The fixed-point conformance cart. It exercises the 16.16 fixed-point runtime (PICO-8 semantics) and stores each result in a module global, so a test reads them straight out of RAM. Every value is bit-exact against PICO-8:
| expression | expected |
|---|---|
1.5 + 2.25 |
3.75 |
1.5 * 2.0 |
3.0 |
3.0 / 2.0 |
1.5 |
-9 \ 2 (floor div) |
-5 |
-9 % 2 (floored mod) |
1.0 |
sin(0.25) (P8 screen-space) |
-1.0 |
abs(-3.5) |
3.5 |
min(4, 7) / max(4, 7) |
4 / 7 |
function _init()
r_add = 1.5 + 2.25
r_mul = 1.5 * 2.0
r_div = 3.0 / 2.0
r_flrdiv = -9 \ 2
r_mod = -9 % 2
r_sqrt = sqrt(2.0)
r_sin = sin(0.25)
r_abs = abs(-3.5)
r_min = min(4, 7)
r_max = max(4, 7)
end
Real frame captured from the fceumm core (2x integer scale of native 256x224). The 16.16 runtime is the gtlua 6502 asm/C ported near-verbatim; verified bit-exact by reading the result globals out of RAM.
neslua build main.lua -o mathcheck.nes