Files
Odin/base/runtime/internal_i128.odin
2026-08-12 19:19:51 +02:00

263 lines
7.7 KiB
Odin

#+vet !cast
#+build !bedrock
package runtime
import "base:intrinsics"
@(private="file")
IS_WASM :: ODIN_ARCH == .wasm32 || ODIN_ARCH == .wasm64p32
@(link_name="__floattidf", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
floattidf :: proc "c" (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 := i32(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 & (i128(1) << DBL_MANT_DIG) != 0 {
a >>= 1
e += 1
}
} else {
a <<= u128(DBL_MANT_DIG - sd) & 127
}
fb: [2]u32
fb[1] = (u32(s) & 0x80000000) | // sign
(u32(e + 1023) << 20) | // exponent
u32((u64(a) >> 32) & 0x000FFFFF) // mantissa-high
fb[0] = u32(a) // mantissa-low
return transmute(f64)fb
}
@(link_name="__floattidf_unsigned", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
floattidf_unsigned :: proc "c" (a: u128) -> f64 {
DBL_MANT_DIG :: 53
if a == 0 {
return 0.0
}
a := a
N :: size_of(u128) * 8
sd: = N - intrinsics.count_leading_zeros(a) // number of significant digits
e := i32(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 = u128(u128(a) >> u128(sd - (DBL_MANT_DIG+2))) |
u128(u128(a) & (~u128(0) >> u128(N + DBL_MANT_DIG+2 - sd)) != 0)
}
a |= u128((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] = (0) | // sign
u32((e + 1023) << 20) | // exponent
u32((u64(a) >> 32) & 0x000FFFFF) // mantissa-high
fb[0] = u32(a) // mantissa-low
return transmute(f64)fb
}
// f64 -> unsigned integer conversion (truncating toward zero)
// decompose the f64 into significand and exponent, shift the significand into place,
// saturate out of range values
//
// Uses parts of compiler-rt's [fp_fixuint_impl.inc](https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/builtins/fp_fixuint_impl.inc), licensed under the [Apache License v2.0 with LLVM Exceptions](https://github.com/llvm/llvm-project/blob/main/compiler-rt/LICENSE.TXT).
// For a copy of the license, see `LICENSE-compiler-rt.txt`.
@(private="file")
fixuint :: proc "contextless" ($U: typeid, a: f64) -> U where intrinsics.type_is_unsigned(U) {
BITS :: 8 * size_of(U)
SIGNIFICAND_BITS :: 52
EXPONENT_BIAS :: 1023
IMPLICIT_BIT :: (u64(1) << SIGNIFICAND_BITS)
SIGNIFICAND_MASK :: (IMPLICIT_BIT - 1)
// Break a into sign, exponent, significand parts.
a_rep := transmute(u64)a
negative := (a_rep >> 63) != 0
exponent := i32((a_rep >> SIGNIFICAND_BITS) & 0x7ff) - EXPONENT_BIAS
significand := (a_rep & SIGNIFICAND_MASK) | IMPLICIT_BIT
// If either the value or the exponent is negative, the result is zero.
if negative || exponent < 0 {
return 0
}
// If the value is too large for the integer type, saturate.
if exponent >= BITS {
return max(U)
}
// If 0 <= exponent < SIGNIFICAND_BITS, right shift to get the result.
// Otherwise, shift left.
if exponent < SIGNIFICAND_BITS {
return U(significand >> u32(SIGNIFICAND_BITS - exponent))
}
return U(significand) << u32(exponent - SIGNIFICAND_BITS)
}
// f64 -> signed integer conversion (truncating toward zero)
// decompose the f64 into significand and exponent, shift the significand into place,
// saturate out of range values
//
// Uses parts of compiler-rt's [fp_fixuint_impl.inc](https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/builtins/fp_fixuint_impl.inc), licensed under the [Apache License v2.0 with LLVM Exceptions](https://github.com/llvm/llvm-project/blob/main/compiler-rt/LICENSE.TXT).
// For a copy of the license, see `LICENSE-compiler-rt.txt`.
