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+#if defined(R4000)
+
+// TITLE("Cache Flush")
+//++
+//
+// Copyright (c) 1991 Microsoft Corporation
+//
+// Module Name:
+//
+// j4cache.s
+//
+// Abstract:
+//
+// This module implements the code necessary for cache operations on
+// a MIPS R4000.
+//
+// Author:
+//
+// David N. Cutler (davec) 19-Dec-1991
+//
+// Environment:
+//
+// Kernel mode only.
+//
+// Revision History:
+//
+//--
+
+#include "halmips.h"
+
+//
+// Define cache operations constants.
+//
+
+#define COLOR_BITS (7 << PAGE_SHIFT) // color bit (R4000 - 8kb cache)
+#define COLOR_MASK (0x7fff) // color mask (R4000 - 8kb cache)
+#define FLUSH_BASE 0xfffe0000 // flush base address
+#define PROTECTION_BITS ((1 << ENTRYLO_V) | (1 << ENTRYLO_D)) //
+
+ SBTTL("Change Color Page")
+//++
+//
+// VOID
+// HalChangeColorPage (
+// IN PVOID NewColor,
+// IN PVOID OldColor,
+// IN ULONG PageFrame
+// )
+//
+// Routine Description:
+//
+// This function changes the color of a page if the old and new colors
+// do not match.
+//
+// The algorithm used to change colors for a page is as follows:
+//
+// 1. Purge (hit/invalidate) the page from the instruction cache
+// using the old color.
+//
+// 2. Purge (hit/invalidate) the page from the data cache using
+// the old color.
+//
+// Arguments:
+//
+// NewColor (a0) - Supplies the page aligned virtual address of the
+// new color of the page to change.
+//
+// OldColor (a1) - Supplies the page aligned virtual address of the
+// old color of the page to change.
+//
+// PageFrame (a2) - Supplies the page frame number of the page that
+// is changed.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ .struct 0
+ .space 3 * 4 // fill
+CpRa: .space 4 // saved return address
+CpFrameLength: // length of stack frame
+CpA0: .space 4 // (a0)
+CpA1: .space 4 // (a1)
+CpA2: .space 4 // (a2)
+CpA3: .space 4 // (a3)
+
+ NESTED_ENTRY(HalChangeColorPage, CpFrameLength, zero)
+
+ subu sp,sp,CpFrameLength // allocate stack frame
+ sw ra,CpRa(sp) // save return address
+
+ PROLOGUE_END
+
+ and a0,a0,COLOR_BITS // isolate new color bits
+ and a1,a1,COLOR_BITS // isolate old color bits
+ beq a0,a1,10f // if eq, colors match
+ sw a1,CpA1(sp) // save old color bits
+ sw a2,CpA2(sp) // save page frame
+
+//
+// Purge the instruction cache using the old page color.
+//
+
+ move a0,a1 // set color value
+ move a1,a2 // set page frame number
+ li a2,PAGE_SIZE // set length of purge
+ jal HalPurgeIcachePage // purge instruction cache page
+
+//
+// Flush the data cache using the old page color.
+//
+
+ lw a0,CpA1(sp) // get old color bits
+ lw a1,CpA2(sp) // get page frame number
+ li a2,PAGE_SIZE // set length of purge
+ jal HalFlushDcachePage // purge data cache page
+10: lw ra,CpRa(sp) // get return address
+ addu sp,sp,CpFrameLength // deallocate stack frame
+ j ra // return
+
+ .end HalChangeColorPage
+
+ SBTTL("Flush Data Cache Page")
+//++
+//
+// VOID
+// HalFlushDcachePage (
+// IN PVOID Color,
+// IN ULONG PageFrame,
+// IN ULONG Length
+// )
+//
+// Routine Description:
+//
+// This function flushes (hit/writeback/invalidate) up to a page of data
+// from the data cache.
