- Remove stale comments
- Replace a1 with k1 to while restoring context. a1 was there by mistake, interrupts are disabled at this point and it's safe to use k0, k1. This code never was reached beacasue current Status register handling prevented interrupta from user mode.
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070f07e3de
@ -689,36 +689,27 @@ NNON_LEAF(MipsUserIntr, STAND_FRAME_SIZE, ra)
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/*
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* Call the interrupt handler.
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*/
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break
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la k0, _C_LABEL(cpu_intr)
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jalr k0
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sw a3, STAND_RA_OFFSET(sp) # for debugging
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/*
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* Since interrupts are enabled at this point, we use a1 instead of
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* k0 or k1 to store the PCB pointer. This is because k0 and k1
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* are not preserved across interrupts. ** RRS - And how did the
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* get enabled? cpu_intr clears the cause register but it does
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* not touch the sr as far as I can see thus intr are still
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* disabled.
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* DO_AST enabled interrupts
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*/
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DO_AST
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/*
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* Restore user registers and return. NOTE: interrupts are enabled.
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* Restore user registers and return.
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*/
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/*
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* Since interrupts are enabled at this point, we use a1 instead of
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* k0 or k1 to store the PCB pointer. This is because k0 and k1
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* are not preserved across interrupts.
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*/
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mtc0 zero, COP_0_STATUS_REG
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mtc0 zero, COP_0_STATUS_REG # re-disable interrupts
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ITLBNOPFIX
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li v0, SR_EXL
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mtc0 v0, COP_0_STATUS_REG # set exeption level bit.
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ITLBNOPFIX
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GET_CPU_PCPU(k1)
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lw a1, PC_CURPCB(k1)
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lw k1, PC_CURPCB(k1)
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RESTORE_U_PCB_REG(s0, S0, k1)
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RESTORE_U_PCB_REG(s1, S1, k1)
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RESTORE_U_PCB_REG(s2, S2, k1)
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