1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /*---------------------------------------------------------------------------+ 3 | fpu_emu.h | 4 | | 5 | Copyright (C) 1992,1993,1994,1997 | 6 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | 7 | Australia. E-mail billm@suburbia.net | 8 | | 9 +---------------------------------------------------------------------------*/ 10 11 #ifndef _FPU_EMU_H_ 12 #define _FPU_EMU_H_ 13 14 /* 15 * Define PECULIAR_486 to get a closer approximation to 80486 behaviour, 16 * rather than behaviour which appears to be cleaner. 17 * This is a matter of opinion: for all I know, the 80486 may simply 18 * be complying with the IEEE spec. Maybe one day I'll get to see the 19 * spec... 20 */ 21 #define PECULIAR_486 22 23 #ifdef __ASSEMBLY__ 24 #include "fpu_asm.h" 25 #define Const(x) $##x 26 #else 27 #define Const(x) x 28 #endif 29 30 #define EXP_BIAS Const(0) 31 #define EXP_OVER Const(0x4000) /* smallest invalid large exponent */ 32 #define EXP_UNDER Const(-0x3fff) /* largest invalid small exponent */ 33 #define EXP_WAY_UNDER Const(-0x6000) /* Below the smallest denormal, but 34 still a 16 bit nr. */ 35 #define EXP_Infinity EXP_OVER 36 #define EXP_NaN EXP_OVER 37 38 #define EXTENDED_Ebias Const(0x3fff) 39 #define EXTENDED_Emin (-0x3ffe) /* smallest valid exponent */ 40 41 #define SIGN_POS Const(0) 42 #define SIGN_NEG Const(0x80) 43 44 #define SIGN_Positive Const(0) 45 #define SIGN_Negative Const(0x8000) 46 47 /* Keep the order TAG_Valid, TAG_Zero, TW_Denormal */ 48 /* The following fold to 2 (Special) in the Tag Word */ 49 #define TW_Denormal Const(4) /* De-normal */ 50 #define TW_Infinity Const(5) /* + or - infinity */ 51 #define TW_NaN Const(6) /* Not a Number */ 52 #define TW_Unsupported Const(7) /* Not supported by an 80486 */ 53 54 #define TAG_Valid Const(0) /* valid */ 55 #define TAG_Zero Const(1) /* zero */ 56 #define TAG_Special Const(2) /* De-normal, + or - infinity, 57 or Not a Number */ 58 #define TAG_Empty Const(3) /* empty */ 59 #define TAG_Error Const(0x80) /* probably need to abort */ 60 61 #define LOADED_DATA Const(10101) /* Special st() number to identify 62 loaded data (not on stack). */ 63 64 /* A few flags (must be >= 0x10). */ 65 #define REV 0x10 66 #define DEST_RM 0x20 67 #define LOADED 0x40 68 69 #define FPU_Exception Const(0x80000000) /* Added to tag returns. */ 70 71 #ifndef __ASSEMBLY__ 72 73 #include "fpu_system.h" 74 75 #include <uapi/asm/sigcontext.h> /* for struct _fpstate */ 76 #include <asm/math_emu.h> 77 #include <linux/linkage.h> 78 79 /* 80 #define RE_ENTRANT_CHECKING 81 */ 82 83 #ifdef RE_ENTRANT_CHECKING 84 extern u_char emulating; 85 # define RE_ENTRANT_CHECK_OFF emulating = 0 86 # define RE_ENTRANT_CHECK_ON emulating = 1 87 #else 88 # define RE_ENTRANT_CHECK_OFF 89 # define RE_ENTRANT_CHECK_ON 90 #endif /* RE_ENTRANT_CHECKING */ 91 92 #define FWAIT_OPCODE 0x9b 93 #define OP_SIZE_PREFIX 0x66 94 #define ADDR_SIZE_PREFIX 0x67 95 #define PREFIX_CS 0x2e 96 #define PREFIX_DS 0x3e 97 #define PREFIX_ES 0x26 98 #define PREFIX_SS 0x36 99 #define PREFIX_FS 0x64 100 #define PREFIX_GS 0x65 101 #define PREFIX_REPE 0xf3 102 #define PREFIX_REPNE 0xf2 103 #define PREFIX_LOCK 0xf0 104 #define PREFIX_CS_ 1 105 #define PREFIX_DS_ 2 106 #define PREFIX_ES_ 3 107 #define PREFIX_FS_ 4 108 #define PREFIX_GS_ 5 109 #define PREFIX_SS_ 6 110 #define PREFIX_DEFAULT 7 111 112 struct address { 113 unsigned int offset; 114 unsigned int selector:16; 115 unsigned int opcode:11; 116 unsigned int empty:5; 117 }; 118 struct fpu__reg { 119 unsigned sigl; 120 unsigned sigh; 121 short exp; 122 }; 123 124 typedef void (*FUNC) (void); 125 typedef struct fpu__reg FPU_REG; 126 typedef void (*FUNC_ST0) (FPU_REG *st0_ptr, u_char st0_tag); 127 typedef struct { 128 u_char