+//
+// Arguments:
+//
+// Color (a0) - Supplies the starting virtual address and color of the
+// data that is flushed.
+//
+// PageFrame (a1) - Supplies the page frame number of the page that
+// is flushed.
+//
+// Length (a2) - Supplies the length of the region in the page that is
+// flushed.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ LEAF_ENTRY(HalFlushDcachePage)
+
+#if DBG
+
+ lw t0,KeDcacheFlushCount // get address of dcache flush count
+ lw t1,0(t0) // increment the count of flushes
+ addu t1,t1,1 //
+ sw t1,0(t0) // store result
+
+#endif
+
+ .set noreorder
+ .set noat
+ lw v0,KiPcr + PcAlignedCachePolicy(zero) // get cache policy
+ and a0,a0,COLOR_MASK // isolate color and offset bits
+ li t0,FLUSH_BASE // get base flush address
+ or t0,t0,a0 // compute color virtual address
+ sll t1,a1,ENTRYLO_PFN // shift page frame into position
+ or t1,t1,PROTECTION_BITS // merge protection bits
+ or t1,t1,v0 // merge cache policy
+ and a0,a0,0x1000 // isolate TB entry index
+ beql zero,a0,10f // if eq, first entry
+ move t2,zero // set second page table entry
+ move t2,t1 // set second page table entry
+ move t1,zero // set first page table entry
+10: mfc0 t3,wired // get TB entry index
+ lw v0,KiPcr + PcSecondLevelDcacheFillSize(zero) // get 2nd fill size
+ lw t4,KiPcr + PcFirstLevelDcacheFillSize(zero) // get 1st fill size
+ bnel zero,v0,15f // if ne, second level cache present
+ move t4,v0 // set flush block size
+ .set at
+ .set reorder
+
+//
+// Flush a page from the data cache.
+//
+
+15: DISABLE_INTERRUPTS(t5) // disable interrupts
+
+ .set noreorder
+ .set noat
+ mfc0 t6,entryhi // get current PID and VPN2
+ srl t7,t0,ENTRYHI_VPN2 // isolate VPN2 of virtual address
+ sll t7,t7,ENTRYHI_VPN2 //
+ and t6,t6,0xff << ENTRYHI_PID // isolate current PID
+ or t7,t7,t6 // merge PID with VPN2 of virtual address
+ mtc0 t7,entryhi // set VPN2 and PID for probe
+ mtc0 t1,entrylo0 // set first PTE value
+ mtc0 t2,entrylo1 // set second PTE value
+ mtc0 t3,index // set TB index value
+ nop // fill
+ tlbwi // write TB entry - 3 cycle hazzard
+ subu t6,t4,1 // compute block size minus one
+ and t7,t0,t6 // compute offset in block
+ addu a2,a2,t6 // round up to next block
+ addu a2,a2,t7 //
+ nor t6,t6,zero // complement block size minus one
+ and a2,a2,t6 // truncate length to even number
+ beq zero,a2,30f // if eq, no blocks to flush
+ and t8,t0,t6 // compute starting virtual address
+ addu t9,t8,a2 // compute ending virtual address
+ bne zero,v0,40f // if ne, second level cache present
+ subu t9,t9,t4 // compute ending loop address
+
+//
+// Flush the primary data cache only.
+//
+
+20: cache HIT_WRITEBACK_INVALIDATE_D,0(t8) // invalidate cache block
+ bne t8,t9,20b // if ne, more blocks to invalidate
+ addu t8,t8,t4 // compute next block address
+ .set at
+ .set reorder
+
+30: ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ j ra // return
+
+//
+// Flush the primary and secondary data caches.
