Fix compilation in strict C++11/C++14 mode

Hexadecimal floating-point literals is a C99 feature. gcc/icc/clang support hex-float literals in C++ as an extension, and fail to compile such code in strict C++11 or C++14 mode (i.e. -std=c++11) This patch adds a work-around for when modes where hex-float literals are not supported..
Maratyszcza · Sep 23, 2018 · 5e2bd58 · 5e2bd58
1 parent 4b37bd3
commit 5e2bd58
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Showing 2 changed files with 21 additions and 0 deletions.
diff --git a/include/fp16/fp16.h b/include/fp16/fp16.h
@@ -152,7 +152,11 @@ static inline float fp16_ieee_to_fp32_value(uint16_t h) {
 	 * operate on denormal inputs, and do not produce denormal results.
 	 */
 	const uint32_t exp_offset = UINT32_C(0xE0) << 23;
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) || defined(__GNUC__) && !defined(__STRICT_ANSI__)
 	const float exp_scale = 0x1.0p-112f;
+#else
+	const float exp_scale = fp32_from_bits(UINT32_C(0x7800000));
+#endif
 	const float normalized_value = fp32_from_bits((two_w >> 4) + exp_offset) * exp_scale;
 
 	/*
@@ -207,8 +211,13 @@ static inline float fp16_ieee_to_fp32_value(uint16_t h) {
  * floating-point operations and bitcasts between integer and floating-point variables.
  */
 static inline uint16_t fp16_ieee_from_fp32_value(float f) {
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) || defined(__GNUC__) && !defined(__STRICT_ANSI__)
 	const float scale_to_inf = 0x1.0p+112f;
 	const float scale_to_zero = 0x1.0p-110f;
+#else
+	const float scale_to_inf = fp32_from_bits(UINT32_C(0x77800000));
+	const float scale_to_zero = fp32_from_bits(UINT32_C(0x08800000));
+#endif
 	float base = (fabsf(f) * scale_to_inf) * scale_to_zero;
 
 	const uint32_t w = fp32_to_bits(f);

diff --git a/include/fp16/psimd.h b/include/fp16/psimd.h
@@ -18,7 +18,11 @@ PSIMD_INTRINSIC psimd_f32 fp16_ieee_to_fp32_psimd(psimd_u16 half) {
 	const psimd_u32 shr3_nonsign = (word + word) >> psimd_splat_u32(4);
 
 	const psimd_u32 exp_offset = psimd_splat_u32(UINT32_C(0x70000000));
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) || defined(__GNUC__) && !defined(__STRICT_ANSI__)
 	const psimd_f32 exp_scale = psimd_splat_f32(0x1.0p-112f);
+#else
+	const psimd_f32 exp_scale = psimd_splat_f32(fp32_from_bits(UINT32_C(0x7800000)));
+#endif
 	const psimd_f32 norm_nonsign = psimd_mul_f32((psimd_f32) (shr3_nonsign + exp_offset), exp_scale);
 
 	const psimd_u16 magic_mask = psimd_splat_u16(UINT16_C(0x3E80));
@@ -41,7 +45,11 @@ PSIMD_INTRINSIC psimd_f32x2 fp16_ieee_to_fp32x2_psimd(psimd_u16 half) {
 	const psimd_u32 shr3_nonsign_hi = (word_hi + word_hi) >> psimd_splat_u32(4);
 
 	const psimd_u32 exp_offset = psimd_splat_u32(UINT32_C(0x70000000));
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) || defined(__GNUC__) && !defined(__STRICT_ANSI__)
 	const psimd_f32 exp_scale = psimd_splat_f32(0x1.0p-112f);
+#else
+	const psimd_f32 exp_scale = psimd_splat_f32(fp32_from_bits(UINT32_C(0x7800000)));
+#endif
 	const psimd_f32 norm_nonsign_lo = psimd_mul_f32((psimd_f32) (shr3_nonsign_lo + exp_offset), exp_scale);
 	const psimd_f32 norm_nonsign_hi = psimd_mul_f32((psimd_f32) (shr3_nonsign_hi + exp_offset), exp_scale);
 
@@ -77,7 +85,11 @@ PSIMD_INTRINSIC psimd_f32 fp16_alt_to_fp32_psimd(psimd_u16 half) {
 #else
 	const psimd_u32 exp_offset = psimd_splat_u32(UINT32_C(0x38000000));
 	const psimd_f32 nonsign = (psimd_f32) (shr3_nonsign + exp_offset);
+#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) || defined(__GNUC__) && !defined(__STRICT_ANSI__)
 	const psimd_f32 denorm_bias = psimd_splat_f32(0x1.0p-14f);
+#else
+	const psimd_f32 denorm_bias = psimd_splat_f32(fp32_from_bits(UINT32_C(0x38800000)));
+#endif
 	return (psimd_f32) (sign | (psimd_s32) psimd_sub_f32(psimd_add_f32(nonsign, nonsign), psimd_max_f32(nonsign, denorm_bias)));
 #endif
 }