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 20 static void fnop(void) 21 { 22 } 23 24 static void fclex(void) 25 { 26 partial_status &= ~(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(void) 34 { 35 control_word = 0x037f; 36 partial_status = 0; 37 top = 0; /* We don't keep top in the status word internally. */ 38 fpu_tag_word = 0xffff; 39 /* The behaviour is different from that detailed in 40 Section 15.1.6 of the Intel manual */ 41 operand_address.offset = 0; 42 operand_address.selector = 0; 43 instruction_address.offset = 0; 44 instruction_address.selector = 0; 45 instruction_address.opcode = 0; 46 no_ip_update = 1; 47 } 48 49 /* 50 * These are nops on the i387.. 51 */ 52 #define feni fnop 53 #define fdisi fnop 54 #define fsetpm fnop 55 56 static FUNC const finit_table[] = { 57 feni, fdisi, fclex, finit, 58 fsetpm, FPU_illegal, FPU_illegal, FPU_illegal 59 }; 60 61 void finit_(void) 62 { 63 (finit_table[FPU_rm])(); 64 } 65 66 67 static void fstsw_ax(void) 68 { 69 *(short *) &FPU_EAX = status_word(); 70 no_ip_update = 1; 71 } 72 73 static FUNC const fstsw_table[] = { 74 fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal, 75 FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal 76 }; 77 78 void fstsw_(void) 79 { 80 (fstsw_table[FPU_rm])(); 81 } 82 83 84 static FUNC const fp_nop_table[] = { 85 fnop, FPU_illegal, FPU_illegal, FPU_illegal, 86 FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal 87 }; 88 89 void fp_nop(void) 90 { 91 (fp_nop_table[FPU_rm])(); 92 } 93 94 95 void fld_i_(void) 96 { 97 FPU_REG *st_new_ptr; 98 int i; 99 u_char tag; 100 101 if ( STACK_OVERFLOW ) 102 { FPU_stack_overflow(); return; } 103 104 /* fld st(i) */ 105 i = FPU_rm; 106 if ( NOT_EMPTY(i) ) 107 { 108 reg_copy(&st(i), st_new_ptr); 109 tag = FPU_gettagi(i); 110 push(); 111 FPU_settag0(tag); 112 } 113 else 114 { 115 if ( control_word & CW_Invalid ) 116 { 117 /* The masked response */ 118 FPU_stack_underflow(); 119 } 120 else 121 EXCEPTION(EX_StackUnder); 122 } 123 124 } 125 126 127 void fxch_i(void) 128 { 129 /* fxch st(i) */ 130 FPU_REG t; 131 int i = FPU_rm; 132 FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i); 133 long tag_word = fpu_tag_word; 134 int regnr = top & 7, regnri = ((regnr + i) & 7); 135 u_char st0_tag = (tag_word >> (regnr*2)) & 3; 136 u_char sti_tag = (tag_word >> (regnri*2)) & 3; 137 138 if ( st0_tag == TAG_Empty ) 139 { 140 if ( sti_tag == TAG_Empty ) 141 { 142 FPU_stack_underflow(); 143 FPU_stack_underflow_i(i); 144 return; 145 } 146 if ( control_word & CW_Invalid ) 147 { 148 /* Masked response */ 149 FPU_copy_to_reg0(sti_ptr, sti_tag); 150 } 151 FPU_stack_underflow_i(i); 152 return; 153 } 154 if ( sti_tag == TAG_Empty ) 155 { 156 if ( control_word & CW_Invalid ) 157 { 158 /* Masked response */ 159 FPU_copy_to_regi(st0_ptr, st0_tag, i); 160 } 161 FPU_stack_underflow(); 162 return; 163 } 164 clear_C1(); 165 166 reg_copy(st0_ptr, &t); 167 reg_copy(sti_ptr, st0_ptr); 168 reg_copy(&t, sti_ptr); 169 170 tag_word &= ~(3 << (regnr*2)) & ~(3 << (regnri*2)); 171 tag_word |= (sti_tag << (regnr*2)) | (st0_tag << (regnri*2)); 172 fpu_tag_word = tag_word; 173 } 174 175 176 void ffree_(void) 177 { 178 /* ffree st(i) */ 179 FPU_settagi(FPU_rm, TAG_Empty); 180 } 181 182 183 void ffreep(void) 184 { 185 /* ffree st(i) + pop - unofficial code */ 186 FPU_settagi(FPU_rm, TAG_Empty); 187 FPU_pop(); 188 } 189 190 191 void fst_i_(void) 192 { 193 /* fst st(i) */ 194 FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); 195 } 196 197 198 void fstp_i(void) 199 { 200 /* fstp st(i) */ 201 FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); 202 FPU_pop(); 203 } 204 205