+//
+
+ .set noreorder
+ .set noat
+40: cache HIT_WRITEBACK_INVALIDATE_SD,0(t8) // invalidate cache block
+ bne t8,t9,40b // if ne, more blocks to invalidate
+ addu t8,t8,t4 // compute next block address
+ .set at
+ .set reorder
+
+ ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ j ra // return
+
+ .end HalFlushDcachePage
+
+ SBTTL("Purge Data Cache Page")
+//++
+//
+// VOID
+// HalPurgeDcachePage (
+// IN PVOID Color,
+// IN ULONG PageFrame,
+// IN ULONG Length
+// )
+//
+// Routine Description:
+//
+// This function purges (hit/invalidate) up to a page of data from the
+// data cache.
+//
+// Arguments:
+//
+// Color (a0) - Supplies the starting virtual address and color of the
+// data that is purged.
+//
+// PageFrame (a1) - Supplies the page frame number of the page that
+// is purged.
+//
+// Length (a2) - Supplies the length of the region in the page that is
+// purged.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ LEAF_ENTRY(HalPurgeDcachePage)
+
+#if DBG
+
+ lw t0,KeDcacheFlushCount // get address of dcache flush count
+ lw t1,0(t0) // increment the count of flushes
+ addu t1,t1,1 //
+ sw t1,0(t0) // store result
+
+#endif
+
+ .set noreorder
+ .set noat
+ lw v0,KiPcr + PcAlignedCachePolicy(zero) // get cache policy
+ and a0,a0,COLOR_MASK // isolate color bits
+ li t0,FLUSH_BASE // get base flush address
+ or t0,t0,a0 // compute color virtual address
+ sll t1,a1,ENTRYLO_PFN // shift page frame into position
+ or t1,t1,PROTECTION_BITS // merge protection bits
+ or t1,t1,v0 // merge cache policy
+ and a0,a0,0x1000 // isolate TB entry index
+ beql zero,a0,10f // if eq, first entry
+ move t2,zero // set second page table entry
+ move t2,t1 // set second page table entry
+ move t1,zero // set first page table entry
+10: mfc0 t3,wired // get TB entry index
+ lw v0,KiPcr + PcSecondLevelDcacheFillSize(zero) // get 2nd fill size
+ lw t4,KiPcr + PcFirstLevelDcacheFillSize(zero) // get 1st fill size
+ bnel zero,v0,15f // if ne, second level cache present
+ move t4,v0 // set purge block size
+ .set at
+ .set reorder
+
+//
+// Purge data from the data cache.
+//
+
+15: DISABLE_INTERRUPTS(t5) // disable interrupts
+
+ .set noreorder
+ .set noat
+ mfc0 t6,entryhi // get current PID and VPN2
+ srl t7,t0,ENTRYHI_VPN2 // isolate VPN2 of virtual address
+ sll t7,t7,ENTRYHI_VPN2 //
+ and t6,t6,0xff << ENTRYHI_PID // isolate current PID
+ or t7,t7,t6 // merge PID with VPN2 of virtual address
+ mtc0 t7,entryhi // set VPN2 and PID for probe
+ mtc0 t1,entrylo0 // set first PTE value
+ mtc0 t2,entrylo1 // set second PTE value
+ mtc0 t3,index // set TB index value
+ nop // fill
+ tlbwi // write TB entry - 3 cycle hazzard
+ subu t6,t4,1 // compute block size minus one
+ and t7,t0,t6 // compute offset in block
+ addu a2,a2,t6 // round up to next block
+ addu a2,a2,t7 //
+ nor t6,t6,zero // complement block size minus one
+ and a2,a2,t6 // truncate length to even number
+ beq zero,a2,30f // if eq, no blocks to purge
+ and t8,t0,t6 // compute starting virtual address
+ addu t9,t8,a2 // compute ending virtual address
+ bne zero,v0,40f // if ne, second level cache present
+ subu t9,t9,t4 // compute ending loop address
+
+//
+// Purge the primary data cache only.
+//
+
+20: cache HIT_INVALIDATE_D,0(t8) // invalidate cache block
+ bne t8,t9,20b // if ne, more blocks to invalidate
+ addu t8,t8,t4 // compute next block address
+ .set at
+ .set reorder
+
+30: ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ j ra // return
+
+//
+// Purge the primary and secondary data caches.
