add convert(Float32, Float16)

base/float16.jl

@@ -0,0 +1,43 @@
+
+function convert(::Type{Float32}, val::Float16)
+    val = uint32(reinterpret(Uint16, val))
+    sign = (val & 0x8000) >> 15
+    exp  = (val & 0x7c00) >> 10
+    sig  = (val & 0x3ff) >> 0
+    ret::Uint32
+
+    if exp == 0
+        if sig == 0
+            sign = sign << 31
+            ret = sign | exp | sig
+        else
+            n_bit = 1
+            bit = 0x0200
+            while (bit & sig) == 0
+                n_bit = n_bit + 1
+                bit = bit >> 1
+            end
+            sign = sign << 31
+            exp = (-14 - n_bit + 127) << 23
+            sig = ((sig & (~bit)) << n_bit) << (23 - 10)
+            ret = sign | exp | sig
+        end
+    elseif exp == 0x1f
+        if sig == 0
+            if sign == 0
+                ret = 0x7f800000
+            else
+                ret = 0xff800000
+            end
+        else
+            ret = 0xffffffff
+        end
+    else
+        sign = sign << 31
+        exp  = (exp - 15 + 127) << 23
+        sig  = sig << (23 - 10)
+        ret = sign | exp | sig
+    end
+    return reinterpret(Float32, ret)
+end
+