1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
package runtime
import "intrinsics"
@(link_name="__umodti3")
umodti3 :: proc "c" (a, b: u128) -> u128 {
r: u128 = ---;
_ = udivmod128(a, b, &r);
return r;
}
@(link_name="__udivmodti4")
udivmodti4 :: proc "c" (a, b: u128, rem: ^u128) -> u128 {
return udivmod128(a, b, rem);
}
@(link_name="__udivti3")
udivti3 :: proc "c" (a, b: u128) -> u128 {
return udivmodti4(a, b, nil);
}
@(link_name="__modti3")
modti3 :: proc "c" (a, b: i128) -> i128 {
s_a := a >> (128 - 1);
s_b := b >> (128 - 1);
an := (a ~ s_a) - s_a;
bn := (b ~ s_b) - s_b;
r: u128 = ---;
_ = udivmod128(transmute(u128)an, transmute(u128)bn, &r);
return (transmute(i128)r ~ s_a) - s_a;
}
@(link_name="__divmodti4")
divmodti4 :: proc "c" (a, b: i128, rem: ^i128) -> i128 {
u := udivmod128(transmute(u128)a, transmute(u128)b, cast(^u128)rem);
return transmute(i128)u;
}
@(link_name="__divti3")
divti3 :: proc "c" (a, b: i128) -> i128 {
u := udivmodti4(transmute(u128)a, transmute(u128)b, nil);
return transmute(i128)u;
}
@(link_name="__fixdfti")
fixdfti :: proc(a: u64) -> i128 {
significandBits :: 52;
typeWidth :: (size_of(u64)*8);
exponentBits :: (typeWidth - significandBits - 1);
maxExponent :: ((1 << exponentBits) - 1);
exponentBias :: (maxExponent >> 1);
implicitBit :: (u64(1) << significandBits);
significandMask :: (implicitBit - 1);
signBit :: (u64(1) << (significandBits + exponentBits));
absMask :: (signBit - 1);
exponentMask :: (absMask ~ significandMask);
// Break a into sign, exponent, significand
aRep := a;
aAbs := aRep & absMask;
sign := i128(-1 if aRep & signBit != 0 else 1);
exponent := u64((aAbs >> significandBits) - exponentBias);
significand := u64((aAbs & significandMask) | implicitBit);
// If exponent is negative, the result is zero.
if exponent < 0 {
return 0;
}
// If the value is too large for the integer type, saturate.
if exponent >= size_of(i128) * 8 {
return max(i128) if sign == 1 else min(i128);
}
// If 0 <= exponent < significandBits, right shift to get the result.
// Otherwise, shift left.
if exponent < significandBits {
return sign * i128(significand >> (significandBits - exponent));
} else {
return sign * (i128(significand) << (exponent - significandBits));
}
}
@(link_name="__floattidf")
floattidf :: proc(a: i128) -> f64 {
DBL_MANT_DIG :: 53;
if a == 0 {
return 0.0;
}
a := a;
N :: size_of(i128) * 8;
s := a >> (N-1);
a = (a ~ s) - s;
sd: = N - intrinsics.count_leading_zeros(a); // number of significant digits
e := u32(sd - 1); // exponent
if sd > DBL_MANT_DIG {
switch sd {
case DBL_MANT_DIG + 1:
a <<= 1;
case DBL_MANT_DIG + 2:
// okay
case:
a = i128(u128(a) >> u128(sd - (DBL_MANT_DIG+2))) |
i128(u128(a) & (~u128(0) >> u128(N + DBL_MANT_DIG+2 - sd)) != 0);
};
a |= i128((a & 4) != 0);
a += 1;
a >>= 2;
if a & (1 << DBL_MANT_DIG) != 0 {
a >>= 1;
e += 1;
}
} else {
a <<= u128(DBL_MANT_DIG - sd);
}
fb: [2]u32;
fb[1] = (u32(s) & 0x80000000) | // sign
((e + 1023) << 20) | // exponent
u32((u64(a) >> 32) & 0x000FFFFF); // mantissa-high
fb[1] = u32(a); // mantissa-low
return transmute(f64)fb;
}
|
