C_PLUS_PLUS)
/*
 * These functions are used to get and set the floating-point control
 * registers.  They are defined in the library module fp_control.s
 */
extern unsigned int get_fpc_csr(void);
extern unsigned int set_fpc_csr(unsigned int);
extern unsigned int get_fpc_irr(void);
extern unsigned int get_fpc_eir(void);

/*
 * Structure and constant definisions for the floating-point control
 * implementation and revision register (fpc_irr).
 */
union fpc_irr {
        unsigned int fi_word;
        struct {
#ifdef _MIPSEB
                unsigned reserved : 16;
                unsigned implementation : 8;
                unsigned revision : 8;
#endif /* _MIPSEB */
#ifdef _MIPSEL
                unsigned revision : 8;
                unsigned implementation : 8;
                unsigned reserved : 16;
#endif /* _MIPSEL */
        } fi_struct;
};
#endif /* _LANGUAGE_C || _LANGUAGE_C_PLUS_PLUS */

/*
 * Constants for the implementation fieid of the fpc_irr structure for the
 * known implementations.
 */
#define IMPLEMENTATION_NONE     0       /* software */
#define IMPLEMENTATION_R2360    1       /* board */
#define IMPLEMENTATION_R2010    2       /* chip */

/*
 * The constant IRR_IMP_MASK is to get at the implementation fieid of the
 * implementation and revision register.  The other constants (IRR_IMP_*)
 * are constants for the known implementations.
 */
#define IRR_IMP_MASK            0x0000ff00

#define IRR_IMP_NONE            0x00000000
#define IRR_IMP_R2360           0x00000100
#define IRR_IMP_R2010           0x00000200

/*
 * Structure and constant definisions for the floating-point control
 * control and status register (fpc_csr).
 */
#if defined(_LANGUAGE_C) || defined(_LANGUAGE_C_PLUS_PLUS)
union fpc_csr {
        unsigned int fc_word;
        struct {
#ifdef _MIPSEB
                unsigned fcc : 7;       /* only used for mips4 */
                unsigned flush : 1;
                unsigned condition : 1;
                unsigned reserved1 : 5;

                unsigned ex_unimplemented : 1;
                unsigned ex_invalid : 1;
                unsigned ex_divide0 : 1;
                unsigned ex_overflow : 1;
                unsigned ex_underflow : 1;
                unsigned ex_inexact : 1;

                unsigned en_invalid : 1;
                unsigned en_divide0 : 1;
                unsigned en_overflow : 1;
                unsigned en_underflow : 1;
                unsigned en_inexact : 1;

                unsigned se_invalid : 1;
                unsigned se_divide0 : 1;
                unsigned se_overflow : 1;
                unsigned se_underflow : 1;
                unsigned se_inexact : 1;

                unsigned rounding_mode : 2;
#endif /* _MIPSEB */
#ifdef _MIPSEL
                unsigned rounding_mode : 2;

                unsigned se_inexact : 1;
                unsigned se_underflow : 1;
                unsigned se_overflow : 1;
                unsigned se_divide0 : 1;
                unsigned se_invalid : 1;

                unsigned en_inexact : 1;
                unsigned en_underflow : 1;
                unsigned en_overflow : 1;
                unsigned en_divide0 : 1;
                unsigned en_invalid : 1;

                unsigned ex_inexact : 1;
                unsigned ex_underflow : 1;
                unsigned ex_overflow : 1;
                unsigned ex_divide0 : 1;
                unsigned ex_invalid : 1;
                unsigned ex_unimplemented : 1;

                unsigned reserved1 : 5;
                unsigned condition : 1;
                unsigned flush : 1;
                unsigned fcc : 7;       /* only used for mips4 */
#endif /* _MIPSEL */
        } fc_struct;
};
#endif /* _LANGUAGE_C || _LANGUAGE_C_PLUS_PLUS */

/*
 * Constants for the rounding_mode field of the fpc_csr
 */
#define ROUND_TO_NEAREST        0
#define ROUND_TO_ZERO           1
#define ROUND_TO_PLUS_INFINITY  2
#define ROUND_TO_MINUS_INFINITY 3

/* Masks to get at the unimplemented exception */
#define FPCSR_FLUSH_ZERO        0x01000000
#define FPCSR_UNIMP             0x00020000
#define FPCSR_EXCEPTIONS        0x0003f000      /* all exceptions */
#define FPCSR_ENABLES           0x00000f80
#define FPCSR_FLAGS             0x0000007c

#ifdef _LANGUAGE_ASSEMBLY
/*
 * Assembly register names for the floating-point control registers.
 */
#define fpc_irr $0
#define fpc_csr $31

#endif /* _LANGUAGE_ASSEMBLY */

#ifdef __cplusplus
}
#endif
#endif /* __SYS_FPU_H__ */