283 changes: 283 additions & 0 deletions libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h
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//===- darwin-aarch64 floating point env manipulation functions -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIBC_SRC_SUPPORT_FPUTIL_AARCH64_FENV_DARWIN_IMPL_H
#define LLVM_LIBC_SRC_SUPPORT_FPUTIL_AARCH64_FENV_DARWIN_IMPL_H

#include "src/__support/architectures.h"

#if !defined(LLVM_LIBC_ARCH_AARCH64) || !defined(__APPLE__)
#error "Invalid include"
#endif

#include <arm_acle.h>
#include <fenv.h>
#include <stdint.h>

#include "src/__support/FPUtil/FPBits.h"

namespace __llvm_libc {
namespace fputil {

struct FEnv {
struct FPState {
uint64_t StatusWord;
uint64_t ControlWord;
};

static_assert(
sizeof(fenv_t) == sizeof(FPState),
"Internal floating point state does not match the public fenv_t type.");

static constexpr uint32_t TONEAREST = 0x0;
static constexpr uint32_t UPWARD = 0x1;
static constexpr uint32_t DOWNWARD = 0x2;
static constexpr uint32_t TOWARDZERO = 0x3;

// These will be the exception flags we use for exception values normalized
// from both status word and control word.
// We add EX_ prefix to the names since macOS <math.h> defines OVERFLOW and
// UNDERFLOW macros.
static constexpr uint32_t EX_INVALID = 0x1;
static constexpr uint32_t EX_DIVBYZERO = 0x2;
static constexpr uint32_t EX_OVERFLOW = 0x4;
static constexpr uint32_t EX_UNDERFLOW = 0x8;
static constexpr uint32_t EX_INEXACT = 0x10;
// __APPLE__ ARM64 has an extra flag that is raised when a denormal is flushed
// to zero.
static constexpr uint32_t EX_FLUSHTOZERO = 0x20;

// Zero-th bit is the first bit.
static constexpr uint32_t ROUNDING_CONTROL_BIT_POSITION = 22;

// In addition to the 5 floating point exceptions, macOS on arm64 defines
// another floating point exception: FE_FLUSHTOZERO, which is controlled by
// __fpcr_flush_to_zero bit in the FPCR register. This control bit is
// located in a different place from FE_FLUSHTOZERO status bit relative to
// the other exceptions.
static inline uint32_t exception_value_from_status(int status) {
return (status & FE_INVALID ? EX_INVALID : 0) |
(status & FE_DIVBYZERO ? EX_DIVBYZERO : 0) |
(status & FE_OVERFLOW ? EX_OVERFLOW : 0) |
(status & FE_UNDERFLOW ? EX_UNDERFLOW : 0) |
(status & FE_INEXACT ? EX_INEXACT : 0) |
(status & FE_FLUSHTOZERO ? EX_FLUSHTOZERO : 0);
}

static inline uint32_t exception_value_from_control(int control) {
return (control & __fpcr_trap_invalid ? EX_INVALID : 0) |
(control & __fpcr_trap_divbyzero ? EX_DIVBYZERO : 0) |
(control & __fpcr_trap_overflow ? EX_OVERFLOW : 0) |
(control & __fpcr_trap_underflow ? EX_UNDERFLOW : 0) |
(control & __fpcr_trap_inexact ? EX_INEXACT : 0) |
(control & __fpcr_flush_to_zero ? EX_FLUSHTOZERO : 0);
}

static inline int exception_value_to_status(uint32_t excepts) {
return (excepts & EX_INVALID ? FE_INVALID : 0) |
(excepts & EX_DIVBYZERO ? FE_DIVBYZERO : 0) |
(excepts & EX_OVERFLOW ? FE_OVERFLOW : 0) |
(excepts & EX_UNDERFLOW ? FE_UNDERFLOW : 0) |
(excepts & EX_INEXACT ? FE_INEXACT : 0) |
(excepts & EX_FLUSHTOZERO ? FE_FLUSHTOZERO : 0);
}

