186 lines
6.1 KiB
C
186 lines
6.1 KiB
C
/*---------------------------------------------------------------------------+
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| fpu_emu.h |
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| $Id: fpu_emu.h,v 1.22 2004-02-11 19:40:25 sshwarts Exp $
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| Copyright (C) 1992,1993,1994,1997 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@suburbia.net |
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+---------------------------------------------------------------------------*/
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#ifndef _FPU_EMU_H_
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#define _FPU_EMU_H_
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#include <linux/linkage.h>
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/*
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* Define PECULIAR_486 to get a closer approximation to 80486 behaviour,
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* rather than behaviour which appears to be cleaner.
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* This is a matter of opinion: for all I know, the 80486 may simply
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* be complying with the IEEE spec. Maybe one day I'll get to see the
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* spec...
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*/
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#define PECULIAR_486
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#define EXP_BIAS (0)
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#define EXP_OVER (0x4000) /* smallest invalid large exponent */
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#define EXP_UNDER (-0x3fff) /* largest invalid small exponent */
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#define EXP_WAY_UNDER (-0x6000) /* Below the smallest denormal, but still a 16 bit nr */
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#define EXP_Infinity EXP_OVER
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#define EXP_NaN EXP_OVER
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#define EXTENDED_Ebias (0x3fff)
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#define EXTENDED_Emin (-0x3ffe) /* smallest valid exponent */
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#define SIGN_POS (0)
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#define SIGN_NEG (0x80)
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#define SIGN_Positive (0)
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#define SIGN_Negative (0x8000)
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/* Keep the order TAG_Valid, TAG_Zero, TW_Denormal */
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/* The following fold to 2 (Special) in the Tag Word */
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#define TW_Denormal 4 /* De-normal */
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#define TW_Infinity 5 /* + or - infinity */
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#define TW_NaN 6 /* Not a Number */
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#define TW_Unsupported 7 /* Not supported by an 80486 */
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#define TAG_Valid 0 /* valid */
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#define TAG_Zero 1 /* zero */
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#define TAG_Special 2 /* De-normal, + or - infinity, or NaN */
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#define TAG_Empty 3 /* empty */
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/* Special st() number to identify loaded data (not on stack). */
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#define LOADED_DATA (10101)
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/* A few flags (must be >= 0x10). */
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#define REV 0x10
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#define DEST_RM 0x20
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#define LOADED 0x40
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#define FPU_Exception (0x80000000) /* Added to tag returns. */
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#include "fpu_system.h"
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#define FWAIT_OPCODE 0x9b
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#define OP_SIZE_PREFIX 0x66
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#define ADDR_SIZE_PREFIX 0x67
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#if defined(__MWERKS__) && defined(macintosh)
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#pragma options align=packed
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#endif
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struct address {
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bx_address offset;
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#ifdef EMU_BIG_ENDIAN
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u32 empty:5;
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u32 opcode:11;
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u32 selector:16;
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#else
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u32 selector:16;
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u32 opcode:11;
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u32 empty:5;
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#endif
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} GCC_ATTRIBUTE((packed));
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typedef void (*FUNC)(void);
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typedef void (*FUNC_ST0)(FPU_REG *st0_ptr, u_char st0_tag);
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typedef struct { u_char address_size, operand_size, segment; }
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GCC_ATTRIBUTE((packed)) overrides;
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/* This structure is 32 bits: */
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typedef struct { overrides override;
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u_char default_mode; }
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GCC_ATTRIBUTE((packed)) fpu_addr_modes;
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#if defined(__MWERKS__) && defined(macintosh)
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#pragma options align=reset
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#endif
