forked from OSchip/llvm-project
Refactor addsf3.c and adddf3.c.
Differential Revision: http://reviews.llvm.org/D3885 llvm-svn: 209740
This commit is contained in:
Joerg Sonnenberger
parent
4aeb3c0a4c
commit
d21cd147d0
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@ -13,140 +13,10 @@
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//===----------------------------------------------------------------------===//
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#define DOUBLE_PRECISION
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#include "fp_lib.h"
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#include "fp_add_impl.inc"
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ARM_EABI_FNALIAS(dadd, adddf3)
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COMPILER_RT_ABI fp_t
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__adddf3(fp_t a, fp_t b) {
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rep_t aRep = toRep(a);
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rep_t bRep = toRep(b);
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const rep_t aAbs = aRep & absMask;
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const rep_t bAbs = bRep & absMask;
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// Detect if a or b is zero, infinity, or NaN.
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if (aAbs - 1U >= infRep - 1U || bAbs - 1U >= infRep - 1U) {
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// NaN + anything = qNaN
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if (aAbs > infRep) return fromRep(toRep(a) | quietBit);
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// anything + NaN = qNaN
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if (bAbs > infRep) return fromRep(toRep(b) | quietBit);
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if (aAbs == infRep) {
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// +/-infinity + -/+infinity = qNaN
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if ((toRep(a) ^ toRep(b)) == signBit) return fromRep(qnanRep);
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// +/-infinity + anything remaining = +/- infinity
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else return a;
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}
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// anything remaining + +/-infinity = +/-infinity
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if (bAbs == infRep) return b;
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// zero + anything = anything
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if (!aAbs) {
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// but we need to get the sign right for zero + zero
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if (!bAbs) return fromRep(toRep(a) & toRep(b));
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else return b;
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}
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// anything + zero = anything
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if (!bAbs) return a;
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}
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// Swap a and b if necessary so that a has the larger absolute value.
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if (bAbs > aAbs) {
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const rep_t temp = aRep;
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aRep = bRep;
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bRep = temp;
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}
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// Extract the exponent and significand from the (possibly swapped) a and b.
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int aExponent = aRep >> significandBits & maxExponent;
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int bExponent = bRep >> significandBits & maxExponent;
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rep_t aSignificand = aRep & significandMask;
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rep_t bSignificand = bRep & significandMask;
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// Normalize any denormals, and adjust the exponent accordingly.
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if (aExponent == 0) aExponent = normalize(&aSignificand);
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if (bExponent == 0) bExponent = normalize(&bSignificand);
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// The sign of the result is the sign of the larger operand, a. If they
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// have opposite signs, we are performing a subtraction; otherwise addition.
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const rep_t resultSign = aRep & signBit;
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const bool subtraction = (aRep ^ bRep) & signBit;
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// Shift the significands to give us round, guard and sticky, and or in the
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// implicit significand bit. (If we fell through from the denormal path it
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// was already set by normalize( ), but setting it twice won't hurt
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// anything.)
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aSignificand = (aSignificand | implicitBit) << 3;
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bSignificand = (bSignificand | implicitBit) << 3;
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// Shift the significand of b by the difference in exponents, with a sticky
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// bottom bit to get rounding correct.
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const unsigned int align = aExponent - bExponent;
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if (align) {
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if (align < typeWidth) {
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const bool sticky = bSignificand << (typeWidth - align);
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bSignificand = bSignificand >> align | sticky;
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} else {
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bSignificand = 1; // sticky; b is known to be non-zero.
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}
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}
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if (subtraction) {
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aSignificand -= bSignificand;
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// If a == -b, return +zero.