static inline int exception_value_to_control(uint32_t excepts) {
return (excepts & EX_INVALID ? __fpcr_trap_invalid : 0) |
(excepts & EX_DIVBYZERO ? __fpcr_trap_divbyzero : 0) |
(excepts & EX_OVERFLOW ? __fpcr_trap_overflow : 0) |
(excepts & EX_UNDERFLOW ? __fpcr_trap_underflow : 0) |
(excepts & EX_INEXACT ? __fpcr_trap_inexact : 0) |
(excepts & EX_FLUSHTOZERO ? __fpcr_flush_to_zero : 0);
}

static uint32_t get_control_word() { return __arm_rsr("fpcr"); }

static void set_control_word(uint32_t fpcr) { __arm_wsr("fpcr", fpcr); }

static uint32_t get_status_word() { return __arm_rsr("fpsr"); }

static void set_status_word(uint32_t fpsr) { __arm_wsr("fpsr", fpsr); }
};

static inline int enable_except(int excepts) {
uint32_t new_excepts = FEnv::exception_value_from_status(excepts);
uint32_t control_word = FEnv::get_control_word();
uint32_t old_excepts = FEnv::exception_value_from_control(control_word);
if (new_excepts != old_excepts) {
control_word |= FEnv::exception_value_to_control(new_excepts);
FEnv::set_control_word(control_word);
}
return FEnv::exception_value_to_status(old_excepts);
}

static inline int disable_except(int excepts) {
uint32_t disabled_excepts = FEnv::exception_value_from_status(excepts);
uint32_t control_word = FEnv::get_control_word();
uint32_t old_excepts = FEnv::exception_value_from_control(control_word);
control_word &= ~FEnv::exception_value_to_control(disabled_excepts);
FEnv::set_control_word(control_word);
return FEnv::exception_value_to_status(old_excepts);
}

static inline int get_except() {
uint32_t control_word = FEnv::get_control_word();
uint32_t enabled_excepts = FEnv::exception_value_from_control(control_word);
return FEnv::exception_value_to_status(enabled_excepts);
}

static inline int clear_except(int excepts) {
uint32_t status_word = FEnv::get_status_word();
uint32_t except_value = FEnv::exception_value_from_status(excepts);
status_word &= ~FEnv::exception_value_to_status(except_value);
FEnv::set_status_word(status_word);
return 0;
}

static inline int test_except(int excepts) {
uint32_t statusWord = FEnv::get_status_word();
uint32_t ex_value = FEnv::exception_value_from_status(excepts);
return statusWord & FEnv::exception_value_to_status(ex_value);
}

static inline int set_except(int excepts) {
uint32_t status_word = FEnv::get_status_word();
uint32_t new_exceptions = FEnv::exception_value_from_status(excepts);
status_word |= FEnv::exception_value_to_status(new_exceptions);
FEnv::set_status_word(status_word);
return 0;
}

static inline int raise_except(int excepts) {
float zero = 0.0f;
float one = 1.0f;
float large_value = float(FPBits<float>(FPBits<float>::MAX_NORMAL));
float small_value = float(FPBits<float>(FPBits<float>::MIN_NORMAL));
auto divfunc = [](float a, float b) {
__asm__ __volatile__("ldr s0, %0\n\t"
"ldr s1, %1\n\t"
"fdiv s0, s0, s1\n\t"
: // No outputs
: "m"(a), "m"(b)
: "s0", "s1" /* s0 and s1 are clobbered */);
};

uint32_t to_raise = FEnv::exception_value_from_status(excepts);
int result = 0;

if (to_raise & FEnv::EX_INVALID) {
divfunc(zero, zero);
uint32_t status_word = FEnv::get_status_word();
if (!(FEnv::exception_value_from_status(status_word) & FEnv::EX_INVALID))
result = -1;
}