+//
+
+ .set noreorder
+ .set noat
+40: cache HIT_INVALIDATE_SD,0(t8) // invalidate cache block
+ bne t8,t9,40b // if ne, more blocks to invalidate
+ addu t8,t8,t4 // compute next block address
+ .set at
+ .set reorder
+
+ ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ j ra // return
+
+ .end HalPurgeDcachePage
+
+ SBTTL("Purge Instruction Cache Page")
+//++
+//
+// VOID
+// HalPurgeIcachePage (
+// IN PVOID Color,
+// IN ULONG PageFrame,
+// IN ULONG Length
+// )
+//
+// Routine Description:
+//
+// This function purges (hit/invalidate) up to a page fo data from the
+// instruction cache.
+//
+// Arguments:
+//
+// Color (a0) - Supplies the starting virtual address and color of the
+// data that is purged.
+//
+// PageFrame (a1) - Supplies the page frame number of the page that
+// is purged.
+//
+// Length (a2) - Supplies the length of the region in the page that is
+// purged.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ LEAF_ENTRY(HalPurgeIcachePage)
+
+#if DBG
+
+ lw t0,KeIcacheFlushCount // get address of icache flush count
+ lw t1,0(t0) // increment the count of flushes
+ addu t1,t1,1 //
+ sw t1,0(t0) // store result
+
+#endif
+
+ .set noreorder
+ .set noat
+ lw v0,KiPcr + PcAlignedCachePolicy(zero) // get cache policy
+ and a0,a0,COLOR_MASK // isolate color bits
+ li t0,FLUSH_BASE // get base flush address
+ or t0,t0,a0 // compute color virtual address
+ sll t1,a1,ENTRYLO_PFN // shift page frame into position
+ or t1,t1,PROTECTION_BITS // merge protection bits
+ or t1,t1,v0 // merge cache policy
+ and a0,a0,0x1000 // isolate TB entry index
+ beql zero,a0,10f // if eq, first entry
+ move t2,zero // set second page table entry
+ move t2,t1 // set second page table entry
+ move t1,zero // set first page table entry
+10: mfc0 t3,wired // get TB entry index
+ lw v0,KiPcr + PcSecondLevelIcacheFillSize(zero) // get 2nd fill size
+ lw t4,KiPcr + PcFirstLevelIcacheFillSize(zero) // get 1st fill size
+ bnel zero,v0,15f // if ne, second level cache present
+ move t4,v0 // set purge block size
+ .set at
+ .set reorder
+
+//
+// Purge data from the instruction cache.
+//
+
+15: DISABLE_INTERRUPTS(t5) // disable interrupts
+
+ .set noreorder
+ .set noat
+ mfc0 t6,entryhi // get current PID and VPN2
+ srl t7,t0,ENTRYHI_VPN2 // isolate VPN2 of virtual address
+ sll t7,t7,ENTRYHI_VPN2 //
+ and t6,t6,0xff << ENTRYHI_PID // isolate current PID
+ or t7,t7,t6 // merge PID with VPN2 of virtual address
+ mtc0 t7,entryhi // set VPN2 and PID for probe
+ mtc0 t1,entrylo0 // set first PTE value
+ mtc0 t2,entrylo1 // set second PTE value
+ mtc0 t3,index // set TB index value
+ nop // fill
+ tlbwi // write TB entry - 3 cycle hazzard
+ subu t6,t4,1 // compute block size minus one
+ and t7,t0,t6 // compute offset in block
+ addu a2,a2,t6 // round up to next block
+ addu a2,a2,t7 //
+ nor t6,t6,zero // complement block size minus one
+ and a2,a2,t6 // truncate length to even number
+ beq zero,a2,30f // if eq, no blocks to purge
+ and t8,t0,t6 // compute starting virtual address
+ addu t9,t8,a2 // compute ending virtual address
+ bne zero,v0,40f // if ne, second level cache present
+ subu t9,t9,t4 // compute ending loop address
+
+//
+// Purge the primary instruction cache only.
