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/* dmmu.c -- data mmu simulation
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/* dmmu.c -- Data MMU simulation
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Copyright (C) 1999 Damjan Lampret, lampret@opencores.org
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Copyright (C) 1999 Damjan Lampret, lampret@opencores.org
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This file is part of OpenRISC 1000 Architectural Simulator.
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This file is part of OpenRISC 1000 Architectural Simulator.
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This program is free software; you can redistribute it and/or modify
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This program is free software; you can redistribute it and/or modify
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along with this program; if not, write to the Free Software
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* DMMU model (not functional yet, currently just copy of data cache). */
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/* DMMU model (not functional yet, currently just copy of data cache). */
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#include "dmmu.h"
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#include "dmmu.h"
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#include "abstract.h"
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#include "abstract.h"
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#include "stats.h"
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#include "stats.h"
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#include "sprs.h"
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#include "except.h"
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extern int cont_run;
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/* Data MMU */
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/* Data MMU */
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unsigned long dmmu_translate(unsigned long virtaddr)
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unsigned long dmmu_translate(unsigned long virtaddr)
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{
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{
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return virtaddr;
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unsigned long phyaddr = dmmu_simulate_tlb(virtaddr);
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printf("DMMU translate(%x) = %x\n", virtaddr, phyaddr);
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return phyaddr;
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}
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}
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/* Number of DC sets (power of 2) */
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/* Number of DTLB sets used (power of 2, max is 256) */
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#define DC_SETS 256
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#define DTLB_SETS 16
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/* Block size in bytes (1, 2, 4, 8, 16, 32 etc.) */
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/* Entry size in bytes (8 == two singlewords) */
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#define DC_BLOCK_SIZE 4
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#define DTLB_ENTRY_SIZE 8
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/* Number of DC ways (1, 2, 3 etc.). */
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/* Number of DTLB ways (1, 2, 3 etc., max is 4). */
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#define DC_WAYS 1
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#define DTLB_WAYS 2
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/* Number of usage states (2, 3, 4 etc.). */
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/* Number of usage states (2, 3, 4 etc., max is 4). */
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#define DC_USTATES 2
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#define DTLB_USTATES 2
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struct dc_set {
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struct {
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unsigned long tagaddr; /* tag address */
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int lru; /* least recently used */
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} way[DC_WAYS];
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} dc[DC_SETS];
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void xdc_info()
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/* Don't change. Defined by mask of PPN/VPN bits in TLB. */
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#define MIN_PG_SIZE 1024
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void dtlb_info()
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{
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{
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printf("Data cache %dKB: ", DC_SETS * DC_BLOCK_SIZE * DC_WAYS / 1024);
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printf("Data MMU %dKB: ", DTLB_SETS * DTLB_ENTRY_SIZE * DTLB_WAYS / 1024);
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printf("%d ways, %d sets, block size %d bytes\n", DC_WAYS, DC_SETS, DC_BLOCK_SIZE);
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printf("%d ways, %d sets, entry size %d bytes\n", DTLB_WAYS, DTLB_SETS, DTLB_ENTRY_SIZE);
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}
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}
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/* First check if data is already in the cache and if it is:
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/* First check if virtual address is covered by DTLB and if it is:
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- increment DC read hit stats,
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- increment DTLB read hit stats,
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- set 'lru' at this way to DC_USTATES - 1 and
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- set 'lru' at this way to DTLB_USTATES - 1 and
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decrement 'lru' of other ways unless they have reached 0,
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decrement 'lru' of other ways unless they have reached 0,
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- check page access attributes and invoke DMMU page fault exception
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handler if necessary
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and if not:
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and if not:
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- increment DC read miss stats
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- increment DTLB read miss stats
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- find lru way and entry and replace old tag with tag of the 'dataaddr'
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- find lru way and entry and invoke DTLB miss exception handler
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- set 'lru' with DC_USTATES - 1 and decrement 'lru' of other
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- set 'lru' with DTLB_USTATES - 1 and decrement 'lru' of other
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ways unless they have reached 0
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ways unless they have reached 0
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*/
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*/
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void xdc_simulate_read(unsigned long dataaddr)
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unsigned long dtlb_status(int start_set)
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{
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{
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int set, way = -1;
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int set;
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int i;
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int way;
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unsigned long tagaddr;
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int end_set = DTLB_SETS;
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/* Which set to check out? */
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if ((start_set >= 0) && (start_set < end_set))
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set = (dataaddr / DC_BLOCK_SIZE) % DC_SETS;
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end_set = start_set + 1;
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tagaddr = (dataaddr / DC_BLOCK_SIZE) / DC_SETS;
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else
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start_set = 0;
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/* Scan all ways and try to find a matching way. */
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for (i = 0; i < DC_WAYS; i++)
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/* Scan set(s) and way(s). */
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if (dc[set].way[i].tagaddr == tagaddr)
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for (set = start_set; set < end_set; set++) {
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way = i;
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printf("\nSet %x: ", set);
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for (way = 0; way < DTLB_WAYS; way++) {
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/* Did we find our cached data? */
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printf(" way %d: ", way);
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if (way >= 0) { /* Yes, we did. */
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printf("vpn %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_VPN));
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dc_stats.readhit++;
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printf("lru %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_LRU));
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printf("pl1 %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_PL1));
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for (i = 0; i < DC_WAYS; i++)
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printf("v %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_V));
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if (dc[set].way[i].lru)
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printf("a %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBTR_A));
