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|
.include "t-macros.i"
start
mtc0 $0,$12
mtc0 $0,$11
mtc0 $0,$13
# install our jump table
la $24, jump_table
li $25, 0x80000180
li $26, 0xbfc00380
lw $27, 0($24)
sw $27, 0($25)
sw $27, 0($26)
lw $27, 4($24)
sw $27, 4($25)
sw $27, 4($26)
lw $27, 8($24)
sw $27, 8($25)
sw $27, 8($26)
la $25, LocalHandler
la $27, address_trap
la $31, address_return
li $2, 1
li $3, 1
address_trap:
tge $2, $3
b fail
address_return:
exit0
fail:
exit47
jump_table:
.align 7
la $24, LocalHandler
jr $24
.align 7
LocalHandler:
mfc0 $25,$12
andi $7,$25,0x002 # check that exl bit was set
beq $7,$0,fail
mfc0 $25,$14
bne $27,$25,fail # compare with the exception program counter
mfc0 $25,$13
andi $25,$25,0x000000ff # extract excpt code, not checking int*[5:0]
li $8,(( 13 )<<2) # expected value of cause register
bne $25,$8,fail
mtc0 $31,$14 # return address from handler
nop
nop
nop
nop
eret
nop
|
