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type
Int128* = object
udata: array[4,uint32]
template sdata(arg: Int128, idx: int): int32 =
# udata and sdata was supposed to be in a union, but unions are
# handled incorrectly in the VM.
cast[ptr int32](arg.udata[idx].unsafeAddr)[]
# encoding least significant int first (like LittleEndian)
type
InvalidArgument = object of Exception
template require(cond: bool) =
if unlikely(not cond):
raise newException(InvalidArgument, "")
const
Zero* = Int128(udata: [0'u32,0,0,0])
One* = Int128(udata: [1'u32,0,0,0])
Ten* = Int128(udata: [10'u32,0,0,0])
Min = Int128(udata: [0'u32,0,0,0x80000000'u32])
Max = Int128(udata: [high(uint32),high(uint32),high(uint32),uint32(high(int32))])
template low*(t: typedesc[Int128]): Int128 = Min
template high*(t: typedesc[Int128]): Int128 = Max
proc `$`*(a: Int128): string
proc toInt128*[T: SomeInteger](arg: T): Int128 =
when T is SomeUnsignedInt:
when sizeof(arg) <= 4:
result.udata[0] = uint32(arg)
else:
result.udata[0] = uint32(arg and T(0xffffffff))
result.udata[1] = uint32(arg shr 32)
else:
when sizeof(arg) <= 4:
result.sdata(0) = int32(arg)
if arg < 0: # sign extend
result.sdata(1) = -1
result.sdata(2) = -1
result.sdata(3) = -1
else:
let tmp = int64(arg)
result.udata[0] = uint32(tmp and 0xffffffff)
result.sdata(1) = int32(tmp shr 32)
if arg < 0: # sign extend
result.sdata(2) = -1
result.sdata(3) = -1
template isNegative(arg: Int128): bool =
arg.sdata(3) < 0
template isNegative(arg: int32): bool =
arg < 0
proc bitconcat(a,b: uint32): uint64 =
(uint64(a) shl 32) or uint64(b)
proc bitsplit(a: uint64): (uint32,uint32) =
(cast[uint32](a shr 32), cast[uint32](a))
proc toInt64*(arg: Int128): int64 =
if isNegative(arg):
assert(arg.sdata(3) == -1, "out of range")
assert(arg.sdata(2) == -1, "out of range")
else:
assert(arg.sdata(3) == 0, "out of range")
assert(arg.sdata(2) == 0, "out of range")
cast[int64](bitconcat(arg.udata[1], arg.udata[0]))
proc toUInt64*(arg: Int128): uint64 =
assert(arg.udata[3] == 0)
assert(arg.udata[2] == 0)
bitconcat(arg.udata[1], arg.udata[0])
proc addToHex(result: var string; arg: uint32) =
for i in 0 ..< 8:
let idx = (arg shr ((7-i) * 4)) and 0xf
result.add "0123456789abcdef"[idx]
proc addToHex*(result: var string; arg: Int128) =
var i = 3
while i >= 0:
result.addToHex(arg.udata[i])
i -= 1
proc toHex*(arg: Int128): string =
result.addToHex(arg)
proc inc*(a: var Int128, y: uint32 = 1) =
let input = a
a.udata[0] += y
if unlikely(a.udata[0] < y):
a.udata[1].inc
if unlikely(a.udata[1] == 0):
a.udata[2].inc
if unlikely(a.udata[2] == 0):
a.udata[3].inc
doAssert(a.sdata(3) != low(int32), "overflow")
proc cmp*(a,b: Int128): int =
let tmp1 = cmp(a.sdata(3), b.sdata(3))
if tmp1 != 0: return tmp1
let tmp2 = cmp(a.udata[2], b.udata[2])
if tmp2 != 0: return tmp2
let tmp3 = cmp(a.udata[1], b.udata[1])
if tmp3 != 0: return tmp3
let tmp4 = cmp(a.udata[0], b.udata[0])
return tmp4
proc `<`*(a,b: Int128): bool =
cmp(a,b) < 0
proc `<=`*(a,b: Int128): bool =
cmp(a,b) <= 0
proc `==`*(a,b: Int128): bool =
if a.udata[0] != b.udata[0]: return false
if a.udata[1] != b.udata[1]: return false