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dc[set].way[i].lru--;
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printf("d %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBTR_D));
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dc[set].way[way].lru = DC_USTATES - 1;
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printf("ure %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBTR_URE));
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printf("uwe %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBTR_UWE));
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printf("sre %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBTR_SRE));
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printf("swe %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBTR_SWE));
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printf("ppn %x ", getsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBTR_PPN));
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if (way > 0)
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printf("\n");
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}
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}
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else { /* No, we didn't. */
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int minlru = DC_USTATES - 1;
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int minway = 0;
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dc_stats.readmiss++;
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for (i = 0; i < DC_WAYS; i++)
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if (dc[set].way[i].lru < minlru)
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minway = i;
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dc[set].way[minway].tagaddr = tagaddr;
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for (i = 0; i < DC_WAYS; i++)
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if (dc[set].way[i].lru)
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dc[set].way[i].lru--;
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dc[set].way[minway].lru = DC_USTATES - 1;
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}
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}
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printf("\n");
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}
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}
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/* First check if data is already in the cache and if it is:
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unsigned long dmmu_simulate_tlb(unsigned long virtaddr)
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- increment DC write hit stats,
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- set 'lru' at this way to DC_USTATES - 1 and
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decrement 'lru' of other ways unless they have reached 0,
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and if not:
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- increment DC write miss stats
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- find lru way and entry and replace old tag with tag of the 'dataaddr'
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- set 'lru' with DC_USTATES - 1 and decrement 'lru' of other
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ways unless they have reached 0
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*/
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void xdc_simulate_write(unsigned long dataaddr)
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{
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{
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int set, way = -1;
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int set, way = -1;
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int i;
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int i;
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unsigned long tagaddr;
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unsigned long tagaddr;
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unsigned long vpn;
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if (! (mfspr(SPR_SR) & SPR_SR_DME))
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return virtaddr;
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/* Which set to check out? */
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/* Which set to check out? */
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set = (dataaddr / DC_BLOCK_SIZE) % DC_SETS;
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set = (virtaddr / PAGE_SIZE) % DTLB_SETS;
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tagaddr = (dataaddr / DC_BLOCK_SIZE) / DC_SETS;
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tagaddr = (virtaddr / PAGE_SIZE) / DTLB_SETS;
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vpn = virtaddr / MIN_PG_SIZE;
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/* Scan all ways and try to find a matching way. */
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/* Scan all ways and try to find a matching way. */
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for (i = 0; i < DC_WAYS; i++)
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for (i = 0; i < DTLB_WAYS; i++)
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if (dc[set].way[i].tagaddr == tagaddr)
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if ((getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_VPN) == vpn) &&
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getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_V))
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way = i;
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way = i;
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/* Did we find our cached data? */
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/* Did we find our tlb entry? */
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if (way >= 0) { /* Yes, we did. */
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if (way >= 0) { /* Yes, we did. */
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dc_stats.writehit++;
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dmmu_stats.loads_tlbhit++;
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debug("DTLB hit (virtaddr=%x).\n", virtaddr);
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/* Set LRUs */
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for (i = 0; i < DTLB_WAYS; i++)
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if (getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU))
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setsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU, getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU) - 1);
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setsprbits(SPR_DTLBMR_BASE(way) + set, SPR_DTLBMR_LRU, DTLB_USTATES - 1);
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for (i = 0; i < DC_WAYS; i++)
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return getsprbits(SPR_DTLBTR_BASE(way) + set, SPR_DTLBTR_PPN) * MIN_PG_SIZE + (virtaddr % PAGE_SIZE);
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if (dc[set].way[i].lru)
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dc[set].way[i].lru--;
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dc[set].way[way].lru = DC_USTATES - 1;
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}
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}
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else { /* No, we didn't. */
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else { /* No, we didn't. */
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int minlru = DC_USTATES - 1;
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int minlru = DTLB_USTATES - 1;
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int minway = 0;
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int minway = 0;
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dc_stats.writemiss++;
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dmmu_stats.loads_tlbmiss++;
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#if 0
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for (i = 0; i < DC_WAYS; i++)
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for (i = 0; i < DTLB_WAYS; i++)
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if (dc[set].way[i].lru < minlru)
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if (getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU) < minlru)
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minway = i;
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minway = i;
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dc[set].way[minway].tagaddr = tagaddr;
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setsprbits(SPR_DTLBMR_BASE(minway) + set, SPR_DTLBMR_VPN, vpn);
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for (i = 0; i < DC_WAYS; i++)
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for (i = 0; i < DTLB_WAYS; i++)
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if (dc[set].way[i].lru)
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if (getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU))
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dc[set].way[i].lru--;
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setsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU, getsprbits(SPR_DTLBMR_BASE(i) + set, SPR_DTLBMR_LRU) - 1);
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dc[set].way[minway].lru = DC_USTATES - 1;
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setsprbits(SPR_DTLBMR_BASE(minway) + set, SPR_DTLBMR_LRU, DTLB_USTATES - 1);
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setsprbits(SPR_DTLBTR_BASE(minway) + set, SPR_DTLBTR_PPN, vpn); /* 1 to 1 */
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setsprbits(SPR_DTLBMR_BASE(minway) + set, SPR_DTLBMR_V, 1);
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#endif
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except_handle(EXCEPT_DTLBMISS, virtaddr);
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/* if tlb refill implemented in HW */
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/* return getsprbits(SPR_DTLBTR_BASE(minway) + set, SPR_DTLBTR_PPN) * MIN_PG_SIZE + (virtaddr % PAGE_SIZE); */
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return 0;
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}
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}
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}
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}
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No newline at end of file
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