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807 |
julius |
/*
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Test correct delay-slot exception bit (DSX) behavior on
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instruction-fetch related exceptions.
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The only case where DSX is set on instruction-fetch related
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exception is when instructions in delay slots occur in a new
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page which needs to be mapped.
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In this test we will trigger an instruction MMU miss for an
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instruction in a delay slot. To do this, we need to have a
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branch instruction as the very last instruction of a page,
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with the delay slot instruction being on a new unmapped page.
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Set r10 to hold whether we are expecting SR[DSX] to be set or
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not. Exceptions will advance the PC by 0x8 to step over both
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the jump/branch and instruction causing an exception.
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Julius Baxter
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*/
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//////////////////////////////////////////////////////////////////////
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//// ////
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//// Copyright (C) 2012 Authors and OPENCORES.ORG ////
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//// ////
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//// This source file may be used and distributed without ////
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//// restriction provided that this copyright statement is not ////
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//// removed from the file and that any derivative work contains ////
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//// the original copyright notice and the associated disclaimer. ////
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//// ////
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//// This source file is free software; you can redistribute it ////
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//// and/or modify it under the terms of the GNU Lesser General ////
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//// Public License as published by the Free Software Foundation; ////
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//// either version 2.1 of the License, or (at your option) any ////
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//// later version. ////
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//// ////
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//// This source is distributed in the hope that it will be ////
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//// useful, but WITHOUT ANY WARRANTY; without even the implied ////
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//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////
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//// PURPOSE. See the GNU Lesser General Public License for more ////
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//// details. ////
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//// ////
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//// You should have received a copy of the GNU Lesser General ////
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//// Public License along with this source; if not, download it ////
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//// from http://www.opencores.org/lgpl.shtml ////
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//// ////
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//////////////////////////////////////////////////////////////////////
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#include "spr-defs.h"
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#include "board.h"
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/* =================================================== [ exceptions ] === */
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.section .vectors, "ax"
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/* ---[ 0x100: RESET exception ]----------------------------------------- */
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.org 0x100
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l.movhi r0, 0
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/* Clear status register */
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l.ori r1, r0, SPR_SR_SM
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l.mtspr r0, r1, SPR_SR
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/* Clear timer */
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l.mtspr r0, r0, SPR_TTMR
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/* Init the stack */
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.global stack
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l.movhi r1, hi(stack)
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l.ori r1, r1, lo(stack)
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l.addi r2, r0, -3
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l.and r1, r1, r2
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/* Jump to program initialisation code */
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.global _start
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l.movhi r4, hi(_start)
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l.ori r4, r4, lo(_start)
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l.jr r4
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l.nop
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/* ---[ 0x200: BUS error ]------------------------------------------------ */
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.org 0x200
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l.j test_fail
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l.nop
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/* ---[ 0x600: ALIGN error ]------------------------------------------------ */
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.org 0x600
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l.j test_fail
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l.nop
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/* ---[ 0x700: ILLEGAL INSN exception ]------------------------------------- */
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.org 0x700
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l.j test_fail
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l.nop
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/* ---[ 0x900: DTLB exception ]--------------------------------------------- */
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.org 0x900
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l.j test_fail
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l.nop
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/* ---[ 0xa00: itlb miss ]---------------------------------------------- */
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.org 0xa00
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/* First check if we're expecting a miss in a delay slot - check r10 */
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l.mfspr r3,r0,SPR_EEAR_BASE /* Get EPC */
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l.nop 2 /* Report PC for diagnostic purpose */
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/* Check SR[DSX] was as expected */
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l.mfspr r8,r0,SPR_SR /* Get SR */
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l.andi r8,r8,SPR_SR_DSX /* Clear all bits except DSX */
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l.xor r8,r8,r10 /* r8 will be >0 if error */
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l.sfne r8,r0
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l.bf test_fail
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l.nop
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109 |
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/* Simple itlb miss handler - install 1-1 mappings on misses */
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l.mfspr r12,r0,SPR_EEAR_BASE /* Get the PC of the exception */
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l.srli r13,r12,13 /* Get the page number, divide by 8K, store in r13 */
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/* Set up the match registers */
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l.movhi r14,hi(SPR_ITLBMR_VPN)
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l.ori r14,r14,lo(SPR_ITLBMR_VPN)
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l.and r14,r12,r14 /* Mask in the VPN */
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l.ori r15,r14,SPR_ITLBMR_V /* Set this match as valid */
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/* Write it into the appropriate match register, way 0 only */
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l.mtspr r13,r15,SPR_ITLBMR_BASE(0)
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/* Set up the translate register - no restrictions */
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l.ori r15,r14,ITLB_PR_NOLIMIT
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/* Write it into the appropriate translate register */
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l.mtspr r13,r15,SPR_ITLBTR_BASE(0)
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/* MMU setup should now be complete, let's go back */
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l.rfe
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/* ---[ 0xe00: TRAP error ]------------------------------------------------ */
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.org 0xe00
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l.j test_fail
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l.nop
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/* =================================================== [ text section ] === */
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.section .text
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/* =================================================== [ start ] === */
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.global _start
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_start:
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/* First initialise the instruction MMU */
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l.mfspr r3,r0,SPR_IMMUCFGR
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l.andi r4,r3,SPR_IMMUCFGR_NTS
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l.srli r4,r4,SPR_IMMUCFGR_NTS_OFF
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l.ori r6,r0,1
