more bitshifting and benchmark changes

This commit is contained in:
Joseph Montanaro 2021-07-15 14:56:17 -07:00
parent e9c6b615a1
commit 2165511624
2 changed files with 125 additions and 44 deletions

View File

@ -1,6 +1,10 @@
import bitops, strutils
proc show(i: SomeInteger, bitlength = 16) =
echo BiggestInt(i).toBin(bitlength)
type
Color = enum
cRed, cGreen, cBlue, cYellow, cPurple
@ -12,14 +16,29 @@ type
const
masks = [
0'u16,
7,
63,
511,
4095,
0'u16, # dummy value just to get the indices right
0b0_000_000_000_000_111,
0b0_000_000_000_111_111,
0b0_000_000_111_111_111,
0b0_000_111_111_111_111,
0b0_111_111_111_111_111,
]
template offset(s: ColorStack, idx: Natural): uint8 =
# Compute the bit offset for a given index.
# Dependent on the stack's length.
(s.len - 1 - cast[uint8](idx)) * 3
# items are stored from left to right but right-aligned, so we
# need to shift right to access anything other than the last
template offset(s: ColorStack, idx: BackwardsIndex): uint8 =
# for backwards index, we are still shifting right but
# the lower the index the less we have to shift
(cast[uint8](idx) - 1) * 3
proc add(s: var ColorStack, c: Color) =
# e.g. if stack is 0b0000000000000100:
# and color is 0b00000011
@ -27,34 +46,65 @@ proc add(s: var ColorStack, c: Color) =
# bitor: 0b0000000000100000 and 0b00000011
# results in 0b0000000000100011
s.data = (s.data shl 3).bitor(cast[uint8](c))
echo BiggestInt(s.data).toBin(16)
inc s.len
proc high(s: ColorStack): uint8 = s.len - 1
proc low(s: ColorStack): uint8 = 0 # just... always 0, I guess
proc `[]`(s: ColorStack, i: uint8 | BackwardsIndex): Color =
# shift, then mask everything but the three rightmost bits
result = cast[Color](
(s.data shr s.offset(i)) and masks[1]
)
proc `[]=`(s: var ColorStack, i: uint8 | BackwardsIndex, c: Color) =
let offset = s.offset(i)
s.data = (s.data and bitnot(masks[1] shl offset)) or (cast[uint16](c) shl offset)
iterator items(s: ColorStack): Color =
# s.len is unsigned so it will wrap around if it's 0
# but that's no problem, we can just no-op if len is 0
if s.len != 0:
for i in countdown(s.len - 1, 0'u8):
yield cast[Color]((s.data shr (i * 3)) and masks[1])
iterator pairs(s: ColorStack): (int, Color) =
var count = 0
for color in s:
yield (count, color)
inc count
proc moveSubstack(src, dst: var ColorStack, nToMove: uint8) =
# Moves a sub-stack from the top of src to the top of dst
# shift the dst stack by the length of the substack to make room
let shift = nToMove * 3
dst.data = dst.data shl shift
# then we mask the source data to present only the items
# being moved, and AND that with the shifted dst data
dst.data = bitor(
bitand(src.data, masks[src.len]),
dst.data
)
# being moved, and OR that with the shifted dst data
dst.data = dst.data or (src.data and masks[src.len])
dst.len += nToMove
# then we shift the source to get rid of the moved items
src.data = src.data shr shift
src.len -= nToMove
iterator items(s: ColorStack): Color =
for offset in countdown(s.len - 1, 0'u8):
let shifted = s.data shr offset
echo shifted
echo bitand(shifted, masks[0])
yield Color(bitand(shifted, masks[0]))
# yield s.data shr i * 3 |> bitand(masks[0]) |> Color
# :(
proc moveSubstackPre(src, dst: var ColorStack, nToMove: uint8) =
# Moves a sub-stack from the top of src to the bottom of dst
# shift src stack to position substack above its destination,
# get rid of everything to the left of the substack,
# and OR that with the existing dst data
dst.data = dst.data or ( (src.data shl (dst.len * 3)) and masks[src.len])
dst.len += nToMove
# get rid of the substack we just moved
src.data = src.data shr (nToMove * 3)
src.len -= nToMove
proc `$`(s: ColorStack): string =
@ -69,14 +119,30 @@ proc `$`(s: ColorStack): string =
var one: ColorStack
one.add(cGreen)
one.add(cBlue)
one.add(cYellow)
# one.add(cPurple)
# one.add(cRed)
var two: ColorStack
two.add(cPurple)
# two.add(cPurple)
two.add(cRed)
two.add(cYellow)
# two.add(cYellow)
echo "one: ", one
# echo "two: ", two
echo "two: ", two
one[^2] = cPurple
echo "one: ", one
# echo "one 0: ", one[0]
# echo "one 2: ", one[2]
# echo "one 3: ", one[3]
# echo "one ^1: ", one[^1]
# echo "one ^2: ", one[^2]
# echo "one ^4: ", one[^4]
# echo "<move>"
# moveSubstack(one, two, 2)
# echo two
# echo "one: ", one
# echo "two: ", two

View File

@ -1,7 +1,32 @@
import math, random, strformat, times
import math, random, strformat, times, std/monotimes
import fixedseq, game, simulation, ui
type
TestResults = object
ops: int
time: Duration
proc summarize(tr: TestResults) =
let secs = tr.time.inMilliseconds.float / 1000
stdout.write("Test completed:\n")
stdout.write(" " & $tr.ops, " operations in " & $round(secs, 2) & " seconds\n")
stdout.write(" " & $round(tr.ops.float / secs, 2) & " operations per second")
stdout.flushFile()
template executionTime(body: untyped): Duration =
let start = getMonoTime()
body
getMonoTime() - start
proc getRand(): Rand =
randomize()
result = initRand(rand(int64))
proc randomDice(r: var Rand): seq[tuple[c: Color, p: int]] =
for c in Color:
let v = r.rand(1..3)
@ -18,18 +43,15 @@ proc newRandomGame(r: var Rand): Board =
result.setState(dice, [])
proc testGames(n: SomeInteger = 100): auto =
var r = initRand(rand(int64))
let dice = randomDice(r)
var b: Board
b.init
b.setState(dice, [])
b.display(1, 5)
let startTime = cpuTime()
let scores = b.randomGames(n)
result = cpuTime() - startTime
scores.display()
proc games(nTests, nSamples: SomeInteger): TestResults =
var r = getRand()
var scores: ScoreSet
for i in 1 .. nTests:
let b = newRandomGame(r)
let dur = executionTime:
let s = b.randomGames(nSamples)
result.ops += s.sum()
result.time += dur
proc testLegs(n: Natural = 100): auto =
@ -72,14 +94,7 @@ proc testSpread(nTests, nSamples: Natural) =
when isMainModule:
randomize()
var r = initRand(rand(int64))
let b = newRandomGame(r)
b.display(1, 5)
echo b.showSpaces(1, 16)
let scores = b.getLegScores
echo scores.showPercents
games(100, 1_000_000).summarize()
# let start_states = 2_000
# let executionTime = testLegs(start_states)
# echo "Execution time: ", executionTime