Save some tokens in horrible, horrible ways. #13

2022-12-23T07:18:53Z

kistaro commented

2022-12-23 07:18:53 +00:00

Bit math can pack some of the checks you've been doing into far fewer tokens and save cycles along the way. The result is a horrific atrocity that the eyes of mortals were never meant to comprehend, but that's the entire point of Pico-8 anyway.

Bit math can pack some of the checks you've been doing into far fewer tokens _and_ save cycles along the way. The result is a horrific atrocity that the eyes of mortals were never meant to comprehend, but that's the entire point of Pico-8 anyway.

kistaro added 3 commits 2022-12-23 07:18:53 +00:00

replace comparisons with bit math bullshit fe3a68284f

integers in the range [0, 15] fit entirely in the bit mask 0x000F. integers out of that range will have at least one bit 0x0010 or higher, or will have the sign bit 0x8000 set. so to find out if one of two numbers is out of range [0, 15], we can check the bit mask of their bitwise or.

this saves tokens and cycles. it is also completely illegible. very in the spirit of Pico-8, I love it.

comment the bullshit b10447bb86

it needs it

packed crate representation 0fe3b1699f

don't bother exploding crates into four bools, and then comparing them all individually to a bunch of conditions. absurd bit manipulation bullshit saves cycles and tokens. leaving a crate's movement rule represented as four bits means we can exploit our previous calculation of dx1 and dy1, which must each either be 0x0001 or 0x8FFF, and violently hammer them down to align with this bit-packed representation, giving this glorious little atrocity.

kistaro added 1 commit 2022-12-23 08:02:11 +00:00

Fix crate math. 9d93f30426

I forgot that -1 & 1 = 1 rather than 0 so all the bit math didn't work. But I can fix it with polynomial algebra! this is much better.

pyrex approved these changes 2022-12-23 08:04:08 +00:00

kistaro added 1 commit 2022-12-23 08:18:59 +00:00

Save tokens on movemebnt checks 1995501583

I promise this is mathematically equivalent-ish to the original. (0.2 and its multiples are nonterminating decimals in base 2, so there's a little jank when the negative shift right is a shift left.)

kistaro marked the pull request as ready for review 2022-12-23 08:34:12 +00:00

kistaro added 1 commit 2022-12-23 08:34:32 +00:00

Trimming 528e67045d

Trim up redundant nil checks, sequential assignments that could be on a shared line, and repeated references to a deeply nested variable.

pyrex merged commit c480295b41 into main

2022-12-24 00:08:10 +00:00

pyrex referenced this issue from a commit

2022-12-24 00:08:10 +00:00

Save some tokens in horrible, horrible ways. (#13)

Sign in to join this conversation.

2 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: pyrex/chameleonic#13

Allow edits from maintainers