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l.sll r3,r6,r4
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/* Setup the IMMU's TLBs - invalidate them */
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l.movhi r4, hi(SPR_ITLBMR_BASE(0))
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l.ori r4, r4, lo(SPR_ITLBMR_BASE(0))
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/* ITLB invalidate loop */
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1:
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l.mtspr r4, r0, 0x0
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l.addi r4, r4, 0x1
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l.sfeq r3, r0
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l.bnf 1b
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l.addi r3, r3, -1
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/* Enable MMU - we should get a miss for this page */
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l.movhi r10,0 /* Clear r10 - not expecting to be in a delay slot
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when this TLB miss occurs */
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.extern lo_immu_en
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/* Now enable the IMMU */
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l.movhi r4, hi(lo_immu_en)
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l.ori r4, r4, lo(lo_immu_en)
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l.jalr r4
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l.nop
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169 |
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/* Copy the 2 instructions from the ljr9_function function to
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places which should cause TLB misses in the delay slot */
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l.movhi r6,hi(ljr9_function)
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l.ori r6,r6,lo(ljr9_function)
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/* r13 should have the page number we're in from the TLB miss we caused
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when enabling the immu. Take that and add 16 to determine the page
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boundary we'll play with */
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l.addi r4,r13,16
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/* Calculate the physical address for this page */
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l.slli r8,r4,13
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/* Copy our function to the last 2 instructions of the page before */
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l.lwz r1,0(r6)
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l.sw -8(r8),r1
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l.lwz r1,4(r6)
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l.sw -4(r8),r1
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/* Call it - we should _not_ have DSX set on the itbl miss */
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l.movhi r10,0
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l.addi r1,r8,-8
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/* Report value */
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l.or r3,r1,r1
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l.nop 2
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l.jalr r1
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l.nop
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/* Tests finish */
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/* Now do what we've done for the miss but put delay slot instruction
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in the new page */
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/* Calculate the physical address for this page */
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l.slli r8,r4,13
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/* Copy our function to the last 2 instructions of the page before */
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l.lwz r1,0(r6)
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l.sw -4(r8),r1
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l.lwz r1,4(r6)
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l.sw 0(r8),r1
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214 |
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/* Clear insn cache for this area (need to if it's enabled so we
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don't get the cached instructions from the previous test) */
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l.mtspr r0,r8,SPR_ICBIR
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l.addi r1,r8,-4
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l.mtspr r0,r1,SPR_ICBIR
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220 |
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/* Jump to (r8-0x4) - we _should_ have DSX set on the itbl miss as
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the jump instruction will be on the last instruction of the previous
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page (already mapped in ITLB) and the delay slot will be the first
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instruction on the next page, which is unmapped at this stage and
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should cause an ITLB miss*/
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l.ori r10,r0,SPR_SR_DSX
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l.addi r1,r8,-4
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/* Report value */
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l.or r3,r1,r1
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l.nop 2
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l.jalr r1
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l.nop
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235 |
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/* TODO - track and check the number of TLB misses we should
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have incurred */
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858 |
stekern |
/* Check if IC present and skip enabling otherwise */
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l.mfspr r3,r0,SPR_UPR
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l.andi r4,r3,SPR_UPR_ICP
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l.sfeq r4,r0
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l.bf test_ok
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l.nop
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246 |
807 |
julius |
/* Now repeat the tests with caches enabled if they weren't */
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l.mfspr r1,r0,SPR_SR
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l.andi r1,r1,SPR_SR_ICE
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l.sfeq r0,r1 /* Set flag if caches not enabled */
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l.bf restart_with_caches_enabled
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l.nop
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test_ok:
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l.movhi r3,0x8000
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l.ori r3,r3,0x000d
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l.nop 2
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l.or r3,r0,r0
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l.nop 1
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test_fail:
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l.movhi r3,0xbaaa
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l.ori r3,r3,0xaaad
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l.nop 2
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l.ori r3,r0,1
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l.nop 1
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267 |
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restart_with_caches_enabled:
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268 |
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269 |
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/* Disable IMMU before restart*/
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270 |
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l.mfspr r3,r0,SPR_SR
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l.xori r3,r3,SPR_SR_IME
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l.mtspr r0,r3,SPR_ESR_BASE
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l.movhi r9,hi(.L1)
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l.ori r9,r9,lo(.L1)
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l.mtspr r0,r9,SPR_EPCR_BASE
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l.rfe
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.L1:
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l.jal _cache_init
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279 |
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l.nop
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280 |
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281 |
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/* Actually we won't want dcache enabled as we'll be reading
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282 |
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and writing instructions around the shop so will not want them
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283 |
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being cached */
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284 |
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l.mfspr r3,r0,SPR_SR
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285 |
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l.xori r3,r3,SPR_SR_DCE
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l.mtspr r0,r3,SPR_SR
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287 |
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288 |
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l.j _start
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289 |
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l.nop
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290 |
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|
291 |
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/* A simple function, which we will copy the instructions of
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292 |
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to different parts of memory */
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293 |
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ljr9_function:
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294 |
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l.jr r9
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295 |
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l.nop
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296 |
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