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/* $Id: r2300_switch.S,v 1.3 1996/06/29 07:06:42 dm Exp $
* r2300_switch.S: R3000/R2000 specific task switching code.
*
* Copyright (C) 1994, 1995, 1996 by Ralf Baechle and Andreas Busse
*
* Multi-cpu abstraction and macros for easier reading:
* Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
*/
#include <asm/asm.h>
#include <asm/bootinfo.h>
#include <asm/cachectl.h>
#include <asm/current.h>
#include <asm/fpregdef.h>
#include <asm/mipsconfig.h>
#include <asm/mipsregs.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/regdef.h>
#include <asm/stackframe.h>
#include <asm/asmmacro.h>
/* XXX The following is fucking losing... find a better way dave. */
MODE_ALIAS = 0x00e0 # uncachable, dirty, valid
.text
.set mips3
/*
* Code necessary to switch tasks on an Linux/MIPS machine.
* FIXME: We don't need to disable interrupts anymore.
*/
.align 5
LEAF(r2300_resume)
GET_CURRENT(t0)
mfc0 t1,CP0_STATUS # Save status register
addu t0,a1 # Add tss offset
sw t1,THREAD_STATUS(t0)
ori t2,t1,0x1f # Disable interrupts
xori t2,0x1e
mtc0 t2,CP0_STATUS
CPU_SAVE_NONSCRATCH(t0)
sll t2,t1,2 # Save floating point state
bgez t2,2f
sw ra,THREAD_REG31(t0)
sll t2,t1,5
bgez t2,1f
swc1 $f0, (THREAD_FPU + 0x00)(t0)
FPU_SAVE_16ODD(t0)
1:
FPU_SAVE_16EVEN(t0, t1)
2:
addu a0,a1 # Add tss offset
lw t0,THREAD_PGDIR(a0) # Switch the root pointer
li t1,TLB_ROOT # get PFN
mtc0 t1,CP0_ENTRYHI
mtc0 zero,CP0_INDEX
srl t0,12 # PFN is 12 bits west
ori t0,MODE_ALIAS # want uncachable, dirty, valid
mtc0 t0,CP0_ENTRYLO0
lw a2,THREAD_STATUS(a0)
tlbwi
/* Flush TLB. */
mfc0 t3,CP0_STATUS # disable interrupts...
ori t4,t3,1
xori t4,1
mtc0 t4,CP0_STATUS
lw t0,mips_tlb_entries
mtc0 zero,CP0_ENTRYLO0
1:
subu t0,1
mtc0 t0,CP0_INDEX
lui t1,0x0008
or t1,t0,t1
sll t1,12
mtc0 t1,CP0_ENTRYHI
bne t2,t0,1b
tlbwi
ori t1,a2,1 # Restore FPU, pipeline magic
xori t1,1
mtc0 t1,CP0_STATUS
sll t0,a2,2
bgez t0,2f
sll t0,a2,5
bgez t0,1f
lwc1 $f0, (THREAD_FPU + 0x00)(a0)
FPU_RESTORE_16ODD(a0)
1:
FPU_RESTORE_16EVEN(a0, t0)
2:
CPU_RESTORE_NONSCRATCH(a0)
lw t0,THREAD_KSP(a0) # Restore status register
sw t0,kernelsp
jr ra
mtc0 a2,CP0_STATUS
END(r2300_resume)
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