if (to_raise & FEnv::EX_DIVBYZERO) {
divfunc(one, zero);
uint32_t status_word = FEnv::get_status_word();
if (!(FEnv::exception_value_from_status(status_word) & FEnv::EX_DIVBYZERO))
result = -1;
}
if (to_raise & FEnv::EX_OVERFLOW) {
divfunc(large_value, small_value);
uint32_t status_word = FEnv::get_status_word();
if (!(FEnv::exception_value_from_status(status_word) & FEnv::EX_OVERFLOW))
result = -1;
}
if (to_raise & FEnv::EX_UNDERFLOW) {
divfunc(small_value, large_value);
uint32_t status_word = FEnv::get_status_word();
if (!(FEnv::exception_value_from_status(status_word) & FEnv::EX_UNDERFLOW))
result = -1;
}
if (to_raise & FEnv::EX_INEXACT) {
float two = 2.0f;
float three = 3.0f;
// 2.0 / 3.0 cannot be represented exactly in any radix 2 floating point
// format.
divfunc(two, three);
uint32_t status_word = FEnv::get_status_word();
if (!(FEnv::exception_value_from_status(status_word) & FEnv::EX_INEXACT))
result = -1;
}
if (to_raise & FEnv::EX_FLUSHTOZERO) {
// TODO: raise the flush to zero floating point exception.
result = -1;
}
return result;
}

static inline int get_round() {
uint32_t rounding_mode =
(FEnv::get_control_word() >> FEnv::ROUNDING_CONTROL_BIT_POSITION) & 0x3;
switch (rounding_mode) {
case FEnv::TONEAREST:
return FE_TONEAREST;
case FEnv::DOWNWARD:
return FE_DOWNWARD;
case FEnv::UPWARD:
return FE_UPWARD;
case FEnv::TOWARDZERO:
return FE_TOWARDZERO;
default:
return -1; // Error value.
}
}

static inline int set_round(int mode) {
uint16_t bit_value;
switch (mode) {
case FE_TONEAREST:
bit_value = FEnv::TONEAREST;
break;
case FE_DOWNWARD:
bit_value = FEnv::DOWNWARD;
break;
case FE_UPWARD:
bit_value = FEnv::UPWARD;
break;
case FE_TOWARDZERO:
bit_value = FEnv::TOWARDZERO;
break;
default:
return 1; // To indicate failure
}

uint32_t control_word = FEnv::get_control_word();
control_word &= ~(0x3 << FEnv::ROUNDING_CONTROL_BIT_POSITION);
control_word |= (bit_value << FEnv::ROUNDING_CONTROL_BIT_POSITION);
FEnv::set_control_word(control_word);

return 0;
}

static inline int get_env(fenv_t *envp) {
FEnv::FPState *state = reinterpret_cast<FEnv::FPState *>(envp);
state->ControlWord = FEnv::get_control_word();
state->StatusWord = FEnv::get_status_word();
return 0;
}

static inline int set_env(const fenv_t *envp) {
if (envp == FE_DFL_ENV) {
// Default status and control words bits are all zeros so we just
// write zeros.
FEnv::set_status_word(0);
FEnv::set_control_word(0);
return 0;
}
const FEnv::FPState *state = reinterpret_cast<const FEnv::FPState *>(envp);
FEnv::set_control_word(state->ControlWord);
FEnv::set_status_word(state->StatusWord);
return 0;
}

} // namespace fputil
} // namespace __llvm_libc

#endif // LLVM_LIBC_SRC_SUPPORT_FPUTIL_AARCH64_FENV_DARWIN_IMPL_H
3 changes: 2 additions & 1 deletion libc/src/__support/common.h
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Expand Up @@ -19,7 +19,8 @@
#define LLVM_LIBC_FUNCTION_ATTR
#endif

