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; ###----------------------------------------------------------------###
; # file : exc003.s #
; # date : Mar 26 1996 #
; # descr. : functional test for mips #
; ###----------------------------------------------------------------###
; ###--------------------------------------------------------###
; # exceptions : #
; # - overflow (when adding positive numbers) #
; ###--------------------------------------------------------###
val1 .equ 0x3C ; arithmetic overflow
system_stack .equ 0xC0000000 ; system stack address
user_prog .equ 0x00400000
val .equ 0x30
.org 0x80000080
.start it_handler
; ###--------------------------------------------------------###
; # interrupt and exception handler #
; ###--------------------------------------------------------###
it_handler:
sw r29, 0 (r30)
sw r28, 4 (r30)
addi r28, r0 ,val1
mfc0 r29,cause
nop
and r29, r29, r28 ; data address violation ?
addiu r27,r0,val
bne r29,r27, other_causes
nop
lw r29, 0 (r30)
lw r28, 4 (r30)
; ###--------------------------------------------------------###
; # restore return address before returning (from EXCEPTION) #
; # to the user program (address must be saved by the user #
; # prior to the EXCEPTION in epc) #
; ###--------------------------------------------------------###
restore_return_adr:
mfc0 r1,epc
nop
addiu r1,r1,4
j return
nop
other_causes: j other_causes
nop
; ###--------------------------------------------------------###
; # return to the interrupted program #
; ###--------------------------------------------------------###
.org 0x800000d0
return:
rfe
jr r1
.end
|
