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-rw-r--r--third_party/wasm2c/src/config.cc162
1 files changed, 162 insertions, 0 deletions
diff --git a/third_party/wasm2c/src/config.cc b/third_party/wasm2c/src/config.cc
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index 0000000000..ccf80e68ea
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+++ b/third_party/wasm2c/src/config.cc
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2016 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "wabt/config.h"
+
+#include <cstdarg>
+#include <cstdio>
+
+#if COMPILER_IS_MSVC && _M_X64
+#include <emmintrin.h>
+#elif COMPILER_IS_MSVC && _M_IX86
+#include <float.h>
+#endif
+
+/* c99-style vsnprintf for MSVC < 2015. See http://stackoverflow.com/a/8712996
+ using _snprintf or vsnprintf will not-properly null-terminate, and will return
+ -1 instead of the number of characters needed on overflow. */
+#if COMPILER_IS_MSVC
+int wabt_vsnprintf(char* str, size_t size, const char* format, va_list ap) {
+ int result = -1;
+ if (size != 0) {
+ result = _vsnprintf_s(str, size, _TRUNCATE, format, ap);
+ }
+ if (result == -1) {
+ result = _vscprintf(format, ap);
+ }
+ return result;
+}
+
+#if !HAVE_SNPRINTF
+int wabt_snprintf(char* str, size_t size, const char* format, ...) {
+ va_list args;
+ va_start(args, format);
+ int result = wabt_vsnprintf(str, size, format, args);
+ va_end(args);
+ return result;
+}
+#endif
+#endif
+
+#if COMPILER_IS_MSVC && _M_IX86
+// Allow the following functions to change the floating-point environment (e.g.
+// update to 64-bit precision in the mantissa). This is only needed for x87
+// floats, which are only used on MSVC 32-bit.
+#pragma fenv_access(on)
+namespace {
+
+typedef unsigned int FPControl;
+
+FPControl Set64BitPrecisionControl() {
+ FPControl old_ctrl = _control87(0, 0);
+ _control87(_PC_64, _MCW_PC);
+ return old_ctrl;
+}
+
+void ResetPrecisionControl(FPControl old_ctrl) {
+ _control87(old_ctrl, _MCW_PC);
+}
+
+} // end of anonymous namespace
+#endif
+
+double wabt_convert_uint64_to_double(uint64_t x) {
+#if COMPILER_IS_MSVC && _M_X64
+ // MSVC on x64 generates uint64 -> float conversions but doesn't do
+ // round-to-nearest-ties-to-even, which is required by WebAssembly.
+ __m128d result = _mm_setzero_pd();
+ if (x & 0x8000000000000000ULL) {
+ result = _mm_cvtsi64_sd(result, (x >> 1) | (x & 1));
+ result = _mm_add_sd(result, result);
+ } else {
+ result = _mm_cvtsi64_sd(result, x);
+ }
+ return _mm_cvtsd_f64(result);
+#elif COMPILER_IS_MSVC && _M_IX86
+ // MSVC on x86 converts from i64 -> double -> float, which causes incorrect
+ // rounding. Using the x87 float stack instead preserves the correct
+ // rounding.
+ FPControl old_ctrl = Set64BitPrecisionControl();
+ static const double c = 18446744073709551616.0;
+ double result;
+ __asm fild x;
+ if (x & 0x8000000000000000ULL) {
+ __asm fadd c;
+ }
+ __asm fstp result;
+ ResetPrecisionControl(old_ctrl);
+ return result;
+#else
+ return static_cast<double>(x);
+#endif
+}
+
+float wabt_convert_uint64_to_float(uint64_t x) {
+#if COMPILER_IS_MSVC && _M_X64
+ // MSVC on x64 generates uint64 -> float conversions but doesn't do
+ // round-to-nearest-ties-to-even, which is required by WebAssembly.
+ __m128 result = _mm_setzero_ps();
+ if (x & 0x8000000000000000ULL) {
+ result = _mm_cvtsi64_ss(result, (x >> 1) | (x & 1));
+ result = _mm_add_ss(result, result);
+ } else {
+ result = _mm_cvtsi64_ss(result, x);
+ }
+ return _mm_cvtss_f32(result);
+#elif COMPILER_IS_MSVC && _M_IX86
+ // MSVC on x86 converts from i64 -> double -> float, which causes incorrect
+ // rounding. Using the x87 float stack instead preserves the correct
+ // rounding.
+ FPControl old_ctrl = Set64BitPrecisionControl();
+ static const float c = 18446744073709551616.0f;
+ float result;
+ __asm fild x;
+ if (x & 0x8000000000000000ULL) {
+ __asm fadd c;
+ }
+ __asm fstp result;
+ ResetPrecisionControl(old_ctrl);
+ return result;
+#else
+ return static_cast<float>(x);
+#endif
+}
+
+double wabt_convert_int64_to_double(int64_t x) {
+#if COMPILER_IS_MSVC && _M_IX86
+ double result;
+ __asm fild x;
+ __asm fstp result;
+ return result;
+#else
+ return static_cast<double>(x);
+#endif
+}
+
+float wabt_convert_int64_to_float(int64_t x) {
+#if COMPILER_IS_MSVC && _M_IX86
+ float result;
+ __asm fild x;
+ __asm fstp result;
+ return result;
+#else
+ return static_cast<float>(x);
+#endif
+}
+
+#if COMPILER_IS_MSVC && _M_IX86
+#pragma fenv_access(off)
+#endif