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-rw-r--r--arch/x86/math-emu/poly_2xm1.c199
1 files changed, 94 insertions, 105 deletions
diff --git a/arch/x86/math-emu/poly_2xm1.c b/arch/x86/math-emu/poly_2xm1.c
index 9766ad5e9743..d8f2be3c8383 100644
--- a/arch/x86/math-emu/poly_2xm1.c
+++ b/arch/x86/math-emu/poly_2xm1.c
@@ -17,21 +17,19 @@
17#include "control_w.h" 17#include "control_w.h"
18#include "poly.h" 18#include "poly.h"
19 19
20
21#define HIPOWER 11 20#define HIPOWER 11
22static const unsigned long long lterms[HIPOWER] = 21static const unsigned long long lterms[HIPOWER] = {
23{ 22 0x0000000000000000LL, /* This term done separately as 12 bytes */
24 0x0000000000000000LL, /* This term done separately as 12 bytes */ 23 0xf5fdeffc162c7543LL,
25 0xf5fdeffc162c7543LL, 24 0x1c6b08d704a0bfa6LL,
26 0x1c6b08d704a0bfa6LL, 25 0x0276556df749cc21LL,
27 0x0276556df749cc21LL, 26 0x002bb0ffcf14f6b8LL,
28 0x002bb0ffcf14f6b8LL, 27 0x0002861225ef751cLL,
29 0x0002861225ef751cLL, 28 0x00001ffcbfcd5422LL,
30 0x00001ffcbfcd5422LL, 29 0x00000162c005d5f1LL,
31 0x00000162c005d5f1LL, 30 0x0000000da96ccb1bLL,
32 0x0000000da96ccb1bLL, 31 0x0000000078d1b897LL,
33 0x0000000078d1b897LL, 32 0x000000000422b029LL
34 0x000000000422b029LL
35}; 33};
36 34
37static const Xsig hiterm = MK_XSIG(0xb17217f7, 0xd1cf79ab, 0xc8a39194); 35static const Xsig hiterm = MK_XSIG(0xb17217f7, 0xd1cf79ab, 0xc8a39194);
@@ -45,112 +43,103 @@ static const Xsig shiftterm2 = MK_XSIG(0xb504f333, 0xf9de6484, 0x597d89b3);
45static const Xsig shiftterm3 = MK_XSIG(0xd744fcca, 0xd69d6af4, 0x39a68bb9); 43static const Xsig shiftterm3 = MK_XSIG(0xd744fcca, 0xd69d6af4, 0x39a68bb9);
46 44
47static const Xsig *shiftterm[] = { &shiftterm0, &shiftterm1, 45static const Xsig *shiftterm[] = { &shiftterm0, &shiftterm1,
48 &shiftterm2, &shiftterm3 }; 46 &shiftterm2, &shiftterm3
49 47};
50 48
51/*--- poly_2xm1() -----------------------------------------------------------+ 49/*--- poly_2xm1() -----------------------------------------------------------+
52 | Requires st(0) which is TAG_Valid and < 1. | 50 | Requires st(0) which is TAG_Valid and < 1. |
53 +---------------------------------------------------------------------------*/ 51 +---------------------------------------------------------------------------*/
54int poly_2xm1(u_char sign, FPU_REG *arg, FPU_REG *result) 52int poly_2xm1(u_char sign, FPU_REG * arg, FPU_REG * result)
55{ 53{
56 long int exponent, shift; 54 long int exponent, shift;
57 unsigned long long Xll; 55 unsigned long long Xll;
58 Xsig accumulator, Denom, argSignif; 56 Xsig accumulator, Denom, argSignif;
59 u_char tag; 57 u_char tag;
60 58
61 exponent = exponent16(arg); 59 exponent = exponent16(arg);
62 60
63#ifdef PARANOID 61#ifdef PARANOID
64 if ( exponent >= 0 ) /* Don't want a |number| >= 1.0 */ 62 if (exponent >= 0) { /* Don't want a |number| >= 1.0 */
65 { 63 /* Number negative, too large, or not Valid. */
66 /* Number negative, too large, or not Valid. */ 64 EXCEPTION(EX_INTERNAL | 0x127);
67 EXCEPTION(EX_INTERNAL|0x127); 65 return 1;
68 return 1; 66 }
69 }
70#endif /* PARANOID */ 67#endif /* PARANOID */
71 68
72 argSignif.lsw = 0; 69 argSignif.lsw = 0;
73 XSIG_LL(argSignif) = Xll = significand(arg); 70 XSIG_LL(argSignif) = Xll = significand(arg);
74 71
75 if ( exponent == -1 ) 72 if (exponent == -1) {
76 { 73 shift = (argSignif.msw & 0x40000000) ? 3 : 2;
77 shift = (argSignif.msw & 0x40000000) ? 3 : 2; 74 /* subtract 0.5 or 0.75 */
78 /* subtract 0.5 or 0.75 */ 75 exponent -= 2;
79 exponent -= 2; 76 XSIG_LL(argSignif) <<= 2;
80 XSIG_LL(argSignif) <<= 2; 77 Xll <<= 2;
81 Xll <<= 2; 78 } else if (exponent == -2) {
82 } 79 shift = 1;
83 else if ( exponent == -2 ) 80 /* subtract 0.25 */
