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(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 static void fstsw_ax(void) 67 { 68 *(short *)&FPU_EAX = status_word(); 69 no_ip_update = 1; 70 } 71 72 static FUNC const fstsw_table[] = { 73 fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal, 74 FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal 75 }; 76 77 void fstsw_(void) 78 { 79 (fstsw_table[FPU_rm]) (); 80 } 81 82 static FUNC const fp_nop_table[] = { 83 fnop, FPU_illegal, FPU_illegal, FPU_illegal, 84 FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal 85 }; 86 87 void fp_nop(void) 88 { 89 (fp_nop_table[FPU_rm]) (); 90 } 91 92 void fld_i_(void) 93 { 94 FPU_REG *st_new_ptr; 95 int i; 96 u_char tag; 97 98 if (STACK_OVERFLOW) { 99 FPU_stack_overflow(); 100 return; 101 } 102 103 /* fld st(i) */ 104 i = FPU_rm; 105 if (NOT_EMPTY(i)) { 106 reg_copy(&st(i), st_new_ptr); 107 tag = FPU_gettagi(i); 108 push(); 109 FPU_settag0(tag); 110 } else { 111 if (control_word & CW_Invalid) { 112 /* The masked response */ 113 FPU_stack_underflow(); 114 } else 115 EXCEPTION(EX_StackUnder); 116 } 117 118 } 119 120 void fxch_i(void) 121 { 122 /* fxch st(i) */ 123 FPU_REG t; 124 int i = FPU_rm; 125 FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i); 126 long tag_word = fpu_tag_word; 127 int regnr = top & 7, regnri = ((regnr + i) & 7); 128 u_char st0_tag = (tag_word >> (regnr * 2)) & 3; 129 u_char sti_tag = (tag_word >> (regnri * 2)) & 3; 130 131 if (st0_tag == TAG_Empty) { 132 if (sti_tag == TAG_Empty) { 133 FPU_stack_underflow(); 134 FPU_stack_underflow_i(i); 135 return; 136 } 137 if (control_word & CW_Invalid) { 138 /* Masked response */ 139 FPU_copy_to_reg0(sti_ptr, sti_tag); 140 } 141 FPU_stack_underflow_i(i); 142 return; 143 } 144 if (sti_tag == TAG_Empty) { 145 if (control_word & CW_Invalid) { 146 /* Masked response */ 147 FPU_copy_to_regi(st0_ptr, st0_tag, i); 148 } 149 FPU_stack_underflow(); 150 return; 151 } 152 clear_C1(); 153 154 reg_copy(st0_ptr, &t); 155 reg_copy(sti_ptr, st0_ptr); 156 reg_copy(&t, sti_ptr); 157 158 tag_word &= ~(3 << (regnr * 2)) & ~(3 << (regnri * 2)); 159 tag_word |= (sti_tag << (regnr * 2)) | (st0_tag << (regnri * 2)); 160 fpu_tag_word = tag_word; 161 } 162 163 void ffree_(void) 164 { 165 /* ffree st(i) */ 166 FPU_settagi(FPU_rm, TAG_Empty); 167 } 168 169 void ffreep(void) 170 { 171 /* ffree st(i) + pop - unofficial code */ 172 FPU_settagi(FPU_rm, TAG_Empty); 173 FPU_pop(); 174 } 175 176 void fst_i_(void) 177 { 178 /* fst st(i) */ 179 FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); 180 } 181 182 void fstp_i(void) 183 { 184 /* fstp st(i) */ 185 FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm); 186 FPU_pop(); 187 } 188