if a.udata[2] != b.udata[2]: return false
if a.udata[3] != b.udata[3]: return false
return true
proc inplaceBitnot(a: var Int128) =
a.udata[0] = not a.udata[0]
a.udata[1] = not a.udata[1]
a.udata[2] = not a.udata[2]
a.udata[3] = not a.udata[3]
proc bitnot*(a: Int128): Int128 =
result.udata[0] = not a.udata[0]
result.udata[1] = not a.udata[1]
result.udata[2] = not a.udata[2]
result.udata[3] = not a.udata[3]
proc bitand*(a,b: Int128): Int128 =
result.udata[0] = a.udata[0] and b.udata[0]
result.udata[1] = a.udata[1] and b.udata[1]
result.udata[2] = a.udata[2] and b.udata[2]
result.udata[3] = a.udata[3] and b.udata[3]
proc bitor*(a,b: Int128): Int128 =
result.udata[0] = a.udata[0] or b.udata[0]
result.udata[1] = a.udata[1] or b.udata[1]
result.udata[2] = a.udata[2] or b.udata[2]
result.udata[3] = a.udata[3] or b.udata[3]
proc bitxor*(a,b: Int128): Int128 =
result.udata[0] = a.udata[0] xor b.udata[0]
result.udata[1] = a.udata[1] xor b.udata[1]
result.udata[2] = a.udata[2] xor b.udata[2]
result.udata[3] = a.udata[3] xor b.udata[3]
proc `shr`*(a: Int128, b: int): Int128 =
let b = b and 127
if b < 32:
result.sdata(3) = a.sdata(3) shr b
result.udata[2] = cast[uint32](bitconcat(a.udata[3], a.udata[2]) shr b)
result.udata[1] = cast[uint32](bitconcat(a.udata[2], a.udata[1]) shr b)
result.udata[0] = cast[uint32](bitconcat(a.udata[1], a.udata[0]) shr b)
elif b < 64:
if isNegative(a):
result.sdata(3) = -1
result.sdata(2) = a.sdata(3) shr (b and 31)
result.udata[1] = cast[uint32](bitconcat(a.udata[2], a.udata[1]) shr (b and 31))
result.udata[0] = cast[uint32](bitconcat(a.udata[1], a.udata[0]) shr (b and 31))
elif b < 96:
if isNegative(a):
result.sdata(3) = -1
result.sdata(2) = -1
result.sdata(1) = a.sdata(3) shr (b and 31)
result.udata[0] = cast[uint32](bitconcat(a.udata[1], a.udata[0]) shr (b and 31))
else: # b < 128
if isNegative(a):
result.sdata(3) = -1
result.sdata(2) = -1
result.sdata(1) = -1
result.sdata(0) = a.sdata(3) shr (b and 31)
proc `shl`*(a: Int128, b: int): Int128 =
let b = b and 127
if b < 32:
result.udata[0] = a.udata[0] shl b
result.udata[1] = cast[uint32]((bitconcat(a.udata[1], a.udata[0]) shl b) shr 32)
result.udata[2] = cast[uint32]((bitconcat(a.udata[2], a.udata[1]) shl b) shr 32)
result.udata[3] = cast[uint32]((bitconcat(a.udata[3], a.udata[2]) shl b) shr 32)
elif b < 64:
result.udata[0] = 0
result.udata[1] = a.udata[0] shl (b and 31)
result.udata[2] = cast[uint32]((bitconcat(a.udata[1], a.udata[0]) shl (b and 31)) shr 32)
result.udata[3] = cast[uint32]((bitconcat(a.udata[2], a.udata[1]) shl (b and 31)) shr 32)
elif b < 96:
result.udata[0] = 0
result.udata[1] = 0
result.udata[2] = a.udata[0] shl (b and 31)
result.udata[3] = cast[uint32]((bitconcat(a.udata[1], a.udata[0]) shl (b and 31)) shr 32)
else:
result.udata[0] = 0
result.udata[1] = 0
result.udata[2] = 0
result.udata[3] = a.udata[0] shl (b and 31)
proc `+`*(a,b: Int128): Int128 =
let tmp0 = uint64(a.udata[0]) + uint64(b.udata[0])
result.udata[0] = cast[uint32](tmp0)
let tmp1 = uint64(a.udata[1]) + uint64(b.udata[1]) + (tmp0 shr 32)
result.udata[1] = cast[uint32](tmp1)
let tmp2 = uint64(a.udata[2]) + uint64(b.udata[2]) + (tmp1 shr 32)
