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author | mid-kid <esteve.varela@gmail.com> | 2018-04-04 22:26:07 +0200 |
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committer | mid-kid <esteve.varela@gmail.com> | 2018-04-04 22:26:07 +0200 |
commit | d3cc861d334c8b773c1b6c662ed9924c43cef009 (patch) | |
tree | 0e8df3581a081f77167785502c093fbfc5535d73 /engine/math/get_square_root.asm | |
parent | 81fff9bb80af3db0ee381c824261b8963e1cc221 (diff) |
Fix snake_case filenames
Renamed a bunch of files, most of them one-off functions, to better fit
the general snake_case naming scheme. Also renamed some awfully long filenames.
Diffstat (limited to 'engine/math/get_square_root.asm')
-rw-r--r-- | engine/math/get_square_root.asm | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/engine/math/get_square_root.asm b/engine/math/get_square_root.asm new file mode 100644 index 000000000..412fd04ff --- /dev/null +++ b/engine/math/get_square_root.asm @@ -0,0 +1,32 @@ +NUM_SQUARE_ROOTS EQU 255 + +GetSquareRoot: ; 13b87 +; Return the square root of de in b. + +; Rather than calculating the result, we take the index of the +; first value in a table of squares that isn't lower than de. + + ld hl, .Squares + ld b, 0 +.loop +; Make sure we don't go past the end of the table. + inc b + ld a, b + cp NUM_SQUARE_ROOTS + ret z + +; Iterate over the table until b**2 >= de. + ld a, [hli] + sub e + ld a, [hli] + sbc d + + jr c, .loop + ret + +.Squares: ; 13b98 +x = 1 +rept NUM_SQUARE_ROOTS + dw x * x +x = x + 1 +endr |