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if (aSignificand == 0) return fromRep(0);
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// If partial cancellation occurred, we need to left-shift the result
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// and adjust the exponent:
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if (aSignificand < implicitBit << 3) {
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const int shift = rep_clz(aSignificand) - rep_clz(implicitBit << 3);
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aSignificand <<= shift;
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aExponent -= shift;
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}
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}
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else /* addition */ {
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aSignificand += bSignificand;
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// If the addition carried up, we need to right-shift the result and
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// adjust the exponent:
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if (aSignificand & implicitBit << 4) {
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const bool sticky = aSignificand & 1;
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aSignificand = aSignificand >> 1 | sticky;
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aExponent += 1;
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}
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}
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// If we have overflowed the type, return +/- infinity:
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if (aExponent >= maxExponent) return fromRep(infRep | resultSign);
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if (aExponent <= 0) {
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// Result is denormal before rounding; the exponent is zero and we
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// need to shift the significand.
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const int shift = 1 - aExponent;
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const bool sticky = aSignificand << (typeWidth - shift);
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aSignificand = aSignificand >> shift | sticky;
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aExponent = 0;
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}
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// Low three bits are round, guard, and sticky.
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const int roundGuardSticky = aSignificand & 0x7;
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// Shift the significand into place, and mask off the implicit bit.
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rep_t result = aSignificand >> 3 & significandMask;
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// Insert the exponent and sign.
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result |= (rep_t)aExponent << significandBits;
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result |= resultSign;
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// Final rounding. The result may overflow to infinity, but that is the
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// correct result in that case.
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if (roundGuardSticky > 0x4) result++;
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if (roundGuardSticky == 0x4) result += result & 1;
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return fromRep(result);
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COMPILER_RT_ABI double __adddf3(double a, double b){
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return __addXf3__(a, b);
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}
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@ -13,140 +13,10 @@
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//===----------------------------------------------------------------------===//
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#define SINGLE_PRECISION
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#include "fp_lib.h"
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#include "fp_add_impl.inc"
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ARM_EABI_FNALIAS(fadd, addsf3)
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COMPILER_RT_ABI fp_t
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__addsf3(fp_t a, fp_t b) {
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rep_t aRep = toRep(a);
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rep_t bRep = toRep(b);
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const rep_t aAbs = aRep & absMask;
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const rep_t bAbs = bRep & absMask;
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// Detect if a or b is zero, infinity, or NaN.
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if (aAbs - 1U >= infRep - 1U || bAbs - 1U >= infRep - 1U) {
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// NaN + anything = qNaN
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if (aAbs > infRep) return fromRep(toRep(a) | quietBit);
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// anything + NaN = qNaN
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if (bAbs > infRep) return fromRep(toRep(b) | quietBit);
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if (aAbs == infRep) {
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// +/-infinity + -/+infinity = qNaN
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if ((toRep(a) ^ toRep(b)) == signBit) return fromRep(qnanRep);
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// +/-infinity + anything remaining = +/- infinity
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else return a;
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}
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// anything remaining + +/-infinity = +/-infinity
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if (bAbs == infRep) return b;
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// zero + anything = anything
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if (!aAbs) {
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// but we need to get the sign right for zero + zero
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if (!bAbs) return fromRep(toRep(a) & toRep(b));
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else return b;
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}
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// anything + zero = anything
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if (!bAbs) return a;
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}
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// Swap a and b if necessary so that a has the larger absolute value.
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if (bAbs > aAbs) {
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const rep_t temp = aRep;
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aRep = bRep;
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bRep = temp;
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}
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// Extract the exponent and significand from the (possibly swapped) a and b.
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int aExponent = aRep >> significandBits & maxExponent;
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int bExponent = bRep >> significandBits & maxExponent;
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rep_t aSignificand = aRep & significandMask;
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rep_t bSignificand = bRep & significandMask;
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// Normalize any denormals, and adjust the exponent accordingly.
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if (aExponent == 0) aExponent = normalize(&aSignificand);
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if (bExponent == 0) bExponent = normalize(&bSignificand);
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// The sign of the result is the sign of the larger operand, a. If they
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// have opposite signs, we are performing a subtraction; otherwise addition.
