softfloat: Move addsub_floats to softfloat-parts.c.inc

In preparation for implementing multiple sizes.  Rename to parts_addsub,
split out parts_add/sub_normal for future reuse with muladd.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 62 insertions, 0 deletions

diff --git a/fpu/softfloat-parts-addsub.c.inc b/fpu/softfloat-parts-addsub.c.inc
new file mode 100644
index 0000000000..ae5c1017c5
--- /dev/null
+++ b/fpu/softfloat-parts-addsub.c.inc
@@ -0,0 +1,62 @@
+/*
+ * Floating point arithmetic implementation
+ *
+ * The code in this source file is derived from release 2a of the SoftFloat
+ * IEC/IEEE Floating-point Arithmetic Package. Those parts of the code (and
+ * some later contributions) are provided under that license, as detailed below.
+ * It has subsequently been modified by contributors to the QEMU Project,
+ * so some portions are provided under:
+ *  the SoftFloat-2a license
+ *  the BSD license
+ *  GPL-v2-or-later
+ *
+ * Any future contributions to this file after December 1st 2014 will be
+ * taken to be licensed under the Softfloat-2a license unless specifically
+ * indicated otherwise.
+ */
+
+static void partsN(add_normal)(FloatPartsN *a, FloatPartsN *b)
+{
+    int exp_diff = a->exp - b->exp;
+
+    if (exp_diff > 0) {
+        frac_shrjam(b, exp_diff);
+    } else if (exp_diff < 0) {
+        frac_shrjam(a, -exp_diff);
+        a->exp = b->exp;
+    }
+
+    if (frac_add(a, a, b)) {
+        frac_shrjam(a, 1);
+        a->frac_hi |= DECOMPOSED_IMPLICIT_BIT;
+        a->exp += 1;
+    }
+}
+
+static bool partsN(sub_normal)(FloatPartsN *a, FloatPartsN *b)
+{
+    int exp_diff = a->exp - b->exp;
+    int shift;
+
+    if (exp_diff > 0) {
+        frac_shrjam(b, exp_diff);
+        frac_sub(a, a, b);
+    } else if (exp_diff < 0) {
+        a->exp = b->exp;
+        a->sign ^= 1;
+        frac_shrjam(a, -exp_diff);
+        frac_sub(a, b, a);
+    } else if (frac_sub(a, a, b)) {
+        /* Overflow means that A was less than B. */
+        frac_neg(a);
+        a->sign ^= 1;
+    }
+
+    shift = frac_normalize(a);
+    if (likely(shift < N)) {
+        a->exp -= shift;
+	return true;
+    }
+    a->cls = float_class_zero;
+    return false;
+}