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/* PROTECTED has a restricted meaning in the emulator; it is used
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to signal that the emulator needs to do special things to ensure
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that protection is respected in a segmented model. */
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#define PROTECTED 4
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#define SIXTEEN 1 /* We rely upon this being 1 (true) */
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#define VM86 SIXTEEN
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#define PM16 (SIXTEEN | PROTECTED)
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#define SEG32 PROTECTED
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#define fpu_register(x) ( *((FPU_REG *)(FPU_register_base + sizeof(FPU_REG) * (x & 7) )))
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#define st(x) ( *((FPU_REG *)(FPU_register_base + sizeof(FPU_REG) * ((FPU_tos+x) & 7) )))
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#define NOT_EMPTY(i) (!FPU_empty_i(i))
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#define NOT_EMPTY_ST0 (st0_tag ^ TAG_Empty)
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/* FPU_push() does not affect the tags */
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#define FPU_push() { FPU_tos--; }
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/* register accessors */
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#ifdef EMU_BIG_ENDIAN
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#define MAKE_REG(s,e,l,h) { 0,0,0, \
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((EXTENDED_Ebias+(e)) | ((SIGN_##s != 0)*0x8000)) , h, l}
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#define signbyte(x) (((u_char *)(x))[6])
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#define significand(x) (((u64 *)&((x)->sigh))[0])
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#else
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#define MAKE_REG(s,e,l,h) { l, h, \
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((EXTENDED_Ebias+(e)) | ((SIGN_##s != 0)*0x8000)), 0,0,0 }
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#define signbyte(x) (((u_char *)(x))[9])
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#define significand(x) (((u64 *)&((x)->sigl))[0])
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#endif
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#define getsign(a) (signbyte(a) & 0x80)
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#define setsign(a,b) { if (b) signbyte(a) |= 0x80; else signbyte(a) &= 0x7f; }
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#define copysign(a,b) { if (getsign(a)) signbyte(b) |= 0x80; \
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else signbyte(b) &= 0x7f; }
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#define changesign(a) { signbyte(a) ^= 0x80; }
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#define setpositive(a) { signbyte(a) &= 0x7f; }
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#define setnegative(a) { signbyte(a) |= 0x80; }
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#define signpositive(a) ( (signbyte(a) & 0x80) == 0 )
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#define signnegative(a) (signbyte(a) & 0x80)
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BX_C_INLINE void reg_copy(FPU_REG const *x, FPU_REG *y)
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{
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y->exp = x->exp;
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significand(y) = significand(x);
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}
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#define exponent(x) (((x)->exp & 0x7fff) - EXTENDED_Ebias)
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#define setexponentpos(x,y) { (x)->exp = ((y) + EXTENDED_Ebias) & 0x7fff; }
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#define exponent16(x) (x)->exp
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#define setexponent16(x,y) { (x)->exp = (y); }
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#define addexponent(x,y) { (x)->exp += (y); }
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#define stdexp(x) { (x)->exp += EXTENDED_Ebias; }
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#define isdenormal(ptr) (exponent(ptr) == EXP_BIAS+EXP_UNDER)
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/*----- Prototypes for functions written in assembler -----*/
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asmlinkage int FPU_normalize_nuo(FPU_REG *x, int bias);
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asmlinkage int FPU_u_sub(FPU_REG const *arg1, FPU_REG const *arg2,
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FPU_REG *answ, u16 control_w, u_char sign,
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s32 expa, s32 expb);
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asmlinkage int FPU_u_mul(FPU_REG const *arg1, FPU_REG const *arg2,
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FPU_REG *answ, u16 control_w, u_char sign,
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s32 expon);
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asmlinkage int FPU_u_div(FPU_REG const *arg1, FPU_REG const *arg2,
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FPU_REG *answ, u16 control_w, u_char sign);
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asmlinkage int FPU_u_add(FPU_REG const *arg1, FPU_REG const *arg2,
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FPU_REG *answ, u16 control_w, u_char sign,
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s32 expa, s32 expb);
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asmlinkage int wm_sqrt(FPU_REG *n, u16 control_w, u_char sign);
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asmlinkage u32 FPU_shrx(void *l, u32 x);
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asmlinkage u32 FPU_shrxs(void *v, u32 x);
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asmlinkage int FPU_round(FPU_REG *arg, u32 extent,
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u16 control_w, u_char sign);
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#ifndef MAKING_PROTO
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#include "fpu_proto.h"
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#endif
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#endif /* !defined _FPU_EMU_H_ */
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