1 /////////////////////////////////////////////////////////////////////////
2 // $Id: fpu_misc.cc 13466 2018-02-16 07:57:32Z sshwarts $
3 /////////////////////////////////////////////////////////////////////////
4 //
5 // Copyright (c) 2003-2018 Stanislav Shwartsman
6 // Written by Stanislav Shwartsman [sshwarts at sourceforge net]
7 //
8 // This library is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU Lesser General Public
10 // License as published by the Free Software Foundation; either
11 // version 2 of the License, or (at your option) any later version.
12 //
13 // This library is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // Lesser General Public License for more details.
17 //
18 // You should have received a copy of the GNU Lesser General Public
19 // License along with this library; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 //
22 /////////////////////////////////////////////////////////////////////////
23
24 #define NEED_CPU_REG_SHORTCUTS 1
25 #include "bochs.h"
26 #include "cpu/cpu.h"
27 #define LOG_THIS BX_CPU_THIS_PTR
28
29 #if BX_SUPPORT_FPU
30
31 #include "softfloatx80.h"
32
33 /* D9 C8 */
FXCH_STi(bxInstruction_c * i)34 void BX_CPP_AttrRegparmN(1) BX_CPU_C::FXCH_STi(bxInstruction_c *i)
35 {
36 BX_CPU_THIS_PTR prepareFPU(i);
37 BX_CPU_THIS_PTR FPU_update_last_instruction(i);
38
39 int st0_tag = BX_CPU_THIS_PTR the_i387.FPU_gettagi(0);
40 int sti_tag = BX_CPU_THIS_PTR the_i387.FPU_gettagi(i->src());
41
42 floatx80 st0_reg = BX_READ_FPU_REG(0);
43 floatx80 sti_reg = BX_READ_FPU_REG(i->src());
44
45 clear_C1();
46
47 if (st0_tag == FPU_Tag_Empty || sti_tag == FPU_Tag_Empty)
48 {
49 FPU_exception(i, FPU_EX_Stack_Underflow);
50
51 if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
52 {
53 /* Masked response */
54 if (st0_tag == FPU_Tag_Empty)
55 st0_reg = floatx80_default_nan;
56
57 if (sti_tag == FPU_Tag_Empty)
58 sti_reg = floatx80_default_nan;
59 }
60 else {
61 BX_NEXT_INSTR(i);
62 }
63 }
64
65 BX_WRITE_FPU_REG(st0_reg, i->src());
66 BX_WRITE_FPU_REG(sti_reg, 0);
67
68 BX_NEXT_INSTR(i);
69 }
70
71 /* D9 E0 */
FCHS(bxInstruction_c * i)72 void BX_CPP_AttrRegparmN(1) BX_CPU_C::FCHS(bxInstruction_c *i)
73 {
74 BX_CPU_THIS_PTR prepareFPU(i);
75 BX_CPU_THIS_PTR FPU_update_last_instruction(i);
76
77 if (IS_TAG_EMPTY(0)) {
78 FPU_stack_underflow(i, 0);
79 }
80 else {
81 clear_C1();
82 floatx80 st0_reg = BX_READ_FPU_REG(0);
83 BX_WRITE_FPU_REG(floatx80_chs(st0_reg), 0);
84 }
85
86 BX_NEXT_INSTR(i);
87 }
88
89 /* D9 E1 */
FABS(bxInstruction_c * i)90 void BX_CPP_AttrRegparmN(1) BX_CPU_C::FABS(bxInstruction_c *i)
91 {
92 BX_CPU_THIS_PTR prepareFPU(i);
93 BX_CPU_THIS_PTR FPU_update_last_instruction(i);
94
95 if (IS_TAG_EMPTY(0)) {
96 FPU_stack_underflow(i, 0);
97 }
98 else {
99 clear_C1();
100 floatx80 st0_reg = BX_READ_FPU_REG(0);
101 BX_WRITE_FPU_REG(floatx80_abs(st0_reg), 0);
102 }
103
104 BX_NEXT_INSTR(i);
105 }
106
107 /* D9 F6 */
FDECSTP(bxInstruction_c * i)108 void BX_CPP_AttrRegparmN(1) BX_CPU_C::FDECSTP(bxInstruction_c *i)
109 {
110 BX_CPU_THIS_PTR prepareFPU(i);
111 BX_CPU_THIS_PTR FPU_update_last_instruction(i);
112
113 clear_C1();
114
115 BX_CPU_THIS_PTR the_i387.tos = (BX_CPU_THIS_PTR the_i387.tos-1) & 7;
116
117 BX_NEXT_INSTR(i);
118 }
119
120 /* D9 F7 */
FINCSTP(bxInstruction_c * i)121 void BX_CPP_AttrRegparmN(1) BX_CPU_C::FINCSTP(bxInstruction_c *i)
122 {
123 BX_CPU_THIS_PTR prepareFPU(i);
124 BX_CPU_THIS_PTR FPU_update_last_instruction(i);
125
126 clear_C1();
127
128 BX_CPU_THIS_PTR the_i387.tos = (BX_CPU_THIS_PTR the_i387.tos+1) & 7;
129
130 BX_NEXT_INSTR(i);
131 }
132
133 /* DD C0 */
FFREE_STi(bxInstruction_c * i)134 void BX_CPP_AttrRegparmN(1) BX_CPU_C::FFREE_STi(bxInstruction_c *i)
135 {
136 BX_CPU_THIS_PTR prepareFPU(i);
137 BX_CPU_THIS_PTR FPU_update_last_instruction(i);
138
139 clear_C1();
140
141 BX_CPU_THIS_PTR the_i387.FPU_settagi(FPU_Tag_Empty, i->dst());
142
143 BX_NEXT_INSTR(i);
144 }
145
146 /*
147 * Free the st(0) register and pop it from the FPU stack.
148 * "Undocumented" by Intel & AMD but mentioned in AMDs Athlon Docs.
149 */
150
151 /* DF C0 */
FFREEP_STi(bxInstruction_c * i)152 void BX_CPP_AttrRegparmN(1) BX_CPU_C::FFREEP_STi(bxInstruction_c *i)
153 {
154 BX_CPU_THIS_PTR prepareFPU(i);
155 BX_CPU_THIS_PTR FPU_update_last_instruction(i);
156
157 clear_C1();
158
159 BX_CPU_THIS_PTR the_i387.FPU_settagi(FPU_Tag_Empty, i->dst());
160 BX_CPU_THIS_PTR the_i387.FPU_pop();
161
162 BX_NEXT_INSTR(i);
163 }
164
165 #endif
166