forked from brooke/mandel-6502
Jamey Sharp
aee587388d
This costs an extra half cycle on average, assuming uniform distribution of multiplication inputs. I don't think a half cycle is worth an extra 256-byte table.
40 lines
716 B
JavaScript
40 lines
716 B
JavaScript
function db(func) {
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let lines = [];
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for (let i = 0; i < 256; i += 16) {
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let items = [];
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for (let j = 0; j < 16; j++) {
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let x = i + j;
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items.push(func(x));
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}
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lines.push(' .byte ' + items.join(', '));
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}
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return lines.join('\n');
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}
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console.log(
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`.segment "TABLES"
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.export mul_lobyte
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.export mul_hibyte
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.export sqr_lobyte
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.export sqr_hibyte
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; (i * i) / 2 for the multiplier
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.align 256
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mul_lobyte:
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${db((i) => ((i * i) >> 1) & 0xff)}
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.align 256
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mul_hibyte:
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${db((i) => ((i * i) >> 9) & 0xff)}
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; (i * i) for the plain squares
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.align 256
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sqr_lobyte:
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${db((i) => (i * i) & 0xff)}
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.align 256
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sqr_hibyte:
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${db((i) => ((i * i) >> 8) & 0xff)}
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`);
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