Faster boolean +`˘ for short rows based on flattened prefix sum

This commit is contained in:
Marshall Lochbaum 2024-06-02 16:01:46 -04:00
parent 5591d0f4f0
commit bd64e8bcd2

View File

@ -343,6 +343,25 @@ B scan_rows_bit(Md1D* fd, B x) {
else si_scan_rows_or (xp, rp, n, m);
decG(x); return r;
}
if (rtid==n_add && SH(x)[1]<128) {
usz ia = IA(x); usz m = SH(x)[1];
usz bl = 128; // block size
i8 buf[bl]; i8 c = 0;
u64* xp = bitarr_ptr(x);
i8* rp; B r = m_i8arrc(&rp, x);
for (usz i = 0, j = m; i < ia; i += bl) {
usz len = ia - i; if (len > bl) len = bl;
usz e = i + len;
si_bcs8(xp + i/64, buf, len);
memset(rp+i, -c, len);
i8* bi = buf-i;
assert(j > i); for (; j < e; j += m) rp[j] = bi[j-1];
si_scan_max_init_i8(rp+i, rp+i, len, I8_MIN);
for (usz k = i; k < e; k++) rp[k] = bi[k] - rp[k];
if (j == e) { j += m; c = 0; } else c = rp[e-1];
}
decG(x); return r;
}
#endif
return bi_N;
}