converting uint bits back into floats
R=rsc
DELTA=32 (32 added, 0 deleted, 0 changed)
OCL=19084
CL=19091
diff --git a/src/cmd/gc/sys.go b/src/cmd/gc/sys.go
index 72e36a0..910bbd8 100644
--- a/src/cmd/gc/sys.go
+++ b/src/cmd/gc/sys.go
@@ -51,6 +51,8 @@
export func NaN() float64; // return a NaN
export func float32bits(float32) uint32; // raw bits
export func float64bits(float64) uint64; // raw bits
+export func float32frombits(uint32) float32; // raw bits
+export func float64frombits(uint64) float64; // raw bits
export func newmap(keysize int, valsize int,
keyalg int, valalg int,
diff --git a/src/cmd/gc/sysimport.c b/src/cmd/gc/sysimport.c
index 9ee99a1..64dd1a9 100644
--- a/src/cmd/gc/sysimport.c
+++ b/src/cmd/gc/sysimport.c
@@ -41,6 +41,8 @@
"export func sys.NaN () (? float64)\n"
"export func sys.float32bits (? float32) (? uint32)\n"
"export func sys.float64bits (? float64) (? uint64)\n"
+ "export func sys.float32frombits (? uint32) (? float32)\n"
+ "export func sys.float64frombits (? uint64) (? float64)\n"
"export func sys.newmap (keysize int, valsize int, keyalg int, valalg int, hint int) (hmap *map[any] any)\n"
"export func sys.mapaccess1 (hmap *map[any] any, key any) (val any)\n"
"export func sys.mapaccess2 (hmap *map[any] any, key any) (val any, pres bool)\n"
diff --git a/src/runtime/runtime.c b/src/runtime/runtime.c
index a75a7f8..c84b210 100644
--- a/src/runtime/runtime.c
+++ b/src/runtime/runtime.c
@@ -204,6 +204,19 @@
return u.f;
}
+static float32
+float32frombits(uint32 i)
+{
+ // The obvious cast-and-pointer code is technically
+ // not valid, and gcc miscompiles it. Use a union instead.
+ union {
+ float32 f;
+ uint32 i;
+ } u;
+ u.i = i;
+ return u.f;
+}
+
bool
isInf(float64 f, int32 sign)
{
@@ -387,6 +400,21 @@
FLUSH(&iou);
}
+// func float32frombits(uint32) float32; // raw bits to float32
+void
+sys·float32frombits(uint32 uin, float32 dou)
+{
+ dou = float32frombits(uin);
+ FLUSH(&dou);
+}
+
+// func float64frombits(uint64) float64; // raw bits to float64
+void
+sys·float64frombits(uint64 uin, float64 dou)
+{
+ dou = float64frombits(uin);
+ FLUSH(&dou);
+}
static int32 argc;
static uint8** argv;