+//
+
+20: cache HIT_INVALIDATE_I,0(t8) // invalidate cache block
+ bne t8,t9,20b // if ne, more blocks to invalidate
+ addu t8,t8,t4 // compute next block address
+ .set at
+ .set reorder
+
+30: ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ j ra // return
+
+//
+// Purge the primary and secondary instruction caches.
+//
+
+ .set noreorder
+ .set noat
+40: cache HIT_INVALIDATE_SI,0(t8) // invalidate cache block
+ bne t8,t9,40b // if ne, more blocks to invalidate
+ addu t8,t8,t4 // compute next block address
+ .set at
+ .set reorder
+
+ ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ j ra // return
+
+ .end HalPurgeIcachePage
+
+ SBTTL("Sweep Data Cache")
+//++
+//
+// VOID
+// HalSweepDcache (
+// VOID
+// )
+//
+// Routine Description:
+//
+// This function sweeps (index/writeback/invalidate) the entire data cache.
+//
+// Arguments:
+//
+// None.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ LEAF_ENTRY(HalSweepDcache)
+
+#if DBG
+
+ lw t0,KeDcacheFlushCount // get address of dcache flush count
+ lw t1,0(t0) // increment the count of flushes
+ addu t1,t1,1 //
+ sw t1,0(t0) // store result
+
+#endif
+
+ lw t0,KiPcr + PcFirstLevelDcacheSize(zero) // get data cache size
+ lw t1,KiPcr + PcFirstLevelDcacheFillSize(zero) // get block size
+ li a0,KSEG0_BASE // set starting index value
+ addu a1,a0,t0 // compute ending cache address
+ subu a1,a1,t1 // compute ending block address
+
+//
+// Sweep the primary data cache.
+//
+
+ .set noreorder
+ .set noat
+10: cache INDEX_WRITEBACK_INVALIDATE_D,0(a0) // writeback/invalidate on index
+ bne a0,a1,10b // if ne, more to invalidate
+ addu a0,a0,t1 // compute address of next block
+ .set at
+ .set reorder
+
+ lw t0,KiPcr + PcSecondLevelDcacheSize(zero) // get data cache size
+ lw t1,KiPcr + PcSecondLevelDcacheFillSize(zero) // get block size
+ beq zero,t1,30f // if eq, no second level cache
+ li a0,KSEG0_BASE // set starting index value
+ addu a1,a0,t0 // compute ending cache address
+ subu a1,a1,t1 // compute ending block address
+
+//
+// Sweep the secondary data cache.
+//
+
+ .set noreorder
+ .set noat
+20: cache INDEX_WRITEBACK_INVALIDATE_SD,0(a0) // writeback/invalidate on index
+ bne a0,a1,20b // if ne, more to invalidate
+ addu a0,a0,t1 // compute address of next block
+ .set at
+ .set reorder
+
+30: j ra // return
+
+ .end HalSweepDcache
+
+ SBTTL("Sweep Data Cache Range")
+//++
+//
+// VOID
+// HalSweepDcacheRange (
+// IN PVOID BaseAddress,
+// IN ULONG Length
+// )
+//
+// Routine Description:
+//
+// This function sweeps (index/writeback/invalidate) the specified range
+// of virtual addresses from the primary data cache.
+//
+// Arguments:
+//
+// BaseAddress (a0) - Supplies the base address of the range that is swept
+// from the data cache.
