65 lines
1.2 KiB
ArmAsm
65 lines
1.2 KiB
ArmAsm
#
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.sect .text; .sect .rom; .sect .data; .sect .bss
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.sect .text
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.define .trap_ecase
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.trap_ecase:
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li r4, 20 ! ECASE = 20 in h/em_abs.h
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! FALLTHROUGH to .trp
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! Raises an EM trap.
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! Expects r4 = trap number.
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.define .trp
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.trp:
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andi at, r4, 0xfff0
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bne at, zero, 1f ! traps > 15 can't be ignored
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nop
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lui at, ha16[.ignmask]
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lw r5, lo16[.ignmask] (at) ! load ignore mask
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srlv r5, r5, r4
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andi r5, r5, 1
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bne r5, zero, return ! return if ignoring trap
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nop
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1:
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lui at, ha16[.trppc]
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lw r5, lo16[.trppc] (at) ! r5 = user trap routine
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sw zero, lo16[.trppc] (at) ! reset the trap routine for next time
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beq r5, zero, abend ! abort if no user trap routine
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nop
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addiu sp, sp, -8
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sw r4, 0(sp) ! push trap number
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sw ra, 4(sp) ! and link register
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jalr r5 ! call trap routine
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nop
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lw ra, 4(sp) ! ...and return
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addiu sp, sp, 8
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return:
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jr ra
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nop
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! No trap handler; write error message and exit.
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abend:
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addiu sp, sp, -12
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li at, 2
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sw at, 0(sp)
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lui at, hi16[message]
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ori at, at, lo16[message]
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sw at, 4(sp)
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li at, 6
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sw at, 8(sp)
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jal _write ! write(2, message, 6)
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nop
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li at, 1
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sw at, 0(sp)
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j __exit ! _exit(1)
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.sect .rom
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message:
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.ascii "TRAP!\n"
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