Adds long division emulation

This commit is contained in:
konsoletyper 2013-12-09 21:45:47 +04:00
parent bb7053cfa4
commit d948d8d8b0

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@ -307,14 +307,21 @@ Long_sub = function(a, b) {
(hilo & 0xFFFF) | ((hihi & 0xFFFF) << 16));
}
Long_compare = function(a, b) {
var r = a.hi - a.hi;
if (r != 0) {
var r = a.hi - b.hi;
if (r !== 0) {
return r;
}
return a.lo - b.lo;
var r = (a.lo >>> 1) - (b.lo >>> 1);
if (r !== 0) {
return r;
}
return (a.lo & 1) - (b.lo & 1);
}
Long_isPositive = function(a) {
return (a.hi & 0x80000000) === 0;
}
Long_isNegative = function(a) {
return a.hi < 0;
return (a.hi & 0x80000000) !== 0;
}
Long_mul = function(a, b) {
var a_lolo = a.lo & 0xFFFF;
@ -329,18 +336,35 @@ Long_mul = function(a, b) {
var lolo = (a_lolo * b_lolo) | 0;
var lohi = (a_lohi * b_lolo + a_lolo * b_lohi + (lolo >> 16)) | 0;
var hilo = (a_hilo * b_lolo + a_lohi * b_lohi + a_lolo * b_hilo + (lohi >> 16)) | 0;
var hihi = (a_hihi * b_lolo + a_hilo * b_lohi + a_lohi * b_hilo + a_lolo * b_hihi +
(hilo >> 16)) | 0;
return new Long((lolo & 0xFFFF) | ((lohi & 0xFFFF) << 16),
(hilo & 0xFFFF) | ((hihi & 0xFFFF) << 16));
var hihi = (a_hihi * b_lolo + a_hilo * b_lohi + a_lohi * b_hilo + a_lolo * b_hihi + (hilo >> 16)) | 0;
return new Long((lolo & 0xFFFF) | ((lohi & 0xFFFF) << 16), (hilo & 0xFFFF) | ((hihi & 0xFFFF) << 16));
}
Long_div = function(a, b) {
var result = (a.hi * 0x100000000 + a.lo) / (b.hi * 0x100000000 + b.lo);
return new Long(result | 0, (result / 0x100000000) | 0);
return Long_divRem(a, b)[0];
}
Long_rem = function(a, b) {
var result = (a.hi * 0x100000000 + a.lo) % (b.hi * 0x100000000 + b.lo);
return new Long(result | 0, (result / 0x100000000) | 0);
return Long_divRem(a, b)[1];
}
Long_divRem = function(a, b) {
var positive = Long_isNegative(a) === Long_isNegative(b);
if (Long_isNegative(a)) {
a = Long_neg(a);
}
if (Long_isNegative(b)) {
b = Long_neg(b);
}
a = new LongInt(a.lo, a.hi, 0);
b = new LongInt(b.lo, b.hi, 0);
var q = LongInt_div(a, b);
a = new Long(a.lo, a.hi);
q = new Long(q.lo, q.hi);
return positive ? [q, a] : [Long_neg(q), Long_neg(a)];
}
Long_shiftLeft16 = function(a) {
return new Long(a.lo << 16, (a.lo >>> 16) | (a.hi << 16));
}
Long_shiftRight16 = function(a) {
return new Long((a.lo >>> 16) | (a.hi << 16), a.hi >>> 16);
}
Long_and = function(a, b) {
return new Long(a.lo & b.lo, a.hi & b.hi);
@ -371,4 +395,168 @@ Long_shru = function(a, b) {
} else {
return new Long((a.hi >>> (b - 32)), 0);
}
}
// Represents a mutable 80-bit unsigned integer
LongInt = function(lo, hi, sup) {
this.lo = lo;
this.hi = hi;
this.sup = sup;
}
LongInt_mul = function(a, b) {
var a_lolo = ((a.lo & 0xFFFF) * b) | 0;
var a_lohi = ((a.lo >>> 16) * b) | 0;
var a_hilo = ((a.hi & 0xFFFF) * b) | 0;
var a_hihi = ((a.hi >>> 16) * b) | 0;
var sup = (a.sup * b) | 0;
a_lohi = (a_lohi + (a_lolo >> 16)) | 0;
a_hilo = (a_hilo + (a_lohi >> 16)) | 0;
a_hihi = (a_hihi + (a_hilo >> 16)) | 0;
sup = (sup + (a_hihi >> 16)) | 0;
a.lo = (a_lolo & 0xFFFF) | (a_lohi << 16);
a.hi = (a_hilo & 0xFFFF) | (a_hihi << 16);
a.sup = sup & 0xFFFF;
}
LongInt_sub = function(a, b) {
var a_lolo = a.lo & 0xFFFF;
var a_lohi = a.lo >>> 16;