+//
+// Length (a1) - Supplies the length of the range that is swept from the
+// data cache.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ LEAF_ENTRY(HalSweepDcacheRange)
+
+#if DBG
+
+ lw t0,KeDcacheFlushCount // get address of dcache flush count
+ lw t1,0(t0) // increment the count of flushes
+ addu t1,t1,1 //
+ sw t1,0(t0) // store result conditionally
+
+#endif
+
+ and a0,a0,COLOR_MASK // isolate color and offset bits
+ or a0,a0,KSEG0_BASE // convert to physical address
+ lw t0,KiPcr + PcFirstLevelDcacheFillSize(zero) // get block size
+ addu a1,a0,a1 // compute ending cache address
+ subu a1,a1,t0 // compute ending block address
+
+//
+// Sweep the primary data cache.
+//
+
+ .set noreorder
+ .set noat
+10: cache INDEX_WRITEBACK_INVALIDATE_D,0(a0) // writeback/invalidate on index
+ bne a0,a1,10b // if ne, more to invalidate
+ addu a0,a0,t0 // compute address of next block
+ .set at
+ .set reorder
+
+ j ra // return
+
+ .end HalSweepDcacheRange
+
+ SBTTL("Sweep Instruction Cache")
+//++
+//
+// VOID
+// HalSweepIcache (
+// VOID
+// )
+//
+// Routine Description:
+//
+// This function sweeps (index/invalidate) the entire instruction cache.
+//
+// Arguments:
+//
+// None.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ LEAF_ENTRY(HalSweepIcache)
+
+#if DBG
+
+ lw t0,KeIcacheFlushCount // get address of icache flush count
+ lw t1,0(t0) // increment the count of flushes
+ addu t1,t1,1 //
+ sw t1,0(t0) // store result
+
+#endif
+
+ lw t0,KiPcr + PcSecondLevelIcacheSize(zero) // get instruction cache size
+ lw t1,KiPcr + PcSecondLevelIcacheFillSize(zero) // get fill size
+ beq zero,t1,20f // if eq, no second level cache
+ li a0,KSEG0_BASE // set starting index value
+ addu a1,a0,t0 // compute ending cache address
+ subu a1,a1,t1 // compute ending block address
+
+//
+// Sweep the secondary instruction cache.
+//
+
+ .set noreorder
+ .set noat
+10: cache INDEX_INVALIDATE_SI,0(a0) // invalidate cache line
+ bne a0,a1,10b // if ne, more to invalidate
+ addu a0,a0,t1 // compute address of next block
+ .set at
+ .set reorder
+
+20: lw t0,KiPcr + PcFirstLevelIcacheSize(zero) // get instruction cache size
+ lw t1,KiPcr + PcFirstLevelIcacheFillSize(zero) // get fill size
+ li a0,KSEG0_BASE // set starting index value
+ addu a1,a0,t0 // compute ending cache address
+ subu a1,a1,t1 // compute ending block address
+
+//
+// Sweep the primary instruction cache.
+//
+
+ .set noreorder
+ .set noat
+30: cache INDEX_INVALIDATE_I,0(a0) // invalidate cache line
+ bne a0,a1,30b // if ne, more to invalidate
+ addu a0,a0,t1 // compute address of next block
+ .set at
+ .set reorder
+
+ j ra // return
+
+ .end HalSweepIcache
+
+ SBTTL("Sweep Instruction Cache Range")
+//++
+//
+// VOID
+// HalSweepIcacheRange (
+// IN PVOID BaseAddress,
+// IN ULONG Length
+// )
+//
+// Routine Description:
+//
+// This function sweeps (index/invalidate) the specified range of addresses
+// from the instruction cache.
+//
+// Arguments:
+//
+// BaseAddress (a0) - Supplies the base address of the range that is swept
+// from the instruction cache.
