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[/] [or1k/] [tags/] [nog_patch_39/] [or1ksim/] [mmu/] [dmmu.c] - Rev 102
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/* dmmu.c -- Data MMU simulation Copyright (C) 1999 Damjan Lampret, lampret@opencores.org This file is part of OpenRISC 1000 Architectural Simulator. 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; either version 2 of the License, or (at your option) any later version. 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* DMMU model (not functional yet, currently just copy of data cache). */ #include "dmmu.h" #include "abstract.h" #include "stats.h" #include "sprs.h" #include "except.h" extern int cont_run; /* Data MMU */ unsigned long dmmu_translate(unsigned long virtaddr) { unsigned long phyaddr = dmmu_simulate_tlb(virtaddr); /* printf("DMMU translate(%x) = %x\n", virtaddr, phyaddr);*/ return phyaddr; } /* Number of DTLB sets used (power of 2, max is 256) */ #define DTLB_SETS 16 /* Entry size in bytes (8 == two singlewords) */ #define DTLB_ENTRY_SIZE 8 /* Number of DTLB ways (1, 2, 3 etc., max is 4). */ #define DTLB_WAYS 2 /* Number of usage states (2, 3, 4 etc., max is 4). */ #define DTLB_USTATES 2 void dtlb_info() { if (!getsprbits(SPR_UPR, SPR_UPR_DMP)) { printf("DMMU not implemented. Set UPR[DMP].\n"); return; } printf("Data MMU %dKB: ", DTLB_SETS * DTLB_ENTRY_SIZE * DTLB_WAYS / 1024); printf("%d ways, %d sets, entry size %d bytes\n", DTLB_WAYS, DTLB_SETS, DTLB_ENTRY_SIZE); } /* First check if virtual address is covered by DTLB and if it is: - increment DTLB read hit stats, - set 'lru' at this way to DTLB_USTATES - 1 and decrement 'lru' of other ways unless they have reached 0, - check page access attributes and invoke DMMU page fault exception handler if necessary and if not: - increment DTLB read miss stats - find lru way and entry and invoke DTLB miss exception handler - set 'lru' with DTLB_USTATES - 1 and decrement 'lru' of other ways unless they have reached 0 */ void dtlb_status(int start_set) { int set; int way; int end_set = DTLB_SETS; if (!getsprbits(SPR_UPR, SPR_UPR_DMP)) { printf("DMMU not implemented. Set UPR[DMP].\n"); return; } if ((start_set >= 0) && (start_set < end_set)) end_set = start_set + 1; else start_set = 0; printf("\nDMMU: "); /* Scan set(s) and way(s). */ for (set = start_set; set < end_set; set++) { printf("\nSet %x: ", set); for (way = 0; way < DTLB_WAYS; way++) { printf(" way %d: ", way); printf("vpn=%x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_VPN)); printf("lru=%x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_LRU)); printf("pl1=%x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_PL1)); printf("v=%x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_V)); printf("a=%x ", getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_A)); printf("d=%x ", getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_D)); printf("ure=%x ", getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_URE)); printf("uwe=%x ", getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_UWE)); printf("sre=%x ", getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_SRE)); printf("swe=%x ", getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_SWE)); printf("ppn=%x ", getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_PPN)); } } printf("\n"); } unsigned long dmmu_simulate_tlb(unsigned long virtaddr) { int set, way = -1; int i; unsigned long tagaddr; unsigned long vpn; if (!(mfspr(SPR_SR) & SPR_SR_DME) || (!getsprbits(SPR_SR, SPR_SR_DME))) return virtaddr; /* Which set to check out? */ set = (virtaddr / PAGE_SIZE) % DTLB_SETS; tagaddr = (virtaddr / PAGE_SIZE) / DTLB_SETS; vpn = virtaddr / PAGE_SIZE; /* Scan all ways and try to find a matching way. */ for (i = 0; i < DTLB_WAYS; i++) if ((getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_VPN) == vpn) && getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_V)) way = i; /* Did we find our tlb entry? */ if (way >= 0) { /* Yes, we did. */ dmmu_stats.loads_tlbhit++; debug("DTLB hit (virtaddr=%x).\n", virtaddr); /* Set LRUs */ for (i = 0; i < DTLB_WAYS; i++) if (getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU)) setsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU, getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU) - 1); setsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_LRU, DTLB_USTATES - 1); return getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_PPN) * PAGE_SIZE + (virtaddr % PAGE_SIZE); } else { /* No, we didn't. */ int minlru = DTLB_USTATES - 1; int minway = 0; dmmu_stats.loads_tlbmiss++; #if 0 for (i = 0; i < DTLB_WAYS; i++) if (getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU) < minlru) minway = i; setsprbits(SPR_DTLBMR_BASE(minway) + set, SPR_DTLBMR_VPN, vpn); for (i = 0; i < DTLB_WAYS; i++) if (getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU)) setsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU, getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU) - 1); setsprbits(SPR_DTLBMR_BASE(minway) + set, SPR_DTLBMR_LRU, DTLB_USTATES - 1); setsprbits(SPR_DTLBTR_BASE(minway) + set, SPR_DTLBTR_PPN, vpn); /* 1 to 1 */ setsprbits(SPR_DTLBMR_BASE(minway) + set, SPR_DTLBMR_V, 1); #endif except_handle(EXCEPT_DTLBMISS, virtaddr); /* if tlb refill implemented in HW */ /* return getsprbits(SPR_DTLBTR_BASE(minway) + set, SPR_DTLBTR_PPN) * PAGE_SIZE + (virtaddr % PAGE_SIZE); */ return 0; } }
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