aboutsummaryrefslogtreecommitdiff
path: root/contrib/compiler-rt/lib/comparedf2.c
diff options
context:
space:
mode:
Diffstat (limited to 'contrib/compiler-rt/lib/comparedf2.c')
-rw-r--r--contrib/compiler-rt/lib/comparedf2.c132
1 files changed, 132 insertions, 0 deletions
diff --git a/contrib/compiler-rt/lib/comparedf2.c b/contrib/compiler-rt/lib/comparedf2.c
new file mode 100644
index 000000000000..fe35fd80aadd
--- /dev/null
+++ b/contrib/compiler-rt/lib/comparedf2.c
@@ -0,0 +1,132 @@
+//===-- lib/comparedf2.c - Double-precision comparisons -----------*- C -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// // This file implements the following soft-float comparison routines:
+//
+// __eqdf2 __gedf2 __unorddf2
+// __ledf2 __gtdf2
+// __ltdf2
+// __nedf2
+//
+// The semantics of the routines grouped in each column are identical, so there
+// is a single implementation for each, and wrappers to provide the other names.
+//
+// The main routines behave as follows:
+//
+// __ledf2(a,b) returns -1 if a < b
+// 0 if a == b
+// 1 if a > b
+// 1 if either a or b is NaN
+//
+// __gedf2(a,b) returns -1 if a < b
+// 0 if a == b
+// 1 if a > b
+// -1 if either a or b is NaN
+//
+// __unorddf2(a,b) returns 0 if both a and b are numbers
+// 1 if either a or b is NaN
+//
+// Note that __ledf2( ) and __gedf2( ) are identical except in their handling of
+// NaN values.
+//
+//===----------------------------------------------------------------------===//
+
+#define DOUBLE_PRECISION
+#include "fp_lib.h"
+
+enum LE_RESULT {
+ LE_LESS = -1,
+ LE_EQUAL = 0,
+ LE_GREATER = 1,
+ LE_UNORDERED = 1
+};
+
+enum LE_RESULT __ledf2(fp_t a, fp_t b) {
+
+ const srep_t aInt = toRep(a);
+ const srep_t bInt = toRep(b);
+ const rep_t aAbs = aInt & absMask;
+ const rep_t bAbs = bInt & absMask;
+
+ // If either a or b is NaN, they are unordered.
+ if (aAbs > infRep || bAbs > infRep) return LE_UNORDERED;
+
+ // If a and b are both zeros, they are equal.
+ if ((aAbs | bAbs) == 0) return LE_EQUAL;
+
+ // If at least one of a and b is positive, we get the same result comparing
+ // a and b as signed integers as we would with a floating-point compare.
+ if ((aInt & bInt) >= 0) {
+ if (aInt < bInt) return LE_LESS;
+ else if (aInt == bInt) return LE_EQUAL;
+ else return LE_GREATER;
+ }
+
+ // Otherwise, both are negative, so we need to flip the sense of the
+ // comparison to get the correct result. (This assumes a twos- or ones-
+ // complement integer representation; if integers are represented in a
+ // sign-magnitude representation, then this flip is incorrect).
+ else {
+ if (aInt > bInt) return LE_LESS;
+ else if (aInt == bInt) return LE_EQUAL;
+ else return LE_GREATER;
+ }
+}
+
+enum GE_RESULT {
+ GE_LESS = -1,
+ GE_EQUAL = 0,
+ GE_GREATER = 1,
+ GE_UNORDERED = -1 // Note: different from LE_UNORDERED
+};
+
+enum GE_RESULT __gedf2(fp_t a, fp_t b) {
+
+ const srep_t aInt = toRep(a);
+ const srep_t bInt = toRep(b);
+ const rep_t aAbs = aInt & absMask;
+ const rep_t bAbs = bInt & absMask;
+
+ if (aAbs > infRep || bAbs > infRep) return GE_UNORDERED;
+ if ((aAbs | bAbs) == 0) return GE_EQUAL;
+ if ((aInt & bInt) >= 0) {
+ if (aInt < bInt) return GE_LESS;
+ else if (aInt == bInt) return GE_EQUAL;
+ else return GE_GREATER;
+ } else {
+ if (aInt > bInt) return GE_LESS;
+ else if (aInt == bInt) return GE_EQUAL;
+ else return GE_GREATER;
+ }
+}
+
+int __unorddf2(fp_t a, fp_t b) {
+ const rep_t aAbs = toRep(a) & absMask;
+ const rep_t bAbs = toRep(b) & absMask;
+ return aAbs > infRep || bAbs > infRep;
+}
+
+// The following are alternative names for the preceeding routines.
+
+enum LE_RESULT __eqdf2(fp_t a, fp_t b) {
+ return __ledf2(a, b);
+}
+
+enum LE_RESULT __ltdf2(fp_t a, fp_t b) {
+ return __ledf2(a, b);
+}
+
+enum LE_RESULT __nedf2(fp_t a, fp_t b) {
+ return __ledf2(a, b);
+}
+
+enum GE_RESULT __gtdf2(fp_t a, fp_t b) {
+ return __gedf2(a, b);
+}
+