+//
+// Length (a1) - Supplies the length of the range that is swept from the
+// instruction cache.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ LEAF_ENTRY(HalSweepIcacheRange)
+
+#if DBG
+
+ lw t0,KeIcacheFlushCount // get address of icache flush count
+ lw t1,0(t0) // increment the count of flushes
+ addu t1,t1,1 //
+ sw t1,0(t0) // store result
+
+#endif
+
+ and a0,a0,COLOR_MASK // isolate color and offset bits
+ or a0,a0,KSEG0_BASE // convert to physical address
+ lw t0,KiPcr + PcFirstLevelIcacheFillSize(zero) // get fill size
+ addu a1,a0,a1 // compute ending cache address
+ subu a1,a1,t0 // compute ending block address
+
+//
+// Sweep the primary instruction cache.
+//
+
+ .set noreorder
+ .set noat
+10: cache INDEX_INVALIDATE_I,0(a0) // invalidate cache line
+ bne a0,a1,10b // if ne, more to invalidate
+ addu a0,a0,t0 // compute address of next block
+ .set at
+ .set reorder
+
+ j ra // return
+
+ .end HalSweepIcacheRange
+
+ SBTTL("Zero Page")
+//++
+//
+// VOID
+// HalZeroPage (
+// IN PVOID NewColor,
+// IN PVOID OldColor,
+// IN ULONG PageFrame
+// )
+//
+// Routine Description:
+//
+// This function zeros a page of memory.
+//
+// The algorithm used to zero a page is as follows:
+//
+// 1. Purge (hit/invalidate) the page from the instruction cache
+// using the old color iff the old color is not the same as
+// the new color.
+//
+// 2. Purge (hit/invalidate) the page from the data cache using
+// the old color iff the old color is not the same as the new
+// color.
+//
+// 3. Create (create/dirty/exclusive) the page in the data cache
+// using the new color.
+//
+// 4. Write zeros to the page using the new color.
+//
+// Arguments:
+//
+// NewColor (a0) - Supplies the page aligned virtual address of the
+// new color of the page that is zeroed.
+//
+// OldColor (a1) - Supplies the page aligned virtual address of the
+// old color of the page that is zeroed.
+//
+// PageFrame (a2) - Supplies the page frame number of the page that
+// is zeroed.
+//
+// Return Value:
+//
+// None.
+//
+//--
+
+ .struct 0
+ .space 3 * 4 // fill
+ZpRa: .space 4 // saved return address
+ZpFrameLength: // length of stack frame
+ZpA0: .space 4 // (a0)
+ZpA1: .space 4 // (a1)
+ZpA2: .space 4 // (a2)
+ZpA3: .space 4 // (a3)
+
+ NESTED_ENTRY(HalZeroPage, ZpFrameLength, zero)
+
+ subu sp,sp,ZpFrameLength // allocate stack frame
+ sw ra,ZpRa(sp) // save return address
+
+ PROLOGUE_END
+
+ and a0,a0,COLOR_BITS // isolate new color bits
+ and a1,a1,COLOR_BITS // isolate old color bits
+ sw a0,ZpA0(sp) // save new color bits
+ sw a1,ZpA1(sp) // save old color bits
+ sw a2,ZpA2(sp) // save page frame
+
+//
+// Purge the instruction cache using the old page color iff the old page
+// color is not equal to the new page color.
+//
+
+ beq a0,a1,10f // if eq, colors match
+ move a0,a1 // set old color value
+ move a1,a2 // set page frame number
+ li a2,PAGE_SIZE // set length of purge
+ jal HalPurgeIcachePage // purge instruction cache page
+
+//
+// Purge the data cache using the old page color iff the old page color is
+// not equal to the new page color.
+//
+
+ lw a0,ZpA1(sp) // get old color value
+ lw a1,ZpA2(sp) // get page frame number
+ li a2,PAGE_SIZE // set length of purge
+ jal HalPurgeDcachePage // purge data cache page
+
+//
+// Create dirty exclusive cache blocks and zero the data.
