135 lines
3.9 KiB
C
135 lines
3.9 KiB
C
//===-- lib/comparedf2.c - Double-precision comparisons -----------*- C -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// // This file implements the following soft-float comparison routines:
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//
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// __eqdf2 __gedf2 __unorddf2
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// __ledf2 __gtdf2
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// __ltdf2
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// __nedf2
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//
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// The semantics of the routines grouped in each column are identical, so there
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// is a single implementation for each, and wrappers to provide the other names.
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//
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// The main routines behave as follows:
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//
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// __ledf2(a,b) returns -1 if a < b
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// 0 if a == b
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// 1 if a > b
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// 1 if either a or b is NaN
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//
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// __gedf2(a,b) returns -1 if a < b
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// 0 if a == b
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// 1 if a > b
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// -1 if either a or b is NaN
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//
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// __unorddf2(a,b) returns 0 if both a and b are numbers
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// 1 if either a or b is NaN
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//
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// Note that __ledf2( ) and __gedf2( ) are identical except in their handling of
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// NaN values.
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//
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//===----------------------------------------------------------------------===//
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#define DOUBLE_PRECISION
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#include "fp_lib.h"
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enum LE_RESULT {
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LE_LESS = -1,
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LE_EQUAL = 0,
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LE_GREATER = 1,
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LE_UNORDERED = 1
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};
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enum LE_RESULT __ledf2(fp_t a, fp_t b) {
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const srep_t aInt = toRep(a);
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const srep_t bInt = toRep(b);
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const rep_t aAbs = aInt & absMask;
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const rep_t bAbs = bInt & absMask;
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// If either a or b is NaN, they are unordered.
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if (aAbs > infRep || bAbs > infRep) return LE_UNORDERED;
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// If a and b are both zeros, they are equal.
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if ((aAbs | bAbs) == 0) return LE_EQUAL;
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// If at least one of a and b is positive, we get the same result comparing
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// a and b as signed integers as we would with a floating-point compare.
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if ((aInt & bInt) >= 0) {
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if (aInt < bInt) return LE_LESS;
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else if (aInt == bInt) return LE_EQUAL;
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else return LE_GREATER;
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}
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// Otherwise, both are negative, so we need to flip the sense of the
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// comparison to get the correct result. (This assumes a twos- or ones-
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// complement integer representation; if integers are represented in a
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// sign-magnitude representation, then this flip is incorrect).
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else {
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if (aInt > bInt) return LE_LESS;
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else if (aInt == bInt) return LE_EQUAL;
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else return LE_GREATER;
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}
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}
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enum GE_RESULT {
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GE_LESS = -1,
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GE_EQUAL = 0,
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GE_GREATER = 1,
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GE_UNORDERED = -1 // Note: different from LE_UNORDERED
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};
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enum GE_RESULT __gedf2(fp_t a, fp_t b) {
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const srep_t aInt = toRep(a);
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const srep_t bInt = toRep(b);
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const rep_t aAbs = aInt & absMask;
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const rep_t bAbs = bInt & absMask;
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if (aAbs > infRep || bAbs > infRep) return GE_UNORDERED;
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if ((aAbs | bAbs) == 0) return GE_EQUAL;
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if ((aInt & bInt) >= 0) {
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if (aInt < bInt) return GE_LESS;
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else if (aInt == bInt) return GE_EQUAL;
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else return GE_GREATER;
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} else {
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if (aInt > bInt) return GE_LESS;
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else if (aInt == bInt) return GE_EQUAL;
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else return GE_GREATER;
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}
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}
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ARM_EABI_FNALIAS(dcmpun, unorddf2)
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int __unorddf2(fp_t a, fp_t b) {
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const rep_t aAbs = toRep(a) & absMask;
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const rep_t bAbs = toRep(b) & absMask;
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return aAbs > infRep || bAbs > infRep;
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}
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// The following are alternative names for the preceeding routines.
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enum LE_RESULT __eqdf2(fp_t a, fp_t b) {
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return __ledf2(a, b);
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}
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enum LE_RESULT __ltdf2(fp_t a, fp_t b) {
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return __ledf2(a, b);
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}
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enum LE_RESULT __nedf2(fp_t a, fp_t b) {
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return __ledf2(a, b);
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}
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enum GE_RESULT __gtdf2(fp_t a, fp_t b) {
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return __gedf2(a, b);
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}
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