57 lines
1 KiB
ArmAsm
57 lines
1 KiB
ArmAsm
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.sect .text
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.define .trap_ecase
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.trap_ecase:
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li r3, 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 r3 = trap number.
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.define .trp
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.trp:
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cmplwi r3, 15 ! traps > 15 can't be ignored
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bgt 1f
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lis r4, ha16[.ignmask]
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lwz r4, lo16[.ignmask](r4) ! load ignore mask
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srw r4, r4, r3
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andi. r4, r4, 1
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bnelr ! return if ignoring trap
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1: lis r4, ha16[.trppc]
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lwz r5, lo16[.trppc](r4) ! r5 = user trap routine
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mr. r5, r5
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beq 2f ! if no user trap routine, bail out
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mtspr ctr, r5
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mfspr r6, lr
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li r0, 0
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stwu r3, -8(sp) ! push trap number
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stw r0, lo16[.trppc](r4) ! reset trap routine
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stw r6, 4(sp) ! save old lr
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bctrl ! call trap routine
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lwz r0, 4(sp)
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mtspr lr, r0
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addi sp, sp, 8 ! retract over stack usage
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blr
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2: ! No trap handler. Write error message, exit.
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li r3, 2
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stwu r3, -12(sp)
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lis r4, ha16[message]
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addi r4, r4, lo16[message]
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li r5, 6
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stw r4, 4(sp)
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stw r5, 8(sp)
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bl _write ! write(2, message, 6)
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li r3, 1
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stw r3, 0(sp)
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bl __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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