pico8lib

• Index

Contents

• Fields
• Random Functions
• Miscellaneous
• Bit manipulation
• Rounding

Modules

• pico8lib.class
• pico8lib.functions
• pico8lib.graphics
• pico8lib.json
• pico8lib.log
• pico8lib.math
• pico8lib.memory
• pico8lib.number
• pico8lib.physics
• pico8lib.rational
• pico8lib.strings
• pico8lib.tables
• pico8lib.test
• pico8lib.uint32
• pico8lib.vector

Topics

• README

Examples

• snippets.p8
• test_class.p8
• test_functions.p8
• test_json.p8
• test_test.p8
• class.p8
• log.p8

Module pico8lib.number

Non-mathematical manipulation of numbers

Fields

const_number_minfrac	Smallest representable positive fraction (1/32768)
const_number_maxint	Maximum representable positive integer (32767)
const_number_maxnum	Maximum representable positive number (32767 + 32767/32768)
const_number_minnum	Minimum representable negative integer and number (-32768)

Random Functions

rand (x)	Random value [0 to x-1] such as pixel or grid offsets
randi (x)	Random value [0 to x] such as pixels in/on a rect
randp (x)	Random value [1 to x-1] such as pixels in a rect
randpi (x)	Random value [1 to x] such as lua list indices
randb (n, x)	Random value [n to x-1]
randbi (n, x)	Random value [n to x-1]
randfrac (n, x)	Random value [n to x] for non-integer n and x

Miscellaneous

popcount_loop (n)	Count the 1 bits in a number This version runs one loop per set bit, 26 tokens
popcount_magic (v)	Count the 1 bits in a number This version runs in constant time, 42 tokens Constant time is 111% the one-set-bit time of the shorter loop function

Bit manipulation

rotr8 (n, b)	Rotate an 8-bit integer n to the right by b bits
rotl8 (n, b)	Rotate an 8-bit integer n to the left by b bits

Rounding

flrceil (x, d)	Floor or Ceiling of a number
tozero (n)	Round toward zero
toinf (n)	Round toward infinity
round (n)	Round to nearest integer, 0.5 rounds toward +Inf

Fields

const_number_minfrac

Smallest representable positive fraction (1/32768)

const_number_maxint

Maximum representable positive integer (32767)

const_number_maxnum

Maximum representable positive number (32767 + 32767/32768)

const_number_minnum

Minimum representable negative integer and number (-32768)

Random Functions

rand (x)

Random value [0 to x-1] such as pixel or grid offsets

Parameters:

• x

randi (x)

Random value [0 to x] such as pixels in/on a rect

Parameters:

• x

randp (x)

Random value [1 to x-1] such as pixels in a rect

Parameters:

• x

randpi (x)

Random value [1 to x] such as lua list indices

Parameters:

• x

randb (n, x)

Random value [n to x-1]

Parameters:

• n
• x

randbi (n, x)

Random value [n to x-1]

Parameters:

• n
• x (n to x]

randfrac (n, x)

Random value [n to x] for non-integer n and x

Parameters:

• n
• x

Miscellaneous

popcount_loop (n)

Count the 1 bits in a number This version runs one loop per set bit, 26 tokens

Parameters:

• n algorithm from https //graphics.stanford.edu/~seander/bithacks.html

popcount_magic (v)

Count the 1 bits in a number This version runs in constant time, 42 tokens Constant time is 111% the one-set-bit time of the shorter loop function

Parameters:

• v original implementation from https //www.lexaloffle.com/bbs/?pid=72850 [2020-02-06 16:25] felice: if i post code in a bbs post then it's free for all to use. credit is nice of course if it's significant. algorithm from https://support.amd.com/techdocs/25112.pdf or https://graphics.stanford.edu/~seander/bithacks.html

Bit manipulation

rotr8 (n, b)

Rotate an 8-bit integer n to the right by b bits

Parameters:

• n
• b

rotl8 (n, b)

Rotate an 8-bit integer n to the left by b bits

Parameters:

• n
• b

Rounding

flrceil (x, d)

Floor or Ceiling of a number

Parameters:

• x number The number to floor or ceiling
• d number 1 for floor, -1 for ceiling

Returns:

number The floor'd or ceiling'd number

tozero (n)

Round toward zero

Parameters:

• n

toinf (n)

Round toward infinity

Parameters:

• n

round (n)

Round to nearest integer, 0.5 rounds toward +Inf

Parameters:

• n