2000/0921/bitsy/mmu.c (diff list | history)

2000/0920/sys/src/9/bitsy/mmu.c:91,104 – 2000/0921/sys/src/9/bitsy/mmu.c:91,111 (short | long | prev | next)
2000/0907		} /*
2000/0920		* map special use space
2000/0921		* map special space, assume that the space isn't already mapped
2000/0907		*/ ulong*
2000/0909		mapspecial(ulong physaddr, int len)
2000/0907		{ ulong *t;
2000/0909		ulong virtaddr, i;
2000/0921		ulong virtaddr, i, base, end, off, entry, candidate;
2000/0907
2000/0921		base = physaddr & ~(BY2PG-1); end = (physaddr+len-1) & ~(BY2PG-1); if(len > 128*1024) usemeg = 1; off = 0; candidate = 0;
2000/0907		/* first see if we've mapped it somewhere, the first hole means we're done */
2000/0909		for(virtaddr = REGZERO; virtaddr < REGTOP; virtaddr += OneMeg){ if((l1table[virtaddr>>20] & L1TypeMask) != L1PageTable){
2000/0920/sys/src/9/bitsy/mmu.c:105,118 – 2000/0921/sys/src/9/bitsy/mmu.c:112,145
2000/0907		/* create a page table and break */ t = xspanalloc(BY2PG, 1024, 0); memzero(t, BY2PG, 0);
2000/0909		l1table[virtaddr>>20] = L1PageTable | L1Domain0 | (((ulong)t) & L1PTBaseMask);
2000/0921		l1table[virtaddr>>20] = L1PageTable | L1Domain0 | (((ulong)t) & L1PTBaseMask);
2000/0907		break; }
2000/0909		t = (ulong*)(l1table[virtaddr>>20] & L1PTBaseMask);
2000/0907		for(i = 0; i < OneMeg; i += BY2PG){
2000/0920		if((t[(virtaddr+i)>>20] & L2TypeMask) != L2SmallPage)
2000/0921		entry = t[(virtaddr+i)>>20]; /* first hole means nothing left, add map */ if((entry & L2TypeMask) != L2SmallPage)
2000/0907		break;
2000/0920
2000/0921		if(candidate == 0){ /* look for start of range */ if((entry & L2PageBaseMask) != base) continue; candidate = virtaddr+i; } else { /* look for contiunued range */ if((entry & L2PageBaseMask) != base + off) candidate = 0; continue; } } /* if we're at the end of the range, area is already mapped */ if((entry & L2PageBaseMask) == end) return candidate + (physaddr-base);
2000/0907		} if(i < OneMeg){
2000/0909		virtaddr += i;