result.udata[2] = cast[uint32](tmp2)
let tmp3 = uint64(a.udata[3]) + uint64(b.udata[3]) + (tmp2 shr 32)
result.udata[3] = cast[uint32](tmp3)
proc `+=`*(a: var Int128, b: Int128) =
a = a + b
proc `-`*(a: Int128): Int128 =
result = bitnot(a)
result.inc
proc `-`*(a,b: Int128): Int128 =
a + (-b)
proc `-=`*(a: var Int128, b: Int128) =
a = a - b
proc abs*(a: Int128): Int128 =
if isNegative(a):
-a
else:
a
proc abs(a: int32): int =
if a < 0: -a else: a
proc `*`(a: Int128, b: uint32): Int128 =
let tmp0 = uint64(a.udata[0]) * uint64(b)
let tmp1 = uint64(a.udata[1]) * uint64(b)
let tmp2 = uint64(a.udata[2]) * uint64(b)
let tmp3 = uint64(a.udata[3]) * uint64(b)
if unlikely(tmp3 > uint64(high(int32))):
assert(false, "overflow")
result.udata[0] = cast[uint32](tmp0)
result.udata[1] = cast[uint32](tmp1) + cast[uint32](tmp0 shr 32)
result.udata[2] = cast[uint32](tmp2) + cast[uint32](tmp1 shr 32)
result.udata[3] = cast[uint32](tmp3) + cast[uint32](tmp2 shr 32)
proc `*`*(a: Int128, b: int32): Int128 =
let isNegative = isNegative(a) xor isNegative(b)
result = a * cast[uint32](abs(b))
if b < 0:
result = -result
proc `*=`*(a: var Int128, b: int32): Int128 =
result = result * b
proc makeint128(high,low: uint64): Int128 =
result.udata[0] = cast[uint32](low)
result.udata[1] = cast[uint32](low shr 32)
result.udata[2] = cast[uint32](high)
result.udata[3] = cast[uint32](high shr 32)
proc high64(a: Int128): uint64 =
bitconcat(a.udata[3], a.udata[2])
proc low64(a: Int128): uint64 =
bitconcat(a.udata[1], a.udata[0])
proc `*`*(lhs,rhs: Int128): Int128 =
let isNegative = isNegative(lhs) xor isNegative(rhs)
let
a = cast[uint64](lhs.udata[0])
b = cast[uint64](lhs.udata[1])
c = cast[uint64](lhs.udata[2])
d = cast[uint64](lhs.udata[3])
e = cast[uint64](rhs.udata[0])
f = cast[uint64](rhs.udata[1])
g = cast[uint64](rhs.udata[2])
h = cast[uint64](rhs.udata[3])
let a32 = cast[uint64](lhs.udata[1])
let a00 = cast[uint64](lhs.udata[0])
let b32 = cast[uint64](rhs.udata[1])
let b00 = cast[uint64](rhs.udata[0])
result = makeInt128(high64(lhs) * low64(rhs) + low64(lhs) * high64(rhs) + a32 * b32, a00 * b00)
result = result + toInt128(a32 * b00) shl 32
result = result + toint128(a00 * b32) shl 32
if isNegative != isNegative(result):
echo result
assert(false, "overflow")
proc `*=`*(a: var Int128, b: Int128) =
a = a * b
import bitops
proc fastLog2*(a: Int128): int =
if a.udata[3] != 0:
return 96 + fastLog2(a.udata[3])
if a.udata[2] != 0:
return 64 + fastLog2(a.udata[2])
if a.udata[1] != 0:
return 32 + fastLog2(a.udata[1])
if a.udata[0] != 0:
return fastLog2(a.udata[0])
proc divMod*(dividend, divisor: Int128): tuple[quotient, remainder: Int128] =
assert(divisor != Zero)
let isNegative = isNegative(dividend) xor isNegative(divisor)
var dividend = abs(dividend)
let divisor = abs(divisor)
if divisor > dividend:
result.quotient = Zero
result.remainder = dividend
return
if divisor == dividend:
result.quotient = One
result.remainder = Zero
return
var denominator = divisor
var quotient = Zero
# Left aligns the MSB of the denominator and the dividend.
let shift = fastLog2(dividend) - fastLog2(denominator)
