Superseded / Deprecated

The feature described in this article has been superseded by a newer feature. This feature still works in PICO-8, but the new feature should be used instead. See the article's "Superseded by..." section for specific details.

shl( num, bits )

- Shifts the bits of a number to the left.

`num`-
- The number.

`bits`-
- The number of bits to shift.

The `shl()`

function takes a number and a bit count, and returns the result of shifting the bits of the number to the left by that count.

Numbers in PICO-8 are stored using a 32-bit *fixed point* format, with 16 bits for the integer portion, 16 bits for the fractional portion, and a twos complement representation for negative and positive values. Bit shifting uses the entire number representation. (See examples below.)

## Superseded by << operator[edit | edit source]

The `<<`

operator added in 0.2.0 performs the same function as `shl()`

and is now the recommended way to shift bits left, as it uses fewer tokens, costs fewer cycles at runtime, and runs on the real host CPU much more efficiently. Simply replace `shl(a,b)`

with `a<<b`

.

## Examples[edit | edit source]

```
-- 1 = 00000001 binary
-- 8 = 00001000 binary
print(shl(1, 3)) -- 8
-- 0.125 = 0000.0010 binary
-- 1.000 = 0001.0000 binary
print(shl(0.125, 3)) -- 1
print(1 << 3) -- 8, preferred method
```

## See also[edit | edit source]

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