address_size, operand_size, segment; 129 } overrides; 130 /* This structure is 32 bits: */ 131 typedef struct { 132 overrides override; 133 u_char default_mode; 134 } fpu_addr_modes; 135 /* PROTECTED has a restricted meaning in the emulator; it is used 136 to signal that the emulator needs to do special things to ensure 137 that protection is respected in a segmented model. */ 138 #define PROTECTED 4 139 #define SIXTEEN 1 /* We rely upon this being 1 (true) */ 140 #define VM86 SIXTEEN 141 #define PM16 (SIXTEEN | PROTECTED) 142 #define SEG32 PROTECTED 143 extern u_char const data_sizes_16[32]; 144 145 #define register_base ((u_char *) registers ) 146 #define fpu_register(x) ( * ((FPU_REG *)( register_base + 10 * (x & 7) )) ) 147 #define st(x) ( * ((FPU_REG *)( register_base + 10 * ((top+x) & 7) )) ) 148 149 #define STACK_OVERFLOW (FPU_stackoverflow(&st_new_ptr)) 150 #define NOT_EMPTY(i) (!FPU_empty_i(i)) 151 152 #define NOT_EMPTY_ST0 (st0_tag ^ TAG_Empty) 153 154 #define poppop() { FPU_pop(); FPU_pop(); } 155 156 /* push() does not affect the tags */ 157 #define push() { top--; } 158 159 #define signbyte(a) (((u_char *)(a))[9]) 160 #define getsign(a) (signbyte(a) & 0x80) 161 #define setsign(a,b) { if ((b) != 0) signbyte(a) |= 0x80; else signbyte(a) &= 0x7f; } 162 #define copysign(a,b) { if (getsign(a)) signbyte(b) |= 0x80; \ 163 else signbyte(b) &= 0x7f; } 164 #define changesign(a) { signbyte(a) ^= 0x80; } 165 #define setpositive(a) { signbyte(a) &= 0x7f; } 166 #define setnegative(a) { signbyte(a) |= 0x80; } 167 #define signpositive(a) ( (signbyte(a) & 0x80) == 0 ) 168 #define signnegative(a) (signbyte(a) & 0x80) 169 170 static inline void reg_copy(FPU_REG const *x, FPU_REG *y) 171 { 172 *(short *)&(y->exp) = *(const short *)&(x->exp); 173 *(long long *)&(y->sigl) = *(const long long *)&(x->sigl); 174 } 175 176 #define exponent(x) (((*(short *)&((x)->exp)) & 0x7fff) - EXTENDED_Ebias) 177 #define setexponentpos(x,y) { (*(short *)&((x)->exp)) = \ 178 ((y) + EXTENDED_Ebias) & 0x7fff; } 179 #define exponent16(x) (*(short *)&((x)->exp)) 180 #define setexponent16(x,y) { (*(short *)&((x)->exp)) = (y); } 181 #define addexponent(x,y) { (*(short *)&((x)->exp)) += (y); } 182 #define stdexp(x) { (*(short *)&((x)->exp)) += EXTENDED_Ebias; } 183 184 #define isdenormal(ptr) (exponent(ptr) == EXP_BIAS+EXP_UNDER) 185 186 #define significand(x) ( ((unsigned long long *)&((x)->sigl))[0] ) 187 188 /*----- Prototypes for functions written in assembler -----*/ 189 /* extern void reg_move(FPU_REG *a, FPU_REG *b); */ 190 191 asmlinkage int FPU_normalize(FPU_REG *x); 192 asmlinkage int FPU_normalize_nuo(FPU_REG *x); 193 asmlinkage int FPU_u_sub(FPU_REG const *arg1, FPU_REG const *arg2, 194 FPU_REG * answ, unsigned int control_w, u_char sign, 195 int expa, int expb); 196 asmlinkage int FPU_u_mul(FPU_REG const *arg1, FPU_REG const *arg2, 197 FPU_REG * answ, unsigned int control_w, u_char sign, 198 int expon); 199 asmlinkage int FPU_u_div(FPU_REG const *arg1, FPU_REG const *arg2, 200 FPU_REG * answ, unsigned int control_w, u_char sign); 201 asmlinkage int FPU_u_add(FPU_REG const *arg1, FPU_REG const *arg2, 202 FPU_REG * answ, unsigned int control_w, u_char sign, 203 int expa, int expb); 204 asmlinkage int wm_sqrt(FPU_REG *n, int dummy1, int dummy2, 205 unsigned int control_w, u_char sign); 206 asmlinkage unsigned FPU_shrx(void *l, unsigned x); 207 asmlinkage unsigned FPU_shrxs(void *v, unsigned x); 208 asmlinkage unsigned long FPU_div_small(unsigned long long *x, unsigned long y); 209 asmlinkage int FPU_round(FPU_REG *arg, unsigned int extent, int dummy, 210 unsigned int control_w, u_char sign); 211 212 #ifndef MAKING_PROTO 213 #include "fpu_proto.h" 214 #endif 215 216 #endif /* __ASSEMBLY__ */ 217 218 #endif /* _FPU_EMU_H_ */ 219