diff --git a/base/runtime/internal_i128.odin b/base/runtime/internal_i128.odin index f4a0f90ed..df5066843 100644 --- a/base/runtime/internal_i128.odin +++ b/base/runtime/internal_i128.odin @@ -91,22 +91,107 @@ floattidf_unsigned :: proc "c" (a: u128) -> f64 { } +// f64 -> unsigned integer conversion (truncating toward zero) +// port of clang/compiler-rt's fp_fixuint_impl.inc; +// decompose the f64 into significand and exponent, shift the significand into place, +// saturate out of range values +@(private="file") +fixuint :: proc "contextless" ($U: typeid, a: f64) -> U where intrinsics.type_is_unsigned(U) { + BITS :: 8 * size_of(U) + SIGNIFICAND_BITS :: 52 + EXPONENT_BIAS :: 1023 + + IMPLICIT_BIT :: (u64(1) << SIGNIFICAND_BITS) + SIGNIFICAND_MASK :: (IMPLICIT_BIT - 1) + + // Break a into sign, exponent, significand parts. + a_rep := transmute(u64)a + negative := (a_rep >> 63) != 0 + exponent := i32((a_rep >> SIGNIFICAND_BITS) & 0x7ff) - EXPONENT_BIAS + significand := (a_rep & SIGNIFICAND_MASK) | IMPLICIT_BIT + + // If either the value or the exponent is negative, the result is zero. + if negative || exponent < 0 { + return 0 + } + + // If the value is too large for the integer type, saturate. + if exponent >= BITS { + return max(U) + } + + // If 0 <= exponent < SIGNIFICAND_BITS, right shift to get the result. + // Otherwise, shift left. + if exponent < SIGNIFICAND_BITS { + return U(significand >> u32(SIGNIFICAND_BITS - exponent)) + } + return U(significand) << u32(exponent - SIGNIFICAND_BITS) +} + +// f64 -> signed integer conversion (truncating toward zero) +// port of clang/compiler-rt's fp_fixint_impl.inc; +// decompose the f64 into significand and exponent, shift the significand into place, +// saturate out of range values +@(private="file") +fixint :: proc "contextless" ($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 :: #force_no_inline proc "c" (a: f64) -> u128 { - // TODO(bill): implement `fixunsdfti` correctly - x := u64(a) - return u128(x) +fixunsdfti :: proc "c" (a: f64) -> u128 { + return fixuint(u128, a) } @(link_name="__fixunsdfdi", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE) -fixunsdfdi :: #force_no_inline proc "c" (a: f64) -> i128 { - // TODO(bill): implement `fixunsdfdi` correctly - x := i64(a) - return i128(x) +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) @@ -173,45 +258,3 @@ divti3 :: proc "c" (a, b: i128) -> i128 { return i128((udivmodti4(u128(an), u128(bn), nil) ~ u_s_a) - u_s_a) // negate if negative } - -@(link_name="__fixdfti", linkage=RUNTIME_LINKAGE, require=RUNTIME_REQUIRE) -fixdfti :: proc "c" (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)) - } - -} - diff --git a/src/check_expr.cpp b/src/check_expr.cpp index 81936119b..ec276884a 100644 --- a/src/check_expr.cpp +++ b/src/check_expr.cpp @@ -3982,7 +3982,7 @@ gb_internal void check_cast(CheckerContext *c, Operand *x, Type *type, bool forb add_package_dependency(c, "runtime", "floattidf", REQUIRE); } else if (is_type_integer_128bit(dst) && is_type_float(src)) { add_package_dependency(c, "runtime", "fixunsdfti", REQUIRE); - add_package_dependency(c, "runtime", "fixunsdfdi", REQUIRE); + add_package_dependency(c, "runtime", "fixdfti", REQUIRE); } else if (src == t_f16 && is_type_float(dst)) { add_package_dependency(c, "runtime", "gnu_h2f_ieee", REQUIRE); add_package_dependency(c, "runtime", "extendhfsf2", REQUIRE); diff --git a/src/llvm_backend_expr.cpp b/src/llvm_backend_expr.cpp index 63c45711f..128b688ce 100644 --- a/src/llvm_backend_expr.cpp +++ b/src/llvm_backend_expr.cpp @@ -2538,8 +2538,8 @@ gb_internal lbValue lb_emit_conv(lbProcedure *p, lbValue value, Type *t) { TEMPORARY_ALLOCATOR_GUARD(); auto args = array_make(temporary_allocator(), 1); - args[0] = value; - char const *call = "fixunsdfdi"; + args[0] = lb_emit_conv(p, value, t_f64); + char const *call = "fixdfti"; if (is_type_unsigned(dst)) { call = "fixunsdfti"; } diff --git a/tests/internal/test_128_float_conversion.odin b/tests/internal/test_128_float_conversion.odin new file mode 100644 index 000000000..6d82dd817 --- /dev/null +++ b/tests/internal/test_128_float_conversion.odin @@ -0,0 +1,48 @@ +package test_internal + +import "core:testing" + +// #force_no_inline so conversions are not folded; +// they must go through the runtime __fixunsdfti/__fixdfti +@(private="file") f64_to_u128 :: #force_no_inline proc(f: f64) -> u128 { return u128(f) } +@(private="file") f64_to_i128 :: #force_no_inline proc(f: f64) -> i128 { return i128(f) } +@(private="file") f32_to_u128 :: #force_no_inline proc(f: f32) -> u128 { return u128(f) } +@(private="file") f32_to_i128 :: #force_no_inline proc(f: f32) -> i128 { return i128(f) } + +@test +test_f64_to_u128 :: proc(t: ^testing.T) { + testing.expect_value(t, f64_to_u128(2.75), 2) // trunc toward 0 + testing.expect_value(t, f64_to_u128(0.75), 0) // < 1 + testing.expect_value(t, f64_to_u128(-3.5), 0) // negative to 0 + testing.expect_value(t, f64_to_u128(f64(1 << 51)), u128(1) << 51) // significand shifts right + testing.expect_value(t, f64_to_u128(f64(1 << 52)), u128(1) << 52) // no shift + testing.expect_value(t, f64_to_u128(f64(1 << 53)), u128(1) << 53) // significand shifts left + testing.expect_value(t, f64_to_u128(1e19), 10_000_000_000_000_000_000) + testing.expect_value(t, f64_to_u128(f64(1 << 80)), u128(1) << 80) // > max(u64) + testing.expect_value(t, f64_to_u128(2 * f64(1 << 127)), max(u128)) // out of range saturates, implementation specific +} + +@test +test_f64_to_i128 :: proc(t: ^testing.T) { + testing.expect_value(t, f64_to_i128(-2.75), -2) // trunc toward 0 + testing.expect_value(t, f64_to_i128(-0.75), 0) // |f| < 1 + testing.expect_value(t, f64_to_i128(1e19), 10_000_000_000_000_000_000) // > max(i64) + testing.expect_value(t, f64_to_i128(f64(-(1 << 80))), -(i128(1) << 80)) + testing.expect_value(t, f64_to_i128(f64(1 << 126)), i128(1) << 126) + testing.expect_value(t, f64_to_i128(f64(min(i128))), min(i128)) // exact + // out of range saturates, implementation specific + testing.expect_value(t, f64_to_i128(f64(1 << 127)), max(i128)) + testing.expect_value(t, f64_to_i128(2 * f64(1 << 127)), max(i128)) +} + +@test +test_f32_to_u128 :: proc(t: ^testing.T) { + testing.expect_value(t, f32_to_u128(2.75), 2) // trunc toward 0 + testing.expect_value(t, f32_to_u128(f32(1 << 80)), u128(1) << 80) // > max(u64) +} + +@test +test_f32_to_i128 :: proc(t: ^testing.T) { + testing.expect_value(t, f32_to_i128(-2.75), -2) // trunc toward 0 + testing.expect_value(t, f32_to_i128(f32(-(1 << 80))), -(i128(1) << 80)) +}