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const rep_t resultSign = aRep & signBit;
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const bool subtraction = (aRep ^ bRep) & signBit;
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// Shift the significands to give us round, guard and sticky, and or in the
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// implicit significand bit. (If we fell through from the denormal path it
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// was already set by normalize( ), but setting it twice won't hurt
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// anything.)
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aSignificand = (aSignificand | implicitBit) << 3;
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bSignificand = (bSignificand | implicitBit) << 3;
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// Shift the significand of b by the difference in exponents, with a sticky
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// bottom bit to get rounding correct.
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const unsigned int align = aExponent - bExponent;
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if (align) {
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if (align < typeWidth) {
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const bool sticky = bSignificand << (typeWidth - align);
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bSignificand = bSignificand >> align | sticky;
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} else {
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bSignificand = 1; // sticky; b is known to be non-zero.
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}
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}
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if (subtraction) {
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aSignificand -= bSignificand;
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// If a == -b, return +zero.
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if (aSignificand == 0) return fromRep(0);
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// If partial cancellation occurred, we need to left-shift the result
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// and adjust the exponent:
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if (aSignificand < implicitBit << 3) {
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const int shift = rep_clz(aSignificand) - rep_clz(implicitBit << 3);
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aSignificand <<= shift;
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aExponent -= shift;
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}
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}
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else /* addition */ {
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aSignificand += bSignificand;
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// If the addition carried up, we need to right-shift the result and
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// adjust the exponent:
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if (aSignificand & implicitBit << 4) {
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const bool sticky = aSignificand & 1;
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aSignificand = aSignificand >> 1 | sticky;
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aExponent += 1;
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}
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}
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// If we have overflowed the type, return +/- infinity:
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if (aExponent >= maxExponent) return fromRep(infRep | resultSign);
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if (aExponent <= 0) {
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// Result is denormal before rounding; the exponent is zero and we
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// need to shift the significand.
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const int shift = 1 - aExponent;
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const bool sticky = aSignificand << (typeWidth - shift);
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aSignificand = aSignificand >> shift | sticky;
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aExponent = 0;
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}
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// Low three bits are round, guard, and sticky.
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const int roundGuardSticky = aSignificand & 0x7;
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// Shift the significand into place, and mask off the implicit bit.
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rep_t result = aSignificand >> 3 & significandMask;
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// Insert the exponent and sign.
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result |= (rep_t)aExponent << significandBits;
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result |= resultSign;
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// Final rounding. The result may overflow to infinity, but that is the
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// correct result in that case.
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if (roundGuardSticky > 0x4) result++;
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if (roundGuardSticky == 0x4) result += result & 1;
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return fromRep(result);
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COMPILER_RT_ABI float __addsf3(float a, float b) {
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return __addXf3__(a, b);
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}
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@ -0,0 +1,144 @@
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//===----- lib/fp_add_impl.inc - floaing point addition -----------*- 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 soft-float addition with the IEEE-754 default rounding
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// (to nearest, ties to even).
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//
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//===----------------------------------------------------------------------===//
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#include "fp_lib.h"
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static inline fp_t __addXf3__(fp_t a, fp_t b) {
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rep_t aRep = toRep(a);
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rep_t bRep = toRep(b);
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const rep_t aAbs = aRep & absMask;
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const rep_t bAbs = bRep & absMask;
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// Detect if a or b is zero, infinity, or NaN.
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if (aAbs - REP_C(1) >= infRep - REP_C(1) ||
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bAbs - REP_C(1) >= infRep - REP_C(1)) {
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// NaN + anything = qNaN
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if (aAbs > infRep) return fromRep(toRep(a) | quietBit);
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// anything + NaN = qNaN
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if (bAbs > infRep) return fromRep(toRep(b) | quietBit);
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if (aAbs == infRep) {
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// +/-infinity + -/+infinity = qNaN
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if ((toRep(a) ^ toRep(b)) == signBit) return fromRep(qnanRep);
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// +/-infinity + anything remaining = +/- infinity
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else return a;
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}
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// anything remaining + +/-infinity = +/-infinity
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if (bAbs == infRep) return b;
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// zero + anything = anything
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if (!aAbs) {
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// but we need to get the sign right for zero + zero
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if (!bAbs) return fromRep(toRep(a) & toRep(b));
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else return b;
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}
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// anything + zero = anything
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if (!bAbs) return a;
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}
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// Swap a and b if necessary so that a has the larger absolute value.
