// simple.c #include #include #define sqr(x) ((x) * (x)) typedef struct { double r; double i; } complex; void interpret(complex *registers, char const *code) { complex *src, *dst; double r, i; for (; *code; code += 3) { dst = ®isters[code[2] - 'a']; src = ®isters[code[1] - 'a']; switch (*code) { case '=': dst->r = src->r; dst->i = src->i; break; case '+': dst->r += src->r; dst->i += src->i; break; case '*': r = dst->r * src->r - dst->i * src->i; i = dst->r * src->i + dst->i * src->r; dst->r = r; dst->i = i; break; default: fprintf(stderr, "undefined instruction %s (ASCII %x)\n", code, *code); exit(1); } } } int main(int argc, char **argv) { complex registers[4]; int i, x, y; char line[1600]; printf("P5\n%d %d\n%d\n", 1600, 900, 255); for (y = 0; y < 900; ++y) { for (x = 0; x < 1600; ++x) { registers[0].r = 2 * 1.6 * (x / 1600.0 - 0.5); registers[0].i = 2 * 0.9 * (y / 900.0 - 0.5); for (i = 1; i < 4; ++i) registers[i].r = registers[i].i = 0; for (i = 0; i < 256 && sqr(registers[1].r) + sqr(registers[1].i) < 4; ++i) interpret(registers, argv[1]); line[x] = i; } fwrite(line, 1, sizeof(line), stdout); } return 0; }