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interrupt_handler.s
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# Tim Henderson & Steve Johnson
# interrupt handler
# This is where the magic happens
# # .globl __save_gp
# # .globl __save_sp
# # .globl __save_fp
# # .globl __save_ra
# # .globl __save_t0
# # .globl __save_t1
# # .globl __save_t2
# # .globl __save_t3
# # .globl __save_s0
# # .globl __save_s1
# # .globl __save_s2
# # .globl __save_s3
.data
__save_gp: .word 0
__save_sp: .word 0
__save_fp: .word 0
__save_ra: .word 0
__save_t0: .word 0
__save_t1: .word 0
__save_t2: .word 0
__save_t3: .word 0
__save_t4: .word 0
__save_t5: .word 0
__save_t6: .word 0
__save_t7: .word 0
__save_t8: .word 0
__save_t9: .word 0
__save_s0: .word 0
__save_s1: .word 0
__save_s2: .word 0
__save_s3: .word 0
__save_s4: .word 0
__save_s5: .word 0
__save_s6: .word 0
__save_s7: .word 0
__save_HCB_ADDR: .word 0
__k_HCB_ADDR: .word 0
.text
save_state:
{
sw $gp __save_gp # save the pointer registers
sw $sp __save_sp
sw $fp __save_fp
sw $ra __save_ra
sw $t0 __save_t0 # save $t0 - $t3
sw $t1 __save_t1
sw $t2 __save_t2
sw $t3 __save_t3
sw $t4 __save_t4
sw $t5 __save_t5
sw $t6 __save_t6
sw $t7 __save_t7
sw $t8 __save_t8
sw $t9 __save_t9
sw $s0 __save_s0 # save $s0 - $s3
sw $s1 __save_s1
sw $s2 __save_s2
sw $s3 __save_s3
sw $s4 __save_s4 # save $s0 - $s3
sw $s5 __save_s5
sw $s6 __save_s6
sw $s7 __save_s7
j save_state_return
}
.text
restore_state:
{
lw $t0 __save_t0 # load $t0 - $t3
lw $t1 __save_t1
lw $t2 __save_t2
lw $t3 __save_t3
lw $t4 __save_t4
lw $t5 __save_t5
lw $t6 __save_t6
lw $t7 __save_t7
lw $t8 __save_t8
lw $t9 __save_t9
lw $s0 __save_s0 # load $s0 - $s3
lw $s1 __save_s1
lw $s2 __save_s2
lw $s3 __save_s3
lw $s4 __save_s4
lw $s5 __save_s5
lw $s6 __save_s6
lw $s7 __save_s7
lw $gp __save_gp # load the pointer registers
lw $sp __save_sp
lw $fp __save_fp
lw $ra __save_ra
j restore_state_return
}
.data
__int_msg: .asciiz "interrupt handler entered\n"
.text
interrupt_handler:
# la $a0, __int_msg # load the addr of exception_msg into $a0.
# li $v0, 4 # 4 is the print_string syscall.
# syscall # do the syscall.
j save_state
save_state_return:
{
la $a0 current_pcb
lw $a0 0($a0)
li $a1 0
call save_proc
######### SAVE THE STACK #########
{
@hcb_addr = $s1
@pcb_id = $s2
@sp = $s3
@error = $s4
@stack_id = $s5
@stackheap = $s6
@curpcb_addr = $t0
khcb_getaddr @hcb_addr
la @curpcb_addr current_pcb
lw @pcb_id 0(@curpcb_addr)
geti 7 @pcb_id @hcb_addr @sp @error
# bne @error $zero put_error
addu $a0 @sp $zero
call save_stack
addu @stack_id $v0 $zero
#println_hex sstr @stack_id
puti 4 @pcb_id @hcb_addr @stack_id @error
# bne @error $zero put_error
###uncomment this to zero the stack after saving it###
#geti 3 $0 @hcb_addr @stackheap @error
#print_hcb @stackheap
#printblock @stack_id @stackheap
#addu $a0 @sp $zero
#call zero_stack
}
######### SAVE THE STACK #########
la $a0 KMSG
lw $a0 0($a0)
beqz $a0 km_clock_interrupt
li $a1 1
beq $a0 $a1 km_wait
li $a1 2
beq $a0 $a1 km_exit
b reset_kmsg #default: do nothing
km_wait:
{
@khcb_addr = $s0
@h = $s1
@err = $s2
@pid = $s3
@pcb = $s4
@mem_id = $s5
khcb_getaddr @khcb_addr
geti 1 $zero @khcb_addr @h @err
bnez @err ch_err
la $a0 current_pid
lw @pid 0($a0)
addu $a0 @h $zero
addu $a1 @pid $zero #this is the old pid
call ll_find_pid
addu @mem_id $v0 $zero
addu $a0 @h $zero
addu $a1 @mem_id $zero #where mem_id is a list node
call ll_next
addu @mem_id $v0 $zero
geti 1 @mem_id @khcb_addr @pid @err
bnez @err ch_err
geti 2 @mem_id @khcb_addr @pcb @err
bnez @err ch_err
la $a0 current_pid
sw @pid 0($a0)
la $a0 current_pcb
sw @pcb 0($a0)
b noerr
ch_err:
println errmsg
li $v0 10
syscall
.data
errmsg: .asciiz "error in cmgr_wait"
.text
noerr:
}
b reset_kmsg
km_exit:
{
@khcb_addr = $s0
@h = $s1
@err = $s2
@pid = $s3
@pcb = $s4
@mem_id = $s5
khcb_getaddr @khcb_addr
geti 1 $zero @khcb_addr @h @err
bnez @err ex_err
la $a0 current_pid
lw @pid 0($a0)
addu $a0 @h $zero
addu $a1 @pid $zero #this is the old pid
call ll_find_pid
addu @mem_id $v0 $zero
#println_hex memid_msg @mem_id
addu $a0 @h $zero
addu $a1 @mem_id $zero #where mem_id is the list node to remove
call ll_remove
addu @h $v0 $zero
khcb_getaddr @khcb_addr
puti 1 $zero @khcb_addr @h @err
addu $a0 @h $zero
addu $a1 @h $zero
call ll_next
addu @mem_id $v0 $zero
geti 1 @mem_id @khcb_addr @pid @err
bnez @err ex_err
geti 2 @mem_id @khcb_addr @pcb @err
bnez @err ex_err
la $a0 current_pid
sw @pid 0($a0)
la $a0 current_pcb
sw @pcb 0($a0)
b noerr
ex_err:
println errmsg
li $v0 10
syscall
.data
errmsg: .asciiz "error in cmgr_exit"
.text
noerr:
}
b reset_kmsg
km_clock_interrupt:
#do nothing
b reset_kmsg
reset_kmsg:
la $a0 KMSG
sw $zero 0($a0)
# la $a0 current_pcb
# lw $a0 0($a0)
# call restore_proc
# {
# @hcb_addr = $s1
# @curpcb_addr = $s2
# @pcb_id = $s3
# khcb_getaddr @hcb_addr
# la @curpcb_addr current_pcb
# lw @pcb_id 0(@curpcb_addr)
#
# printblock @pcb_id @hcb_addr
# }
la $a0 current_pcb
lw $a0 0($a0)
call restore_proc
######### RESTORE THE STACK ##########
{
@hcb_addr = $s1
@pcb_id = $s2
@error = $s3
@curpcb_addr = $s4
@stack_id = $s5
@sp = $s6
khcb_getaddr @hcb_addr
la @curpcb_addr current_pcb
lw @pcb_id 0(@curpcb_addr)
geti 7 @pcb_id @hcb_addr @sp @error
geti 4 @pcb_id @hcb_addr @stack_id @error
#println_hex rstr @stack_id
addu $a0 @stack_id $0
addu $a1 @sp $0
call restore_stack
}
######### RESTORE THE STACK ##########
}
j restore_state
restore_state_return:
la $a0 interrupt_return
jr $a0
# j interrupt_return
.data
rstr: .asciiz "Loading stack_id "
sstr: .asciiz "Saving stack_id "
memid_msg: .asciiz "mem_id: "
.text