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if (bAbs > aAbs) {
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const rep_t temp = aRep;
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aRep = bRep;
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bRep = temp;
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}
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// Extract the exponent and significand from the (possibly swapped) a and b.
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int aExponent = aRep >> significandBits & maxExponent;
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int bExponent = bRep >> significandBits & maxExponent;
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rep_t aSignificand = aRep & significandMask;
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rep_t bSignificand = bRep & significandMask;
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// Normalize any denormals, and adjust the exponent accordingly.
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if (aExponent == 0) aExponent = normalize(&aSignificand);
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if (bExponent == 0) bExponent = normalize(&bSignificand);
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// The sign of the result is the sign of the larger operand, a. If they
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// have opposite signs, we are performing a subtraction; otherwise addition.
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const rep_t resultSign = aRep & signBit;
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const bool subtraction = (aRep ^ bRep) & signBit;
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// Shift the significands to give us round, guard and sticky, and or in the
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// implicit significand bit. (If we fell through from the denormal path it
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// was already set by normalize( ), but setting it twice won't hurt
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// anything.)
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aSignificand = (aSignificand | implicitBit) << 3;
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bSignificand = (bSignificand | implicitBit) << 3;
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// Shift the significand of b by the difference in exponents, with a sticky
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// bottom bit to get rounding correct.
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const unsigned int align = aExponent - bExponent;
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if (align) {
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if (align < typeWidth) {
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const bool sticky = bSignificand << (typeWidth - align);
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bSignificand = bSignificand >> align | sticky;
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} else {
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bSignificand = 1; // sticky; b is known to be non-zero.
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}
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}
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if (subtraction) {
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aSignificand -= bSignificand;
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// If a == -b, return +zero.
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if (aSignificand == 0) return fromRep(0);
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// If partial cancellation occured, we need to left-shift the result
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// and adjust the exponent:
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if (aSignificand < implicitBit << 3) {
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const int shift = rep_clz(aSignificand) - rep_clz(implicitBit << 3);
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aSignificand <<= shift;
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aExponent -= shift;
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}
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}
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else /* addition */ {
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aSignificand += bSignificand;
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// If the addition carried up, we need to right-shift the result and
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// adjust the exponent:
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if (aSignificand & implicitBit << 4) {
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const bool sticky = aSignificand & 1;
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aSignificand = aSignificand >> 1 | sticky;
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aExponent += 1;
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}
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}
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// If we have overflowed the type, return +/- infinity:
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if (aExponent >= maxExponent) return fromRep(infRep | resultSign);
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if (aExponent <= 0) {
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// Result is denormal before rounding; the exponent is zero and we
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// need to shift the significand.
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const int shift = 1 - aExponent;
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const bool sticky = aSignificand << (typeWidth - shift);
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aSignificand = aSignificand >> shift | sticky;
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aExponent = 0;
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}
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// Low three bits are round, guard, and sticky.
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const int roundGuardSticky = aSignificand & 0x7;
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// Shift the significand into place, and mask off the implicit bit.
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rep_t result = aSignificand >> 3 & significandMask;
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// Insert the exponent and sign.
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result |= (rep_t)aExponent << significandBits;
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result |= resultSign;
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// Final rounding. The result may overflow to infinity, but that is the
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// correct result in that case.
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if (roundGuardSticky > 0x4) result++;
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if (roundGuardSticky == 0x4) result += result & 1;
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return fromRep(result);
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}
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