1 /*---------------------------------------------------------------------------+ 2 | fpu_aux.c | 3 | | 4 | Code to implement some of the FPU auxiliary instructions. | 5 | | 6 | Copyright (C) 1992,1993,1994,1997 | 7 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | 8 | E-mail billm@suburbia.net | 9 | | 10 | | 11 +---------------------------------------------------------------------------*/ 12 13 #include "fpu_system.h" 14 #include "exception.h" 15 #include "fpu_emu.h" 16 #include "status_w.h" 17 #include "control_w.h" 18 19 static void fnop(void) 20 { 21 } 22 23 static void fclex(void) 24 { 25 partial_status &= 26 ~(SW_Backward | SW_Summary | SW_Stack_Fault | SW_Precision | 27 SW_Underflow | SW_Overflow | SW_Zero_Div | SW_Denorm_Op | 28 SW_Invalid); 29 no_ip_update = 1; 30 } 31 32 /* Needs to be externally visible */ 33 void finit_soft_fpu(struct i387_soft_struct *soft) 34 { 35 struct address *oaddr, *iaddr; 36 memset(soft, 0, sizeof(*soft)); 37 soft->cwd = 0x037f; 38 soft->swd = 0; 39 soft->ftop = 0; /* We don't keep top in the status word internally. */ 40 soft->twd = 0xffff; 41 /* The behaviour is different from that detailed in 42 Section 15.1.6 of the Intel manual */ 43 oaddr = (struct address *)&soft->foo; 44 oaddr->offset = 0; 45 oaddr->selector = 0; 46 iaddr = (struct address *)&soft->fip; 47 iaddr->offset = 0; 48 iaddr->selector = 0; 49 iaddr->opcode = 0; 50 soft->no_update = 1; 51 } 52 53 void finit(void) 54 { 55 finit_soft_fpu(¤t->thread.fpu.state->soft); 56 } 57 58 /* 59 * These are nops on the i387.. 60 */ 61 #define feni fnop 62 #define fdisi fnop 63 #define fsetpm fnop 64 65 static FUNC const finit_table[] = { 66 feni, fdisi, fclex, finit, 67 fsetpm, FPU_illegal, FPU_illegal, FPU_illegal 68 }; 69 70 void finit_(void) 71 { 72 (finit_table[FPU_rm]) (); 73 } 74 75 static void fstsw_ax(void) 76 { 77 *(short *)&FPU_EAX = status_word(); 78 no_ip_update = 1; 79 } 80 81 static FUNC const fstsw_table[] = { 82 fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal, 83 FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal 84 }; 85 86 void fstsw_(void) 87 { 88 (fstsw_table[FPU_rm]) (); 89 } 90 91 static FUNC const fp_nop_table[] = { 92 fnop, FPU_illegal, FPU_illegal, FPU_illegal, 93 FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal 94 }; 95 96 void fp_nop(void) 97 { 98 (fp_nop_table[FPU_rm]) (); 99 } 100 101 void fld_i_(void) 102 { 103 FPU_REG *st_new_ptr; 104 int i; 105 u_char tag; 106 107 if (STACK_OVERFLOW) { 108 FPU_stack_overflow(); 109 return; 110 } 111 112 /* fld st(i) */ 113 i = FPU_rm; 114 if (NOT_EMPTY(i)) { 115 reg_copy(&st(i), st_new_ptr); 116 tag = FPU_gettagi(i); 117 push(); 118 FPU_settag0(tag); 119 } else { 120 if (control_word & CW_Invalid) { 121 /* The masked response */ 122 FPU_stack_underflow(); 123 } else 124 EXCEPTION(EX_StackUnder); 125 } 126 127 } 128 129 void fxch_i(void) 130 { 131 /* fxch st(i) */ 132 FPU_REG t; 133 int i = FPU_rm; 134 FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i); 135 long tag_word = fpu_tag_word; 136 int regnr = top & 7, regnri = ((regnr + i) & 7); 137 u_char st0_tag = (tag_word >> (regnr * 2)) & 3; 138 u_char sti_tag = (tag_word >> (regnri * 2)) & 3; 139 140 if (st0_tag == TAG_Empty) { 141 if (sti_tag == TAG_Empty) { 142 FPU_stack_underflow(); 143 FPU_stack_underflow_i(i); 144 return; 145 } 146 if (control_word & CW_Invalid) { 147 /* Masked response */ 148 FPU_copy_to_reg0(sti_ptr, sti_tag); 149 } 150 FPU_stack_underflow_i(i); 151 return; 152 } 153 if (sti_tag == TAG_Empty) { 154 if (control_word & CW_Invalid) { 155 /* Masked response */ 156 FPU_copy_to_regi(st0_ptr, st0_tag, i); 157 } 158 FPU_stack_underflow(); 159 return; 160 } 161 clear_C1(); 162 163 reg_copy(st0_ptr, &t); 164 reg_copy(sti_ptr, st0_ptr); 165 reg_copy(&t, sti_ptr); 166 167 tag_word &= ~(3 << (regnr * 2)) & ~(3 << (regnri * 2)); 168 tag_word |= (sti_tag << (regnr * 2)) | (st0_tag << (regnri * 2)); 169 fpu_tag_word = tag_word; 170 } 171 172 void ffree_(void) 173 { 174 /* ffree st(i) */ 175 FPU_settagi(FPU_rm, TAG_Empty); 176 } 177 178 void ffreep(void) 179 { 180 /* ffree st(i) + pop - unofficial code */ 181 FPU_settagi(FPU_rm, TAG_Empty); 182 FPU_pop(); 183 } 184 185 void fst_i_(void) 186 { 187 /* fst st(i) */ 188 FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); 189 } 190 191 void fstp_i(void) 192 { 193 /* fstp st(i) */ 194 FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); 195 FPU_pop(); 196 } 197