@(private="file")
fixint :: proc "contextless" ($T: typeid, a: f64) -> T where intrinsics.type_is_integer(T), !intrinsics.type_is_unsigned(T) {
BITS :: 8 * size_of(T)
SIGNIFICAND_BITS :: 52
EXPONENT_BIAS :: 1023
IMPLICIT_BIT :: (u64(1) << SIGNIFICAND_BITS)
SIGNIFICAND_MASK :: (IMPLICIT_BIT - 1)
// Break a into sign, exponent, significand parts.
a_rep := transmute(u64)a
negative := (a_rep >> 63) != 0
exponent := i32((a_rep >> SIGNIFICAND_BITS) & 0x7ff) - EXPONENT_BIAS
significand := (a_rep & SIGNIFICAND_MASK) | IMPLICIT_BIT
// If exponent is negative, the result is zero.
if exponent < 0 {
return 0
}
// If the value is too large for the integer type, saturate;
// (the only exactly representable value with exponent BITS-1 is min(T))
// this deviates from clang/compiler-rt (it instead wraps from BITS-1 to BITS,
// that is, f64(1 << 127) would wrap to min(i128) (for T=i128)),
// while this saturates consistently
if exponent >= BITS - 1 {
return min(T) if negative else max(T)
}
// If 0 <= exponent < SIGNIFICAND_BITS, right shift to get the result.
// Otherwise, shift left. After saturation the magnitude is below
// 1 << (BITS-1), so it fits in T and negation can't overflow
r: T
if exponent < SIGNIFICAND_BITS {
r = T(significand >> u32(SIGNIFICAND_BITS - exponent))
} else {
r = T(significand) << u32(exponent - SIGNIFICAND_BITS)
}
return -r if negative else r
}
@(link_name="__fixunsdfti", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
fixunsdfti :: proc "c" (a: f64) -> u128 {
return fixuint(u128, a)
}
@(link_name="__fixunsdfdi", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
fixunsdfdi :: proc "c" (a: f64) -> u64 {
return fixuint(u64, a)
}
@(link_name="__fixdfti", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
fixdfti :: proc "c" (a: f64) -> i128 {
return fixint(i128, a)
}
@(link_name="__fixdfdi", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
fixdfdi :: proc "c" (a: f64) -> i64 {
return fixint(i64, a)
}
@(link_name="__umodti3", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
umodti3 :: proc "c" (a, b: u128) -> u128 {
r: u128 = ---
_ = udivmod128(a, b, &r)
return r
}
@(link_name="__udivmodti4", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
udivmodti4 :: proc "c" (a, b: u128, rem: ^u128) -> u128 {
return udivmod128(a, b, rem)
}
when !IS_WASM {
@(link_name="__udivti3", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
udivti3 :: proc "c" (a, b: u128) -> u128 {
return udivmodti4(a, b, nil)
}
}
@(link_name="__modti3", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
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(u128(an), u128(bn), &r)
return (i128(r) ~ s_a) - s_a
}
@(link_name="__divmodti4", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
divmodti4 :: proc "c" (a, b: i128, rem: ^i128) -> i128 {
s_a := a >> (128 - 1) // -1 if negative or 0
s_b := b >> (128 - 1)
an := (a ~ s_a) - s_a // absolute
bn := (b ~ s_b) - s_b
s_b ~= s_a // quotient sign
u_s_b := u128(s_b)
u_s_a := u128(s_a)
r: u128 = ---
u := i128((udivmodti4(u128(an), u128(bn), &r) ~ u_s_b) - u_s_b) // negate if negative
rem^ = i128((r ~ u_s_a) - u_s_a)
return u
}
@(link_name="__divti3", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE)
divti3 :: proc "c" (a, b: i128) -> i128 {
s_a := a >> (128 - 1) // -1 if negative or 0
s_b := b >> (128 - 1)
an := (a ~ s_a) - s_a // absolute
bn := (b ~ s_b) - s_b
s_a ~= s_b // quotient sign
u_s_a := u128(s_a)
return i128((udivmodti4(u128(an), u128(bn), nil) ~ u_s_a) - u_s_a) // negate if negative
}