#ifdef LLVM_LIBC_PUBLIC_PACKAGING
// MacOS needs to be excluded because it does not support aliasing.
#if defined(LLVM_LIBC_PUBLIC_PACKAGING) && (!defined(__APPLE__))
#define LLVM_LIBC_FUNCTION(type, name, arglist) \
LLVM_LIBC_FUNCTION_ATTR decltype(__llvm_libc::name) \
__##name##_impl__ __asm__(#name); \
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5 changes: 3 additions & 2 deletions libc/src/__support/str_to_float.h
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Original file line number Diff line number Diff line change
Expand Up @@ -458,8 +458,9 @@ template <> class ClingerConsts<double> {
#if defined(LONG_DOUBLE_IS_DOUBLE)
template <> class ClingerConsts<long double> {
public:
static constexpr long double POWERS_OF_TEN_ARRAY[] =
ClingerConsts<double>::POWERS_OF_TEN_ARRAY;
static constexpr long double POWERS_OF_TEN_ARRAY[] = {
1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10, 1e11,
1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, 1e20, 1e21, 1e22};
static constexpr int32_t EXACT_POWERS_OF_TEN =
ClingerConsts<double>::EXACT_POWERS_OF_TEN;
static constexpr int32_t DIGITS_IN_MANTISSA =
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8 changes: 5 additions & 3 deletions libc/test/src/fenv/CMakeLists.txt
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Expand Up @@ -85,11 +85,13 @@ add_libc_unittest(
libc.src.fenv.fegetexcept
)

if (NOT (LLVM_USE_SANITIZER OR (${LIBC_TARGET_OS} STREQUAL "windows")))
if (NOT (LLVM_USE_SANITIZER OR (${LIBC_TARGET_OS} STREQUAL "windows")
OR (${LIBC_TARGET_OS} STREQUAL "darwin")))
# Sanitizers don't like SIGFPE. So, we will run the
# tests which raise SIGFPE only in non-sanitizer builds.
# The tests are also disabled for Windows as they fail currently.
# TODO: Investigate and fix the windows failures and enable them for Windows.
# The tests are also disabled for Windows and MacOS as they fail currently.
# TODO: Investigate and fix the windows failures and enable them for Windows
# and MacOS.
add_fp_unittest(
enabled_exceptions_test
SUITE
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12 changes: 6 additions & 6 deletions libc/test/src/math/RoundToIntegerTest.h
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Original file line number Diff line number Diff line change
Expand Up @@ -73,12 +73,12 @@ class RoundToIntegerTestTemplate : public __llvm_libc::testing::Test {

public:
void SetUp() override {
#if math_errhandling & MATH_ERREXCEPT
// We will disable all exceptions so that the test will not
// crash with SIGFPE. We can still use fetestexcept to check
// if the appropriate flag was raised.
__llvm_libc::fputil::disable_except(FE_ALL_EXCEPT);
#endif
if (math_errhandling & MATH_ERREXCEPT) {
// We will disable all exceptions so that the test will not
// crash with SIGFPE. We can still use fetestexcept to check
// if the appropriate flag was raised.
__llvm_libc::fputil::disable_except(FE_ALL_EXCEPT);
}
}

void do_infinity_and_na_n_test(RoundToIntegerFunc func) {
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4 changes: 2 additions & 2 deletions libc/test/src/stdlib/strtold_test.cpp
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Expand Up @@ -175,12 +175,12 @@ TEST_F(LlvmLibcStrToLDTest, SmallNormalTests) {
TEST_F(LlvmLibcStrToLDTest, ComplexHexadecimalTests) {
run_test("0x1p16383", 9, 0x7ff0000000000000,
(__uint128_t(0x7ffe800000) << 40),
(__uint128_t(0x7ffe000000000000) << 64));
(__uint128_t(0x7ffe000000000000) << 64), ERANGE);
run_test("0x123456789abcdef", 17, 0x43723456789abcdf,
(__uint128_t(0x403791a2b3) << 40) + __uint128_t(0xc4d5e6f780),
(__uint128_t(0x403723456789abcd) << 64) +
__uint128_t(0xef00000000000000));
run_test("0x123456789abcdef0123456789ABCDEF", 33, 0x7ff0000000000000,
run_test("0x123456789abcdef0123456789ABCDEF", 33, 0x47723456789abcdf,
(__uint128_t(0x407791a2b3) << 40) + __uint128_t(0xc4d5e6f781),
(__uint128_t(0x407723456789abcd) << 64) +
__uint128_t(0xef0123456789abce));
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