- Shifts the bits of a number to the left.
- The number.
- The number of bits to shift.
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Superseded by 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
<< 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
-- 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