+//
+
+10: lw a3,ZpA0(sp) // get new color bits
+ lw a1,ZpA2(sp) // get page frame number
+
+ .set noreorder
+ .set noat
+ lw v0,KiPcr + PcAlignedCachePolicy(zero) // get cache polciy
+ li t0,FLUSH_BASE // get base flush address
+ or t0,t0,a3 // compute new color virtual address
+ sll t1,a1,ENTRYLO_PFN // shift page frame into position
+ or t1,t1,PROTECTION_BITS // merge protection bits
+ or t1,t1,v0 // merge cache policy
+ and a3,a3,0x1000 // isolate TB entry index
+ beql zero,a3,20f // if eq, first entry
+ move t2,zero // set second page table entry
+ move t2,t1 // set second page table entry
+ move t1,zero // set first page table entry
+20: mfc0 t3,wired // get TB entry index
+ lw t4,KiPcr + PcFirstLevelDcacheFillSize(zero) // get 1st fill size
+ lw v0,KiPcr + PcSecondLevelDcacheFillSize(zero) // get 2nd fill size
+ .set at
+ .set reorder
+
+ DISABLE_INTERRUPTS(t5) // disable interrupts
+
+ .set noreorder
+ .set noat
+ mfc0 t6,entryhi // get current PID and VPN2
+ srl t7,t0,ENTRYHI_VPN2 // isolate VPN2 of virtual address
+ sll t7,t7,ENTRYHI_VPN2 //
+ and t6,t6,0xff << ENTRYHI_PID // isolate current PID
+ or t7,t7,t6 // merge PID with VPN2 of virtual address
+ mtc0 t7,entryhi // set VPN2 and PID for probe
+ mtc0 t1,entrylo0 // set first PTE value
+ mtc0 t2,entrylo1 // set second PTE value
+ mtc0 t3,index // set TB index value
+ nop // fill
+ tlbwi // write TB entry - 3 cycle hazzard
+ addu t9,t0,PAGE_SIZE // compute ending address of block
+ dmtc1 zero,f0 // set write pattern
+ bne zero,v0,50f // if ne, second level cache present
+ and t8,t4,0x10 // test if 16-byte cache block
+
+//
+// Zero page in primary data cache only.
+//
+
+30: cache CREATE_DIRTY_EXCLUSIVE_D,0(t0) // create cache block
+ addu t0,t0,t4 // compute next block address
+ bne zero,t8,40f // if ne, 16-byte cache line
+ sdc1 f0,-16(t0) //
+ sdc1 f0,-24(t0) // zero 16 bytes
+ sdc1 f0,-32(t0) //
+40: bne t0,t9,30b // if ne, more blocks to zero
+ sdc1 f0,-8(t0) // zero 16 bytes
+ .set at
+ .set reorder
+
+ ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ lw ra,ZpRa(sp) // get return address
+ addu sp,sp,ZpFrameLength // deallocate stack frame
+ j ra // return
+
+//
+// Zero page in primary and secondary data caches.
+//
+
+ .set noreorder
+ .set noat
+50: cache CREATE_DIRTY_EXCLUSIVE_SD,0(t0) // create secondary cache block
+ addu v1,v0,t0 // compute ending primary block address
+60: addu t0,t0,t4 // compute next block address
+ bne zero,t8,70f // if ne, 16-byte primary cache line
+ sdc1 f0,-16(t0) //
+ sdc1 f0,-24(t0) // zero 16 bytes
+ sdc1 f0,-32(t0) //
+70: bne t0,v1,60b // if ne, more primary blocks to zero
+ sdc1 f0,-8(t0) // zero 16 bytes
+ bne t0,t9,50b // if ne, more secondary blocks to zero
+ nop // fill
+ .set at
+ .set reorder
+
+ ENABLE_INTERRUPTS(t5) // enable interrupts
+
+ lw ra,ZpRa(sp) // get return address
+ addu sp,sp,ZpFrameLength // deallocate stack frame
+ j ra // return
+
+ .end HalZeroPage
+
+#endif