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1da177e4 LT |
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 | ||
1da177e4 LT |
19 | #define MAKE_REG(s,e,l,h) { l, h, \ |
20 | ((EXTENDED_Ebias+(e)) | ((SIGN_##s != 0)*0x8000)) } | |
21 | ||
3d0d14f9 | 22 | FPU_REG const CONST_1 = MAKE_REG(POS, 0, 0x00000000, 0x80000000); |
1da177e4 | 23 | #if 0 |
3d0d14f9 | 24 | FPU_REG const CONST_2 = MAKE_REG(POS, 1, 0x00000000, 0x80000000); |
1da177e4 | 25 | FPU_REG const CONST_HALF = MAKE_REG(POS, -1, 0x00000000, 0x80000000); |
3d0d14f9 IM |
26 | #endif /* 0 */ |
27 | static FPU_REG const CONST_L2T = MAKE_REG(POS, 1, 0xcd1b8afe, 0xd49a784b); | |
28 | static FPU_REG const CONST_L2E = MAKE_REG(POS, 0, 0x5c17f0bc, 0xb8aa3b29); | |
29 | FPU_REG const CONST_PI = MAKE_REG(POS, 1, 0x2168c235, 0xc90fdaa2); | |
30 | FPU_REG const CONST_PI2 = MAKE_REG(POS, 0, 0x2168c235, 0xc90fdaa2); | |
31 | FPU_REG const CONST_PI4 = MAKE_REG(POS, -1, 0x2168c235, 0xc90fdaa2); | |
32 | static FPU_REG const CONST_LG2 = MAKE_REG(POS, -2, 0xfbcff799, 0x9a209a84); | |
33 | static FPU_REG const CONST_LN2 = MAKE_REG(POS, -1, 0xd1cf79ac, 0xb17217f7); | |
1da177e4 LT |
34 | |
35 | /* Extra bits to take pi/2 to more than 128 bits precision. */ | |
36 | FPU_REG const CONST_PI2extra = MAKE_REG(NEG, -66, | |
3d0d14f9 | 37 | 0xfc8f8cbb, 0xece675d1); |
1da177e4 LT |
38 | |
39 | /* Only the sign (and tag) is used in internal zeroes */ | |
3d0d14f9 | 40 | FPU_REG const CONST_Z = MAKE_REG(POS, EXP_UNDER, 0x0, 0x0); |
1da177e4 LT |
41 | |
42 | /* Only the sign and significand (and tag) are used in internal NaNs */ | |
43 | /* The 80486 never generates one of these | |
44 | FPU_REG const CONST_SNAN = MAKE_REG(POS, EXP_OVER, 0x00000001, 0x80000000); | |
45 | */ | |
46 | /* This is the real indefinite QNaN */ | |
47 | FPU_REG const CONST_QNaN = MAKE_REG(NEG, EXP_OVER, 0x00000000, 0xC0000000); | |
48 | ||
49 | /* Only the sign (and tag) is used in internal infinities */ | |
3d0d14f9 | 50 | FPU_REG const CONST_INF = MAKE_REG(POS, EXP_OVER, 0x00000000, 0x80000000); |
1da177e4 LT |
51 | |
52 | static void fld_const(FPU_REG const *c, int adj, u_char tag) | |
53 | { | |
3d0d14f9 IM |
54 | FPU_REG *st_new_ptr; |
55 | ||
56 | if (STACK_OVERFLOW) { | |
57 | FPU_stack_overflow(); | |
58 | return; | |
59 | } | |
60 | push(); | |
61 | reg_copy(c, st_new_ptr); | |
62 | st_new_ptr->sigl += adj; /* For all our fldxxx constants, we don't need to | |
63 | borrow or carry. */ | |
64 | FPU_settag0(tag); | |
65 | clear_C1(); | |
1da177e4 LT |
66 | } |
67 | ||
68 | /* A fast way to find out whether x is one of RC_DOWN or RC_CHOP | |
69 | (and not one of RC_RND or RC_UP). | |
70 | */ | |
71 | #define DOWN_OR_CHOP(x) (x & RC_DOWN) | |
72 | ||
73 | static void fld1(int rc) | |
74 | { | |
3d0d14f9 | 75 | fld_const(&CONST_1, 0, TAG_Valid); |
1da177e4 LT |
76 | } |
77 | ||
78 | static void fldl2t(int rc) | |
79 | { | |
3d0d14f9 | 80 | fld_const(&CONST_L2T, (rc == RC_UP) ? 1 : 0, TAG_Valid); |
1da177e4 LT |
81 | } |
82 | ||
83 | static void fldl2e(int rc) | |
84 | { | |
3d0d14f9 | 85 | fld_const(&CONST_L2E, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
1da177e4 LT |
86 | } |
87 | ||
88 | static void fldpi(int rc) | |
89 | { | |
3d0d14f9 | 90 | fld_const(&CONST_PI, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
1da177e4 LT |
91 | } |
92 | ||
93 | static void fldlg2(int rc) | |
94 | { | |
3d0d14f9 | 95 | fld_const(&CONST_LG2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
1da177e4 LT |
96 | } |
97 | ||
98 | static void fldln2(int rc) | |
99 | { | |
3d0d14f9 | 100 | fld_const(&CONST_LN2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
1da177e4 LT |
101 | } |
102 | ||
103 | static void fldz(int rc) | |
104 | { | |
3d0d14f9 | 105 | fld_const(&CONST_Z, 0, TAG_Zero); |
1da177e4 LT |
106 | } |
107 | ||
3d0d14f9 | 108 | typedef void (*FUNC_RC) (int); |
1da177e4 LT |
109 | |
110 | static FUNC_RC constants_table[] = { | |
3d0d14f9 | 111 | fld1, fldl2t, fldl2e, fldpi, fldlg2, fldln2, fldz, (FUNC_RC) FPU_illegal |
1da177e4 LT |
112 | }; |
113 | ||
114 | void fconst(void) | |
115 | { | |
3d0d14f9 | 116 | (constants_table[FPU_rm]) (control_word & CW_RC); |
1da177e4 | 117 | } |