var a_hilo = a.hi & 0xFFFF;
var a_hihi = a.hi >>> 16;
var b_lolo = b.lo & 0xFFFF;
var b_lohi = b.lo >>> 16;
var b_hilo = b.hi & 0xFFFF;
var b_hihi = b.hi >>> 16;
a_lolo = (a_lolo - b_lolo) | 0;
a_lohi = (a_lohi - b_lohi + (a_lolo >> 16)) | 0;
a_hilo = (a_hilo - b_hilo + (a_lohi >> 16)) | 0;
a_hihi = (a_hihi - b_hihi + (a_hilo >> 16)) | 0;
sup = (a.sup - b.sup + (a_hihi >> 16)) | 0;
a.lo = (a_lolo & 0xFFFF) | ((a_lohi & 0xFFFF) << 16);
a.hi = (a_hilo & 0xFFFF) | ((a_hihi & 0xFFFF) << 16);
a.sup = sup;
}
LongInt_add = function(a, b) {
var a_lolo = a.lo & 0xFFFF;
var a_lohi = a.lo >>> 16;
var a_hilo = a.hi & 0xFFFF;
var a_hihi = a.hi >>> 16;
var b_lolo = b.lo & 0xFFFF;
var b_lohi = b.lo >>> 16;
var b_hilo = b.hi & 0xFFFF;
var b_hihi = b.hi >>> 16;
a_lolo = (a_lolo + b_lolo) | 0;
a_lohi = (a_lohi + b_lohi + (a_lolo >> 16)) | 0;
a_hilo = (a_hilo + b_hilo + (a_lohi >> 16)) | 0;
a_hihi = (a_hihi + b_hihi + (a_hilo >> 16)) | 0;
sup = (a.sup + b.sup + (a_hihi >> 16)) | 0;
a.lo = (a_lolo & 0xFFFF) | (a_lohi << 16);
a.hi = (a_hilo & 0xFFFF) | (a_hihi << 16);
a.sup = sup;
}
LongInt_ucompare = function(a, b) {
var r = (a.sup - b.sup);
if (r != 0) {
return r;
}
var r = (a.hi >>> 1) - (b.hi >>> 1);
if (r != 0) {
return r;
}
var r = (a.hi & 1) - (b.hi & 1);
if (r != 0) {
return r;
}
var r = (a.lo >>> 1) - (b.lo >>> 1);
if (r != 0) {
return r;
}
return (a.lo & 1) - (b.lo & 1);
}
LongInt_numOfLeadingZeroBits = function(a) {
var n = 0;
var d = 16;
while (d > 0) {
if ((a >>> d) !== 0) {
a >>>= d;
n = (n + d) | 0;
}
d = (d / 2) | 0;
}
return 31 - n;
}
LongInt_shl = function(a, b) {
if (b < 32) {
a.sup = ((a.hi >>> (32 - b)) | (a.sup << b)) & 0xFFFF;
a.hi = (a.lo >>> (32 - b)) | (a.hi << b);
a.lo <<= b;
} else if (b < 64) {
a.sup = ((a.lo >>> (64 - b)) | (a.hi << (b - 32))) & 0xFFFF;
a.hi = a.lo << b;
a.lo = 0;
} else {
a.sup = (a.lo << (b - 64)) & 0xFFFF;
a.hi = 0;
a.lo = 0;
}
}
LongInt_shr = function(a, b) {
if (b < 32) {
a.lo = (a.lo >>> b) | (a.hi << (32 - b));
a.hi = (a.hi >>> b) | (a.sup << (32 - b));
a.sup >>>= b;
} else if (b < 64) {
a.lo = (a.hi >>> (b - 32)) | (a.sup << (64 - b));
a.hi = a.sup >>> (b - 32);
a.sup = 0;
} else {
a.lo = a.sup >>> (b - 64);
a.hi = 0;
a.sup = 0;
}
}
LongInt_copy = function(a) {
return new LongInt(a.lo, a.hi, a.sup);
}
LongInt_div = function(a, b) {
// Normalize divisor
var bits = b.hi !== 0 ? LongInt_numOfLeadingZeroBits(b.hi) : LongInt_numOfLeadingZeroBits(b.lo) + 32;
var sz = 1 + ((bits / 16) | 0);
var dividentBits = bits % 16;
LongInt_shl(b, bits);
LongInt_shl(a, dividentBits);
q = new LongInt(0, 0, 0);
while (sz-- > 0) {
LongInt_shl(q, 16);
// Calculate approximate q
var digitA = (a.hi >>> 16) + (0x10000 * a.sup);
var digitB = b.hi >>> 16;
var digit = (digitA / digitB) | 0;
var t = LongInt_copy(b);
LongInt_mul(t, digit);
// Adjust q either down or up
if (LongInt_ucompare(t, a) >= 0) {
while (LongInt_ucompare(t, a) > 0) {
LongInt_sub(t, b);
q = (q - 1) | 0;
}
} else {
while (true) {
var nextT = LongInt_copy(t);
LongInt_add(nextT, b);
if (LongInt_ucompare(nextT, a) > 0) {
break;
}
t = nextT;
q = (q + 1) | 0;
}
}
LongInt_sub(a, t);
q.lo |= digit;
LongInt_shl(a, 16);
}
LongInt_shr(a, bits + 16);
return q;
}