1/* SPDX-License-Identifier: GPL-2.0+ */ 2/* 3 * (C) Copyright 2004, Psyent Corporation <www.psyent.com> 4 * Scott McNutt <smcnutt@psyent.com> 5 */ 6 7#include <config.h> 8#include <asm/opcodes.h> 9 10 11 .text 12 .align 4 13 14 .global _exception 15 16 .set noat 17 .set nobreak 18 19_exception: 20 /* SAVE ALL REGS -- this allows trap and unimplemented 21 * instruction handlers to be coded conveniently in C 22 */ 23 addi sp, sp, -(33*4) 24 stw r0, 0(sp) 25 stw r1, 4(sp) 26 stw r2, 8(sp) 27 stw r3, 12(sp) 28 stw r4, 16(sp) 29 stw r5, 20(sp) 30 stw r6, 24(sp) 31 stw r7, 28(sp) 32 stw r8, 32(sp) 33 stw r9, 36(sp) 34 stw r10, 40(sp) 35 stw r11, 44(sp) 36 stw r12, 48(sp) 37 stw r13, 52(sp) 38 stw r14, 56(sp) 39 stw r15, 60(sp) 40 stw r16, 64(sp) 41 stw r17, 68(sp) 42 stw r19, 72(sp) 43 stw r19, 76(sp) 44 stw r20, 80(sp) 45 stw r21, 84(sp) 46 stw r22, 88(sp) 47 stw r23, 92(sp) 48 stw r24, 96(sp) 49 stw r25, 100(sp) 50 stw r26, 104(sp) 51 stw r27, 108(sp) 52 stw r28, 112(sp) 53 stw r29, 116(sp) 54 stw r30, 120(sp) 55 stw r31, 124(sp) 56 rdctl et, estatus 57 stw et, 128(sp) 58 59 /* If interrupts are disabled -- software interrupt */ 60 rdctl et, estatus 61 andi et, et, 1 62 beq et, r0, 0f 63 64 /* If no interrupts are pending -- software interrupt */ 65 rdctl et, ipending 66 beq et, r0, 0f 67 68 /* HARDWARE INTERRUPT: Call interrupt handler */ 69 movhi r3, %hi(external_interrupt) 70 ori r3, r3, %lo(external_interrupt) 71 mov r4, sp /* ptr to regs */ 72 callr r3 73 74 /* Return address fixup: execution resumes by re-issue of 75 * interrupted instruction at ea-4 (ea == r29). Here we do 76 * simple fixup to allow common exception return. 77 */ 78 ldw r3, 116(sp) 79 addi r3, r3, -4 80 stw r3, 116(sp) 81 br _exception_return 82 830: 84 /* TRAP EXCEPTION */ 85 movhi r3, %hi(OPC_TRAP) 86 ori r3, r3, %lo(OPC_TRAP) 87 addi r1, ea, -4 88 ldw r1, 0(r1) 89 bne r1, r3, 1f 90 movhi r3, %hi(trap_handler) 91 ori r3, r3, %lo(trap_handler) 92 mov r4, sp /* ptr to regs */ 93 callr r3 94 br _exception_return 95 961: 97 /* UNIMPLEMENTED INSTRUCTION EXCEPTION */ 98 movhi r3, %hi(soft_emulation) 99 ori r3, r3, %lo(soft_emulation) 100 mov r4, sp /* ptr to regs */ 101 callr r3 102 103 /* Restore regsisters and return from exception*/ 104_exception_return: 105 ldw r1, 4(sp) 106 ldw r2, 8(sp) 107 ldw r3, 12(sp) 108 ldw r4, 16(sp) 109 ldw r5, 20(sp) 110 ldw r6, 24(sp) 111 ldw r7, 28(sp) 112 ldw r8, 32(sp) 113 ldw r9, 36(sp) 114 ldw r10, 40(sp) 115 ldw r11, 44(sp) 116 ldw r12, 48(sp) 117 ldw r13, 52(sp) 118 ldw r14, 56(sp) 119 ldw r15, 60(sp) 120 ldw r16, 64(sp) 121 ldw r17, 68(sp) 122 ldw r19, 72(sp) 123 ldw r19, 76(sp) 124 ldw r20, 80(sp) 125 ldw r21, 84(sp) 126 ldw r22, 88(sp) 127 ldw r23, 92(sp) 128 ldw r24, 96(sp) 129 ldw r25, 100(sp) 130 ldw r26, 104(sp) 131 ldw r27, 108(sp) 132 ldw r28, 112(sp) 133 ldw r29, 116(sp) 134 ldw r30, 120(sp) 135 ldw r31, 124(sp) 136 addi sp, sp, (33*4) 137 eret 138/*-------------------------------------------------------------*/ 139