brooke/mandel-6502
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whee

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This commit is contained in:
Brooke Vibber 2023-01-07 22:57:18 -08:00
parent a47836a39a
commit 8044dbfc21
2 changed files with 27 additions and 17 deletions
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18
fixed.js
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@ -4,18 +4,19 @@ let bits = 16;
// max Mandelbrot zx/zy addition range prior to checking distance
let inputRange = 4;
// Room to hold power up to -12/+4 for 16-bit mandelbrot
let shift = 4;
let base = 2 ** (bits - shift);
//let reduction = 4;
let reduction = 0;
let roundOffset = (2 ** (reduction - 1)) + 1;
// Room to hold power up to -12/+4 for 16-bit mandelbrot
let shift = 5;
let base = 2 ** (bits - shift);
let entries = 2 ** (bits - reduction);
let bytes = Math.ceil(bits / 8) * entries;
// try to keep all but the last few bits semi-accurate
let epsilonBits = 1 ;
let epsilonBits = 1;
let epsilon = 2 ** epsilonBits;
export function toFixed(float) {
@ -147,8 +148,6 @@ deltaCount = 0;
console.log('done');
console.log(`size of enloggen table: ${entries} entries, ${bytes} bytes`);
console.log(`size of empower table: ${entries * 2} entries, ${bytes * 2} bytes`);
let m = 0;
for (let i = 0; i < enloggen.length; i++) {
@ -157,3 +156,6 @@ for (let i = 0; i < enloggen.length; i++) {
console.log(`max enloggen entry is ${m}`);
*/
console.log(`size of enloggen table: ${entries} entries, ${bytes} bytes`);
console.log(`size of empower table: ${entries * 2} entries, ${bytes * 2} bytes`);

24
sim.js
View file

@ -1,5 +1,13 @@
import {toFixed, toFloat, mul} from './fixed.js';
import {toFixed, mul} from './fixed.js';
let toFixedLog = toFixed;
function toFixed16(val) {
// 4.12
return Math.round(val * (2 ** 12))
}
let four16 = toFixed16(4);
function imul(a, b) {
return Math.imul(a, b) >> 12;
@ -25,7 +33,7 @@ function logmul(a, b) {
return product;
}
let four = toFixed(4);
let fourLog = toFixedLog(4);
let max = 256;
let width = 256;
@ -146,8 +154,8 @@ function run() {
});
setup('imul', (cx, cy) => {
cx = toFixed(cx);
cy = toFixed(cy);
cx = toFixed16(cx);
cy = toFixed16(cy);
let zx = 0;
let zy = 0;
let zx_2 = 0;
@ -159,7 +167,7 @@ function run() {
zx_2 = imul(zx, zx);
zy_2 = imul(zy, zy);
zx_zy = imul(zx, zy);
if (zx_2 + zy_2 >= four) {
if (zx_2 + zy_2 >= four16) {
return i;
}
}
@ -169,8 +177,8 @@ function run() {
});
setup('log', (cx, cy) => {
cx = toFixed(cx);
cy = toFixed(cy);
cx = toFixedLog(cx);
cy = toFixedLog(cy);
let zx = 0;
let zy = 0;
let zx_2 = 0;
@ -182,7 +190,7 @@ function run() {
zx_2 = logmul(zx, zx);
zy_2 = logmul(zy, zy);
zx_zy = logmul(zx, zy);
if (zx_2 + zy_2 >= four) {
if (zx_2 + zy_2 >= fourLog) {
return i;
}
}