denominator = denominator shl shift
# Uses shift-subtract algorithm to divide dividend by denominator. The
# remainder will be left in dividend.
for i in 0 .. shift:
quotient = quotient shl 1
if dividend >= denominator:
dividend = dividend - denominator
quotient = bitor(quotient, One)
denominator = denominator shr 1
result.quotient = quotient
result.remainder = dividend
proc `div`*(a,b: Int128): Int128 =
let (a,b) = divMod(a,b)
return a
proc `mod`*(a,b: Int128): Int128 =
let (a,b) = divMod(a,b)
return b
proc `$`*(a: Int128): string =
if a == Zero:
result = "0"
elif a == low(Int128):
result = "-170141183460469231731687303715884105728"
else:
let isNegative = isNegative(a)
var a = abs(a)
while a > Zero:
let (quot, rem) = divMod(a, Ten)
result.add "0123456789"[rem.toInt64]
a = quot
if isNegative:
result.add '-'
var i = 0
var j = high(result)
while i < j:
swap(result[i], result[j])
i += 1
j -= 1
proc parseDecimalInt128*(arg: string, pos: int = 0): Int128 =
assert(pos < arg.len)
assert(arg[pos] in {'-','0'..'9'})
var isNegative = false
var pos = pos
if arg[pos] == '-':
isNegative = true
pos += 1
result = Zero
while pos < arg.len and arg[pos] in '0' .. '9':
result = result * Ten
result.inc(uint32(arg[pos]) - uint32('0'))
pos += 1
if isNegative:
result = -result
# fluff
proc `<`*(a: Int128, b: BiggestInt): bool =
cmp(a,toInt128(b)) < 0
proc `<`*(a: BiggestInt, b: Int128): bool =
cmp(toInt128(a), b) < 0
proc `<=`*(a: Int128, b: BiggestInt): bool =
cmp(a,toInt128(b)) <= 0
proc `<=`*(a: BiggestInt, b: Int128): bool =
cmp(toInt128(a), b) <= 0
proc `==`*(a: Int128, b: BiggestInt): bool =
a == toInt128(b)
proc `==`*(a: BiggestInt, b: Int128): bool =
toInt128(a) == b
proc `-`*(a: BiggestInt, b: Int128): Int128 =
toInt128(a) - b
proc `-`*(a: Int128, b: BiggestInt): Int128 =
a - toInt128(b)
proc `+`*(a: BiggestInt, b: Int128): Int128 =
toInt128(a) + b
proc `+`*(a: Int128, b: BiggestInt): Int128 =
a + toInt128(b)
when isMainModule:
let (a,b) = divMod(Ten,Ten)
doAssert $One == "1"
doAssert $Ten == "10"
doAssert $Zero == "0"
let c = parseDecimalInt128("12345678989876543210123456789")
doAssert $c == "12345678989876543210123456789"
var d : array[39, Int128]
d[0] = parseDecimalInt128("1")
d[1] = parseDecimalInt128("10")
d[2] = parseDecimalInt128("100")
d[3] = parseDecimalInt128("1000")
d[4] = parseDecimalInt128("10000")
d[5] = parseDecimalInt128("100000")
d[6] = parseDecimalInt128("1000000")
d[7] = parseDecimalInt128("10000000")
d[8] = parseDecimalInt128("100000000")
d[9] = parseDecimalInt128("1000000000")
d[10] = parseDecimalInt128("10000000000")
d[11] = parseDecimalInt128("100000000000")
d[12] = parseDecimalInt128("1000000000000")
d[13] = parseDecimalInt128("10000000000000")
d[14] = parseDecimalInt128("100000000000000")
d[15] = parseDecimalInt128("1000000000000000")
d[16] = parseDecimalInt128("10000000000000000")
d[17] = parseDecimalInt128("100000000000000000")
d[18] = parseDecimalInt128("1000000000000000000")
d[19] = parseDecimalInt128("10000000000000000000")
d[20] = parseDecimalInt128("100000000000000000000")
d[21] = parseDecimalInt128("1000000000000000000000")
d[22] = parseDecimalInt128("10000000000000000000000")
d[23] = parseDecimalInt128("100000000000000000000000")
d[24] = parseDecimalInt128("1000000000000000000000000")
d[25] = parseDecimalInt128("10000000000000000000000000")
d[26] = parseDecimalInt128("100000000000000000000000000")
d[27] = parseDecimalInt128("1000000000000000000000000000")
d[28] = parseDecimalInt128("10000000000000000000000000000")
d[29] = parseDecimalInt128("100000000000000000000000000000")
d[30] = parseDecimalInt128("1000000000000000000000000000000")
d[31] = parseDecimalInt128("10000000000000000000000000000000")
d[32] = parseDecimalInt128("100000000000000000000000000000000")
d[33] = parseDecimalInt128("1000000000000000000000000000000000")
d[34] = parseDecimalInt128("10000000000000000000000000000000000")
d[35] = parseDecimalInt128("100000000000000000000000000000000000")
d[36] = parseDecimalInt128("1000000000000000000000000000000000000")
d[37] = parseDecimalInt128("10000000000000000000000000000000000000")
d[38] = parseDecimalInt128("100000000000000000000000000000000000000")
for i in 0 ..< d.len:
for j in 0 ..< d.len:
doAssert(cmp(d[i], d[j]) == cmp(i,j))
if i + j < d.len:
doAssert d[i] * d[j] == d[i+j]
if i - j >= 0:
doAssert d[i] div d[j] == d[i-j]
var sum: Int128
for it in d:
sum += it
doAssert $sum == "111111111111111111111111111111111111111"
for it in d.mitems:
it = -it
for i in 0 ..< d.len:
for j in 0 ..< d.len:
doAssert(cmp(d[i], d[j]) == -cmp(i,j))
if i + j < d.len:
doAssert d[i] * d[j] == -d[i+j]
if i - j >= 0:
doAssert d[i] div d[j] == -d[i-j]
doAssert $high(Int128) == "170141183460469231731687303715884105727"
doAssert $low(Int128) == "-170141183460469231731687303715884105728"
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