This is a maintenance fork
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

139 lines
4.7 KiB

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "tool/build/emubin/poke.h"
#include "tool/build/emubin/real.h"
#include "tool/build/emubin/realstart.inc"
#define signbit(x) __builtin_signbit(x)
static const unsigned char kBlocks[] = {
[0b1111] = 0xdb, // █
[0b0110] = 0xdb, // █
[0b1001] = 0xdb, // █
[0b0111] = 0xdb, // █
[0b1011] = 0xdb, // █
[0b1110] = 0xdb, // █
[0b1101] = 0xdb, // █
[0b1100] = 0xdc, // ▄
[0b0100] = 0xdc, // ▄
[0b1000] = 0xdc, // ▄
[0b0101] = 0xdd, // ▌
[0b1010] = 0xde, // ▐
[0b0011] = 0xdf, // ▀
[0b0010] = 0xdf, // ▀
[0b0001] = 0xdf, // ▀
};
forceinline void *memset(void *di, int al, unsigned long cx) {
asm("rep stosb"
: "=D"(di), "=c"(cx), "=m"(*(char(*)[cx])di)
: "0"(di), "1"(cx), "a"(al));
return di;
}
forceinline long double pi(void) {
long double x;
asm("fldpi" : "=t"(x));
return x;
}
forceinline long double tau(void) {
return pi() * 2;
}
forceinline void sincosl(long double x, long double *sin, long double *cos) {
asm("fsincos" : "=t"(*sin), "=u"(*cos) : "0"(x));
}
forceinline long double atan2l(long double x, long double y) {
asm("fpatan" : "+t"(x) : "u"(y) : "st(1)");
return x;
}
forceinline long lrintl(long double x) {
long i;
asm("fistp%z0\t%0" : "=m"(i) : "t"(x) : "st");
return i;
}
forceinline long double truncl(long double x) {
asm("frndint" : "+t"(x));
return x;
}
forceinline long double fabsl(long double x) {
asm("fabs" : "+t"(x));
return x;
}
forceinline long lroundl(long double x) {
int s = signbit(x);
x = truncl(fabsl(x) + .5);
if (s) x = -x;
return lrintl(x);
}
static unsigned short GetFpuControlWord(void) {
unsigned short cw;
asm("fnstcw\t%0" : "=m"(cw));
return cw;
}
static void SetFpuControlWord(unsigned short cw) {
asm volatile("fldcw\t%0" : /* no outputs */ : "m"(cw));
}
static void InitializeFpu(void) {
asm("fninit");
}
static void SetTruncationRounding(void) {
SetFpuControlWord(GetFpuControlWord() | 0x0c00);
}
static void spiral(unsigned char p[25][80][2], unsigned char B[25][80], int g) {
int i, x, y;
long double a, b, u, v, h;
for (a = b = i = 0; i < 1000; ++i) {
sincosl(a, &u, &v);
h = atan2l(u, v) - .333L * g;
x = lroundl(80 + u * b);
y = lroundl(25 + v * b * (1. / ((266 / 64.) * (900 / 1600.))));
B[y >> 1][x >> 1] |= 1 << ((y & 1) << 1 | (x & 1));
POKE(p[y >> 1][x >> 1][0], kBlocks[B[y >> 1][x >> 1]]);
POKE(p[y >> 1][x >> 1][1], (lrintl((h + tau()) * (8 / tau())) & 7) + 8);
a += .05;
b += .05;
}
}
int main() {
int g;
InitializeFpu();
SetTruncationRounding();
SetVideoMode(3);
for (g = 0;; ++g) {
SetEs(0);
memset((void *)(0x7c00 + 512), 0, 25 * 80);
SetEs(0xb8000 >> 4);
memset((void *)0, 0, 25 * 80 * 2);
spiral((void *)0, (void *)(0x7c00 + 512), g);
}
}