1 /*---------------------------------------------------------------------------+
2 | fpu_tags.c |
3 | |
4 | Set FPU register tags. |
5 | |
6 | Copyright (C) 1997 |
7 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
8 | E-mail billm@jacobi.maths.monash.edu.au |
9 | |
10 | |
11 +---------------------------------------------------------------------------*/
12
13 #include "fpu_emu.h"
14 #include "fpu_system.h"
15 #include "exception.h"
16
17
FPU_pop(void)18 void FPU_pop(void)
19 {
20 fpu_tag_word |= 3 << ((top & 7)*2);
21 top++;
22 }
23
24
FPU_gettag0(void)25 int FPU_gettag0(void)
26 {
27 return (fpu_tag_word >> ((top & 7)*2)) & 3;
28 }
29
30
FPU_gettagi(int stnr)31 int FPU_gettagi(int stnr)
32 {
33 return (fpu_tag_word >> (((top+stnr) & 7)*2)) & 3;
34 }
35
36
FPU_gettag(int regnr)37 int FPU_gettag(int regnr)
38 {
39 return (fpu_tag_word >> ((regnr & 7)*2)) & 3;
40 }
41
42
FPU_settag0(int tag)43 void FPU_settag0(int tag)
44 {
45 int regnr = top;
46 regnr &= 7;
47 fpu_tag_word &= ~(3 << (regnr*2));
48 fpu_tag_word |= (tag & 3) << (regnr*2);
49 }
50
51
FPU_settagi(int stnr,int tag)52 void FPU_settagi(int stnr, int tag)
53 {
54 int regnr = stnr+top;
55 regnr &= 7;
56 fpu_tag_word &= ~(3 << (regnr*2));
57 fpu_tag_word |= (tag & 3) << (regnr*2);
58 }
59
60
FPU_settag(int regnr,int tag)61 void FPU_settag(int regnr, int tag)
62 {
63 regnr &= 7;
64 fpu_tag_word &= ~(3 << (regnr*2));
65 fpu_tag_word |= (tag & 3) << (regnr*2);
66 }
67
68
FPU_Special(FPU_REG const * ptr)69 int FPU_Special(FPU_REG const *ptr)
70 {
71 int exp = exponent(ptr);
72
73 if ( exp == EXP_BIAS+EXP_UNDER )
74 return TW_Denormal;
75 else if ( exp != EXP_BIAS+EXP_OVER )
76 return TW_NaN;
77 else if ( (ptr->sigh == 0x80000000) && (ptr->sigl == 0) )
78 return TW_Infinity;
79 return TW_NaN;
80 }
81
82
isNaN(FPU_REG const * ptr)83 int isNaN(FPU_REG const *ptr)
84 {
85 return ( (exponent(ptr) == EXP_BIAS+EXP_OVER)
86 && !((ptr->sigh == 0x80000000) && (ptr->sigl == 0)) );
87 }
88
89
FPU_empty_i(int stnr)90 int FPU_empty_i(int stnr)
91 {
92 int regnr = (top+stnr) & 7;
93
94 return ((fpu_tag_word >> (regnr*2)) & 3) == TAG_Empty;
95 }
96
97
FPU_stackoverflow(FPU_REG ** st_new_ptr)98 int FPU_stackoverflow(FPU_REG **st_new_ptr)
99 {
100 *st_new_ptr = &st(-1);
101
102 return ((fpu_tag_word >> (((top - 1) & 7)*2)) & 3) != TAG_Empty;
103 }
104
105
FPU_copy_to_regi(FPU_REG const * r,u_char tag,int stnr)106 void FPU_copy_to_regi(FPU_REG const *r, u_char tag, int stnr)
107 {
108 reg_copy(r, &st(stnr));
109 FPU_settagi(stnr, tag);
110 }
111
FPU_copy_to_reg1(FPU_REG const * r,u_char tag)112 void FPU_copy_to_reg1(FPU_REG const *r, u_char tag)
113 {
114 reg_copy(r, &st(1));
115 FPU_settagi(1, tag);
116 }
117
FPU_copy_to_reg0(FPU_REG const * r,u_char tag)118 void FPU_copy_to_reg0(FPU_REG const *r, u_char tag)
119 {
120 int regnr = top;
121 regnr &= 7;
122
123 reg_copy(r, &st(0));
124
125 fpu_tag_word &= ~(3 << (regnr*2));
126 fpu_tag_word |= (tag & 3) << (regnr*2);
127 }
128