84 { 81 exponent--;
85 shift = 1; 82 XSIG_LL(argSignif) <<= 1;
86 /* subtract 0.25 */ 83 Xll <<= 1;
87 exponent--; 84 } else
88 XSIG_LL(argSignif) <<= 1; 85 shift = 0;
89 Xll <<= 1; 86
90 } 87 if (exponent < -2) {
91 else 88 /* Shift the argument right by the required places. */
92 shift = 0; 89 if (FPU_shrx(&Xll, -2 - exponent) >= 0x80000000U)
93 90 Xll++; /* round up */
94 if ( exponent < -2 ) 91 }
95 { 92
96 /* Shift the argument right by the required places. */ 93 accumulator.lsw = accumulator.midw = accumulator.msw = 0;
97 if ( FPU_shrx(&Xll, -2-exponent) >= 0x80000000U ) 94 polynomial_Xsig(&accumulator, &Xll, lterms, HIPOWER - 1);
98 Xll++; /* round up */ 95 mul_Xsig_Xsig(&accumulator, &argSignif);
99 } 96 shr_Xsig(&accumulator, 3);
100 97
101 accumulator.lsw = accumulator.midw = accumulator.msw = 0; 98 mul_Xsig_Xsig(&argSignif, &hiterm); /* The leading term */
102 polynomial_Xsig(&accumulator, &Xll, lterms, HIPOWER-1); 99 add_two_Xsig(&accumulator, &argSignif, &exponent);
103 mul_Xsig_Xsig(&accumulator, &argSignif); 100
104 shr_Xsig(&accumulator, 3); 101 if (shift) {
105 102 /* The argument is large, use the identity:
106 mul_Xsig_Xsig(&argSignif, &hiterm); /* The leading term */ 103 f(x+a) = f(a) * (f(x) + 1) - 1;
107 add_two_Xsig(&accumulator, &argSignif, &exponent); 104 */
108 105 shr_Xsig(&accumulator, -exponent);
109 if ( shift ) 106 accumulator.msw |= 0x80000000; /* add 1.0 */
110 { 107 mul_Xsig_Xsig(&accumulator, shiftterm[shift]);
111 /* The argument is large, use the identity: 108 accumulator.msw &= 0x3fffffff; /* subtract 1.0 */
112 f(x+a) = f(a) * (f(x) + 1) - 1; 109 exponent = 1;
113 */ 110 }
114 shr_Xsig(&accumulator, - exponent); 111
115 accumulator.msw |= 0x80000000; /* add 1.0 */ 112 if (sign != SIGN_POS) {
116 mul_Xsig_Xsig(&accumulator, shiftterm[shift]); 113 /* The argument is negative, use the identity:
117 accumulator.msw &= 0x3fffffff; /* subtract 1.0 */ 114 f(-x) = -f(x) / (1 + f(x))
118 exponent = 1; 115 */
119 } 116 Denom.lsw = accumulator.lsw;
120 117 XSIG_LL(Denom) = XSIG_LL(accumulator);
121 if ( sign != SIGN_POS ) 118 if (exponent < 0)
122 { 119 shr_Xsig(&Denom, -exponent);
123 /* The argument is negative, use the identity: 120 else if (exponent > 0) {
124 f(-x) = -f(x) / (1 + f(x)) 121 /* exponent must be 1 here */
125 */ 122 XSIG_LL(Denom) <<= 1;
126 Denom.lsw = accumulator.lsw; 123 if (Denom.lsw & 0x80000000)
127 XSIG_LL(Denom) = XSIG_LL(accumulator); 124 XSIG_LL(Denom) |= 1;
128 if ( exponent < 0 ) 125 (Denom.lsw) <<= 1;
129 shr_Xsig(&Denom, - exponent); 126 }
130 else if ( exponent > 0 ) 127 Denom.msw |= 0x80000000; /* add 1.0 */
131 { 128 div_Xsig(&accumulator, &Denom, &accumulator);
132 /* exponent must be 1 here */
133 XSIG_LL(Denom) <<= 1;
134 if ( Denom.lsw & 0x80000000 )
135 XSIG_LL(Denom) |= 1;
136 (Denom.lsw) <<= 1;
137 } 129 }
138 Denom.msw |= 0x80000000; /* add 1.0 */
139 div_Xsig(&accumulator, &Denom, &accumulator);
140 }
141 130
142 /* Convert to 64 bit signed-compatible */ 131 /* Convert to 64 bit signed-compatible */
143 exponent += round_Xsig(&accumulator); 132 exponent += round_Xsig(&accumulator);
144 133
145 result = &st(0); 134 result = &st(0);
146 significand(result) = XSIG_LL(accumulator); 135 significand(result) = XSIG_LL(accumulator);
147 setexponent16(result, exponent); 136 setexponent16(result, exponent);
148 137
149 tag = FPU_round(result, 1, 0, FULL_PRECISION, sign); 138 tag = FPU_round(result, 1, 0, FULL_PRECISION, sign);
150 139
151 setsign(result, sign); 140 setsign(result, sign);
152 FPU_settag0(tag); 141 FPU_settag0(tag);
153 142
154 return 0; 143 return 0;
155 144
156} 145}
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