Bochs/bochs/cpu/i387.h

#ifndef BX_I387_RELATED_EXTENSIONS_H
#define BX_I387_RELATED_EXTENSIONS_H

#if BX_SUPPORT_FPU

//
// Minimal i387 structure
//
struct i387_t {
    Bit32s cwd;		 // control word
    Bit32s swd;		 // status word
    Bit32s twd;		 // tag word
    Bit32s fip;
    Bit32s fcs;
    Bit32s foo;
    Bit32s fos;
    Bit32s aligment;	 
    Bit64u st_space[16]; // 8*16 bytes per FP-reg (aligned) = 128 bytes
    unsigned char tos;
    unsigned char no_update;
    unsigned char rm;
    unsigned char alimit;
};

// Endian  Host byte order         Guest (x86) byte order
// ======================================================
// Little  FFFFFFFFEEAAAAAA        FFFFFFFFEEAAAAAA
// Big     AAAAAAEEFFFFFFFF        FFFFFFFFEEAAAAAA
//
// Legend: F - fraction/mmx
//         E - exponent
//         A - aligment

#ifdef BX_BIG_ENDIAN
struct BxFpuRegister {
  Bit16u aligment1, aligment2, aligment3;
  Bit16s exp;   /* Signed quantity used in internal arithmetic. */
  Bit32u sigh;
  Bit32u sigl;
} GCC_ATTRIBUTE((aligned(16), packed));
#else
struct BxFpuRegister {
  Bit32u sigl;
  Bit32u sigh;
  Bit16s exp;   /* Signed quantity used in internal arithmetic. */
  Bit16u aligment1, aligment2, aligment3;
} GCC_ATTRIBUTE((aligned(16), packed));
#endif

#define BX_FPU_REG(index) \
    (BX_CPU_THIS_PTR the_i387.st_space[index*2])

#define FPU_PARTIAL_STATUS     (BX_CPU_THIS_PTR the_i387.swd)
#define FPU_TWD                (BX_CPU_THIS_PTR the_i387.twd)
#define FPU_TOS                (BX_CPU_THIS_PTR the_i387.tos)


#if BX_SUPPORT_MMX

typedef union {
  Bit8u u8;
  Bit8s s8;
} MMX_BYTE;

typedef union {
  Bit16u u16;
  Bit16s s16;
  struct {
#ifdef BX_BIG_ENDIAN
    MMX_BYTE hi;
    MMX_BYTE lo;
#else
    MMX_BYTE lo;
    MMX_BYTE hi;
#endif
  } bytes;
} MMX_WORD;

typedef union {
  Bit32u u32;
  Bit32s s32;
  struct {
#ifdef BX_BIG_ENDIAN
    MMX_WORD hi;
    MMX_WORD lo;
#else
    MMX_WORD lo;
    MMX_WORD hi;
#endif
  } words;
} MMX_DWORD;

typedef union {
  Bit64u u64;
  Bit64s s64;
  struct {
#ifdef BX_BIG_ENDIAN
    MMX_DWORD hi;
    MMX_DWORD lo;
#else
    MMX_DWORD lo;
    MMX_DWORD hi;
#endif
  } dwords;
} MMX_QWORD, BxPackedMmxRegister;

#define MMXSB0(reg) (reg.dwords.lo.words.lo.bytes.lo.s8)
#define MMXSB1(reg) (reg.dwords.lo.words.lo.bytes.hi.s8)
#define MMXSB2(reg) (reg.dwords.lo.words.hi.bytes.lo.s8)
#define MMXSB3(reg) (reg.dwords.lo.words.hi.bytes.hi.s8)
#define MMXSB4(reg) (reg.dwords.hi.words.lo.bytes.lo.s8)
#define MMXSB5(reg) (reg.dwords.hi.words.lo.bytes.hi.s8)
#define MMXSB6(reg) (reg.dwords.hi.words.hi.bytes.lo.s8)
#define MMXSB7(reg) (reg.dwords.hi.words.hi.bytes.hi.s8)

#define MMXUB0(reg) (reg.dwords.lo.words.lo.bytes.lo.u8)
#define MMXUB1(reg) (reg.dwords.lo.words.lo.bytes.hi.u8)
#define MMXUB2(reg) (reg.dwords.lo.words.hi.bytes.lo.u8)
#define MMXUB3(reg) (reg.dwords.lo.words.hi.bytes.hi.u8)
#define MMXUB4(reg) (reg.dwords.hi.words.lo.bytes.lo.u8)
#define MMXUB5(reg) (reg.dwords.hi.words.lo.bytes.hi.u8)
#define MMXUB6(reg) (reg.dwords.hi.words.hi.bytes.lo.u8)
#define MMXUB7(reg) (reg.dwords.hi.words.hi.bytes.hi.u8)

#define MMXSW0(reg) (reg.dwords.lo.words.lo.s16)
#define MMXSW1(reg) (reg.dwords.lo.words.hi.s16)
#define MMXSW2(reg) (reg.dwords.hi.words.lo.s16)
#define MMXSW3(reg) (reg.dwords.hi.words.hi.s16)

#define MMXUW0(reg) (reg.dwords.lo.words.lo.u16)
#define MMXUW1(reg) (reg.dwords.lo.words.hi.u16)
#define MMXUW2(reg) (reg.dwords.hi.words.lo.u16)
#define MMXUW3(reg) (reg.dwords.hi.words.hi.u16)
                                
#define MMXSD0(reg) (reg.dwords.lo.s32)
#define MMXSD1(reg) (reg.dwords.hi.s32)

#define MMXUD0(reg) (reg.dwords.lo.u32)
#define MMXUD1(reg) (reg.dwords.hi.u32)

#define MMXSQ(reg)  (reg.s64)
#define MMXUQ(reg)  (reg.u64)

// Endian  Host byte order         Guest (x86) byte order
// ======================================================
// Little  FFFFFFFFEEAAAAAA        FFFFFFFFEEAAAAAA
// Big     AAAAAAEEFFFFFFFF        FFFFFFFFEEAAAAAA
//
// Legend: F - fraction/mmx
//         E - exponent
//         A - aligment

#ifdef BX_BIG_ENDIAN
struct bx_mmx_reg_t {
   Bit16u aligment1, aligment2, aligment3; 
   Bit16u exp; /* 2 byte FP-reg exponent */
   BxPackedMmxRegister packed_mmx_register;
} GCC_ATTRIBUTE((aligned(16), packed));
#else
struct bx_mmx_reg_t {
   BxPackedMmxRegister packed_mmx_register;
   Bit16u exp; /* 2 byte FP reg exponent */
   Bit16u aligment1, aligment2, aligment3; 
} GCC_ATTRIBUTE((aligned(16), packed));
#endif

#define BX_MMX_REG(index) 						\
    (((bx_mmx_reg_t*)(BX_CPU_THIS_PTR the_i387.st_space))[index])

#define BX_READ_MMX_REG(index) 						\
    ((BX_MMX_REG(index)).packed_mmx_register)

#define BX_WRITE_MMX_REG(index, value)            			\
{                                 					\
   (BX_MMX_REG(index)).packed_mmx_register = value;			\
   (BX_MMX_REG(index)).exp = 0xffff;       				\
}                                                      

#endif 		/* BX_SUPPORT_MMX */

#endif		/* BX_SUPPORT_FPU */

#endif