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-rw-r--r--arch/i386/math-emu/reg_constant.c120
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diff --git a/arch/i386/math-emu/reg_constant.c b/arch/i386/math-emu/reg_constant.c
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1/*---------------------------------------------------------------------------+
2 | reg_constant.c |
3 | |
4 | All of the constant FPU_REGs |
5 | |
6 | Copyright (C) 1992,1993,1994,1997 |
7 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
8 | Australia. E-mail billm@suburbia.net |
9 | |
10 | |
11 +---------------------------------------------------------------------------*/
12
13#include "fpu_system.h"
14#include "fpu_emu.h"
15#include "status_w.h"
16#include "reg_constant.h"
17#include "control_w.h"
18
19
20#define MAKE_REG(s,e,l,h) { l, h, \
21 ((EXTENDED_Ebias+(e)) | ((SIGN_##s != 0)*0x8000)) }
22
23FPU_REG const CONST_1 = MAKE_REG(POS, 0, 0x00000000, 0x80000000);
24#if 0
25FPU_REG const CONST_2 = MAKE_REG(POS, 1, 0x00000000, 0x80000000);
26FPU_REG const CONST_HALF = MAKE_REG(POS, -1, 0x00000000, 0x80000000);
27#endif /* 0 */
28static FPU_REG const CONST_L2T = MAKE_REG(POS, 1, 0xcd1b8afe, 0xd49a784b);
29static FPU_REG const CONST_L2E = MAKE_REG(POS, 0, 0x5c17f0bc, 0xb8aa3b29);
30FPU_REG const CONST_PI = MAKE_REG(POS, 1, 0x2168c235, 0xc90fdaa2);
31FPU_REG const CONST_PI2 = MAKE_REG(POS, 0, 0x2168c235, 0xc90fdaa2);
32FPU_REG const CONST_PI4 = MAKE_REG(POS, -1, 0x2168c235, 0xc90fdaa2);
33static FPU_REG const CONST_LG2 = MAKE_REG(POS, -2, 0xfbcff799, 0x9a209a84);
34static FPU_REG const CONST_LN2 = MAKE_REG(POS, -1, 0xd1cf79ac, 0xb17217f7);
35
36/* Extra bits to take pi/2 to more than 128 bits precision. */
37FPU_REG const CONST_PI2extra = MAKE_REG(NEG, -66,
38 0xfc8f8cbb, 0xece675d1);
39
40/* Only the sign (and tag) is used in internal zeroes */
41FPU_REG const CONST_Z = MAKE_REG(POS, EXP_UNDER, 0x0, 0x0);
42
43/* Only the sign and significand (and tag) are used in internal NaNs */
44/* The 80486 never generates one of these
45FPU_REG const CONST_SNAN = MAKE_REG(POS, EXP_OVER, 0x00000001, 0x80000000);
46 */
47/* This is the real indefinite QNaN */
48FPU_REG const CONST_QNaN = MAKE_REG(NEG, EXP_OVER, 0x00000000, 0xC0000000);
49
50/* Only the sign (and tag) is used in internal infinities */
51FPU_REG const CONST_INF = MAKE_REG(POS, EXP_OVER, 0x00000000, 0x80000000);
52
53
54static void fld_const(FPU_REG const *c, int adj, u_char tag)
55{
56 FPU_REG *st_new_ptr;
57
58 if ( STACK_OVERFLOW )
59 {
60 FPU_stack_overflow();
61 return;
62 }
63 push();
64 reg_copy(c, st_new_ptr);
65 st_new_ptr->sigl += adj; /* For all our fldxxx constants, we don't need to
66 borrow or carry. */
67 FPU_settag0(tag);
68 clear_C1();
69}
70
71/* A fast way to find out whether x is one of RC_DOWN or RC_CHOP
72 (and not one of RC_RND or RC_UP).
73 */
74#define DOWN_OR_CHOP(x) (x & RC_DOWN)
75
76static void fld1(int rc)
77{
78 fld_const(&CONST_1, 0, TAG_Valid);
79}
80
81static void fldl2t(int rc)
82{
83 fld_const(&CONST_L2T, (rc == RC_UP) ? 1 : 0, TAG_Valid);
84}
85
86static void fldl2e(int rc)
87{
88 fld_const(&CONST_L2E, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
89}
90
91static void fldpi(int rc)
92{
93 fld_const(&CONST_PI, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
94}
95
96static void fldlg2(int rc)
97{
98 fld_const(&CONST_LG2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
99}
100
101static void fldln2(int rc)
102{
103 fld_const(&CONST_LN2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
104}
105
106static void fldz(int rc)
107{
108 fld_const(&CONST_Z, 0, TAG_Zero);
109}
110
111typedef void (*FUNC_RC)(int);
112
113static FUNC_RC constants_table[] = {
114 fld1, fldl2t, fldl2e, fldpi, fldlg2, fldln2, fldz, (FUNC_RC)FPU_illegal
115};
116
117void fconst(void)
118{
119 (constants_table[FPU_rm])(control_word & CW_RC);
120}