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Add conversion functions for i128

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This commit is contained in:
Christoffer Lerno
2022-10-20 19:30:42 +02:00
committed by Christoffer Lerno
parent d13b7ac96a
commit ae7aa65f35
2 changed files with 92 additions and 1 deletions
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92
lib/std/math_i128.c3
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@@ -239,3 +239,95 @@ fn double __floatuntidf(uint128 a) @extname("__floatuntidf") @weak
};
return bits.d;
}
fn uint128 __fixunsdfti(double a) @extname("__fixunsdfti") = fixuint(a);
fn uint128 __fixunssfti(float a) @extname("__fixunssfti") = fixuint(a);
fn int128 __fixdfti(double a) @extname("__fixdfti") = fixint(a);
fn int128 __fixsfti(float a) @extname("__fixsfti") = fixint(a);
private macro fixuint(a)
{
$switch ($typeof(a)):
$case double:
var $Rep = ulong;
const EXPONENT_BITS = 11;
const SIGNIFICANT_BITS = 52;
$case float:
var $Rep = uint;
const EXPONENT_BITS = 8;
const SIGNIFICANT_BITS = 23;
$case float16:
var $Rep = ushort;
const EXPONENT_BITS = 5;
const SIGNIFICANT_BITS = 10;
$case float128:
var $Rep = uint128;
const EXPONENT_BITS = 15;
const SIGNIFICANT_BITS = 112;
$endswitch;
const MAX_EXPONENT = 1 << EXPONENT_BITS - 1;
const EXPONENT_BIAS = MAX_EXPONENT >> 1;
const ONE_REP = (ulong)EXPONENT_BIAS << SIGNIFICANT_BITS;
const SIGN_BIT = ($Rep)1 << (EXPONENT_BITS + SIGNIFICANT_BITS);
const ABS_MASK = SIGN_BIT - 1;
const IMPLICIT_BIT = ($Rep)1 << SIGNIFICANT_BITS;
const SIGNIFICANT_MASK = IMPLICIT_BIT - 1;
const EXPONENT_MASK = ABS_MASK ^ SIGNIFICANT_MASK;
const QUIET_BIT = IMPLICIT_BIT >> 1;
const QNAN_REP = EXPONENT_MASK | QUIET_BIT;
const INF_REP = EXPONENT_MASK;
$Rep rep = bitcast(a, $Rep);
$Rep abs = rep & ABS_MASK;
int sign = rep & SIGN_BIT ? -1 : 1;
int exponent = (int)((abs >> SIGNIFICANT_BITS) - EXPONENT_BIAS);
$Rep significand = (abs & SIGNIFICANT_MASK) | IMPLICIT_BIT;
if (sign == -1 || exponent < 0) return 0u128;
if ((uint)exponent >= uint128.sizeof * 8) return ~0u128;
if (exponent < SIGNIFICANT_BITS) return (uint128)significand >> (SIGNIFICANT_BITS - exponent);
return (uint128)significand << (exponent - SIGNIFICANT_BITS);
}
private macro fixint(a)
{
$switch ($typeof(a)):
$case double:
var $Rep = ulong;
const EXPONENT_BITS = 11;
const SIGNIFICANT_BITS = 52;
$case float:
var $Rep = uint;
const EXPONENT_BITS = 8;
const SIGNIFICANT_BITS = 23;
$case float16:
var $Rep = ushort;
const EXPONENT_BITS = 5;
const SIGNIFICANT_BITS = 10;
$case float128:
var $Rep = uint128;
const EXPONENT_BITS = 15;
const SIGNIFICANT_BITS = 112;
$endswitch;
const MAX_EXPONENT = 1 << EXPONENT_BITS - 1;
const EXPONENT_BIAS = MAX_EXPONENT >> 1;
const ONE_REP = (ulong)EXPONENT_BIAS << SIGNIFICANT_BITS;
const SIGN_BIT = ($Rep)1 << (EXPONENT_BITS + SIGNIFICANT_BITS);
const ABS_MASK = SIGN_BIT - 1;
const IMPLICIT_BIT = ($Rep)1 << SIGNIFICANT_BITS;
const SIGNIFICANT_MASK = IMPLICIT_BIT - 1;
const EXPONENT_MASK = ABS_MASK ^ SIGNIFICANT_MASK;
const QUIET_BIT = IMPLICIT_BIT >> 1;
const QNAN_REP = EXPONENT_MASK | QUIET_BIT;
const INF_REP = EXPONENT_MASK;
$Rep rep = bitcast(a, $Rep);
$Rep abs = rep & ABS_MASK;
int sign = rep & SIGN_BIT ? -1 : 1;
int exponent = (int)((abs >> SIGNIFICANT_BITS) - EXPONENT_BIAS);
$Rep significand = (abs & SIGNIFICANT_MASK) | IMPLICIT_BIT;
if (exponent < 0) return 0;
if ((uint)exponent >= uint128.sizeof * 8) return sign == 1 ? int128.max : int128.min;
if (exponent < SIGNIFICANT_BITS) return sign * ((int128)significand >> (SIGNIFICANT_BITS - exponent));
return sign * ((int128)significand << (exponent - SIGNIFICANT_BITS));
}