5 files changed, 71 insertions, 3 deletions
diff --git a/src/runtime/c/gu/bits.c b/src/runtime/c/gu/bits.c
index 8c43b8477..b5696a19c 100644
--- a/src/runtime/c/gu/bits.c
+++ b/src/runtime/c/gu/bits.c
@@ -41,3 +41,36 @@ gu_decode_double(uint64_t u)
 	}
 	return sign ? copysign(ret, -1.0) : ret;
 }
+
+GU_INTERNAL uint64_t
+gu_encode_double(double d)
+{
+	int sign = signbit(d) > 0;
+	unsigned rawexp;
+	uint64_t mantissa;
+
+	switch (fpclassify(d)) {
+	case FP_NAN:
+		rawexp   = 0x7ff;
+		mantissa = 1;
+		break;
+	case FP_INFINITE:
+		rawexp   = 0x7ff;
+		mantissa = 0;
+		break;
+	default: {
+		int exp;
+		mantissa = (uint64_t) scalbn(frexp(d, &exp), 53);
+		mantissa &= ~ (1ULL << 52);
+		exp -= 53;
+
+		rawexp = exp + 1075;
+	}
+	}
+
+    uint64_t u = (((uint64_t) sign) << 63) |
+                 (((uint64_t) rawexp & 0x7ff) << 52) |
+                 mantissa;
+
+	return u;
+}
diff --git a/src/runtime/c/gu/bits.h b/src/runtime/c/gu/bits.h
index edf6a0049..ee619f400 100644
--- a/src/runtime/c/gu/bits.h
+++ b/src/runtime/c/gu/bits.h
@@ -144,6 +144,7 @@ gu_decode_2c64(uint64_t u, GuExn* err)
 GU_INTERNAL_DECL double
 gu_decode_double(uint64_t u);
 
-
+GU_INTERNAL_DECL uint64_t
+gu_encode_double(double d);
 
 #endif // GU_BITS_H_
diff --git a/src/runtime/c/gu/defs.h b/src/runtime/c/gu/defs.h
index 6b531979c..f5472a414 100644
--- a/src/runtime/c/gu/defs.h
+++ b/src/runtime/c/gu/defs.h
@@ -23,6 +23,14 @@
 
 #define restrict __restrict
 
+#elif defined(__MINGW32__)
+
+#define GU_API_DECL
+#define GU_API
+
+#define GU_INTERNAL_DECL
+#define GU_INTERNAL
+
 #else
 
 #define GU_API_DECL
@@ -30,7 +38,9 @@
 
 #define GU_INTERNAL_DECL  __attribute__ ((visibility ("hidden")))
 #define GU_INTERNAL       __attribute__ ((visibility ("hidden")))
+
 #endif
+
 // end MSVC workaround
 
 #include <stddef.h>
diff --git a/src/runtime/c/gu/in.c b/src/runtime/c/gu/in.c
index b36df7924..c241d3086 100644
--- a/src/runtime/c/gu/in.c
+++ b/src/runtime/c/gu/in.c
@@ -152,7 +152,7 @@ gu_in_le(GuIn* in, GuExn* err, int n)
 	uint8_t buf[8];
 	gu_in_bytes(in, buf, n, err);
 	uint64_t u = 0;
-	for (int i = 0; i < n; i++) {
+	for (int i = n-1; i >= 0; i--) {
 		u = u << 8 | buf[i];
 	}
 	return u;
@@ -246,7 +246,7 @@ gu_in_f64le(GuIn* in, GuExn* err)
 GU_API double
 gu_in_f64be(GuIn* in, GuExn* err)
 {
-	return gu_decode_double(gu_in_u64le(in, err));
+	return gu_decode_double(gu_in_u64be(in, err));
 }
 
 static void
diff --git a/src/runtime/c/gu/out.c b/src/runtime/c/gu/out.c
index 7a287cadb..164f483d1 100644
--- a/src/runtime/c/gu/out.c
+++ b/src/runtime/c/gu/out.c
@@ -1,6 +1,7 @@
 #include <gu/seq.h>
 #include <gu/out.h>
 #include <gu/utf8.h>
+#include <gu/bits.h>
 #include <stdio.h>
 
 static bool
@@ -168,8 +169,31 @@ gu_out_is_buffered(GuOut* out);
 extern inline bool
 gu_out_try_u8_(GuOut* restrict out, uint8_t u);
 
+GU_API void
+gu_out_u16be(GuOut* out, uint16_t u, GuExn* err)
+{
+	gu_out_u8(out, (u>>8) & 0xFF, err);
+	gu_out_u8(out, u      & 0xFF, err);
+}
 
+GU_API void
+gu_out_u64be(GuOut* out, uint64_t u, GuExn* err)
+{
+	gu_out_u8(out, (u>>56) & 0xFF, err);
+	gu_out_u8(out, (u>>48) & 0xFF, err);
+	gu_out_u8(out, (u>>40) & 0xFF, err);
+	gu_out_u8(out, (u>>32) & 0xFF, err);
+	gu_out_u8(out, (u>>24) & 0xFF, err);
+	gu_out_u8(out, (u>>16) & 0xFF, err);
+	gu_out_u8(out, (u>>8)  & 0xFF, err);
+	gu_out_u8(out, u       & 0xFF, err);
+}
 
+GU_API void
+gu_out_f64be(GuOut* out, double d, GuExn* err)
+{
+	gu_out_u64be(out, gu_encode_double(d), err);
+}
 
 typedef struct GuBufferedOutStream GuBufferedOutStream;