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Diffstat (limited to 'cpu/nios2/exceptions.S')
-rw-r--r-- | cpu/nios2/exceptions.S | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/cpu/nios2/exceptions.S b/cpu/nios2/exceptions.S new file mode 100644 index 0000000..d3b95cf --- /dev/null +++ b/cpu/nios2/exceptions.S @@ -0,0 +1,152 @@ +/* + * (C) Copyright 2004, Psyent Corporation <www.psyent.com> + * Scott McNutt <smcnutt@psyent.com> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <config.h> +#include <asm/opcodes.h> + + + .text + .align 4 + + .global _exception + +_exception: + /* SAVE ALL REGS -- this allows trap and unimplemented + * instruction handlers to be coded conveniently in C + */ + addi sp, sp, -(33*4) + stw r0, 0(sp) + stw r1, 4(sp) + stw r2, 8(sp) + stw r3, 12(sp) + stw r4, 16(sp) + stw r5, 20(sp) + stw r6, 24(sp) + stw r7, 28(sp) + stw r8, 32(sp) + stw r9, 36(sp) + stw r10, 40(sp) + stw r11, 44(sp) + stw r12, 48(sp) + stw r13, 52(sp) + stw r14, 56(sp) + stw r15, 60(sp) + stw r16, 64(sp) + stw r17, 68(sp) + stw r19, 72(sp) + stw r19, 76(sp) + stw r20, 80(sp) + stw r21, 84(sp) + stw r22, 88(sp) + stw r23, 92(sp) + stw r24, 96(sp) + stw r25, 100(sp) + stw r26, 104(sp) + stw r27, 108(sp) + stw r28, 112(sp) + stw r29, 116(sp) + stw r30, 120(sp) + stw r31, 124(sp) + rdctl et, estatus + stw et, 128(sp) + + /* If interrupts are disabled -- software interrupt */ + rdctl et, estatus + andi et, et, 1 + beq et, r0, 0f + + /* If no interrupts are pending -- software interrupt */ + rdctl et, ipending + beq et, r0, 0f + + /* HARDWARE INTERRUPT: Call interrupt handler */ + movhi r3, %hi(external_interrupt) + ori r3, r3, %lo(external_interrupt) + mov r4, sp /* ptr to regs */ + callr r3 + + /* Return address fixup: execution resumes by re-issue of + * interrupted instruction at ea-4 (ea == r29). Here we do + * simple fixup to allow common exception return. + */ + ldw r3, 116(sp) + addi r3, r3, -4 + stw r3, 116(sp) + br _exception_return + +0: + /* TRAP EXCEPTION */ + movhi r3, %hi(OPC_TRAP) + ori r3, r3, %lo(OPC_TRAP) + addi r1, ea, -4 + ldw r1, 0(r1) + bne r1, r3, 1f + movhi r3, %hi(trap_handler) + ori r3, r3, %lo(trap_handler) + mov r4, sp /* ptr to regs */ + callr r3 + br _exception_return + +1: + /* UNIMPLEMENTED INSTRUCTION EXCEPTION */ + movhi r3, %hi(soft_emulation) + ori r3, r3, %lo(soft_emulation) + mov r4, sp /* ptr to regs */ + callr r3 + + /* Restore regsisters and return from exception*/ +_exception_return: + ldw r1, 4(sp) + ldw r2, 8(sp) + ldw r3, 12(sp) + ldw r4, 16(sp) + ldw r5, 20(sp) + ldw r6, 24(sp) + ldw r7, 28(sp) + ldw r8, 32(sp) + ldw r9, 36(sp) + ldw r10, 40(sp) + ldw r11, 44(sp) + ldw r12, 48(sp) + ldw r13, 52(sp) + ldw r14, 56(sp) + ldw r15, 60(sp) + ldw r16, 64(sp) + ldw r17, 68(sp) + ldw r19, 72(sp) + ldw r19, 76(sp) + ldw r20, 80(sp) + ldw r21, 84(sp) + ldw r22, 88(sp) + ldw r23, 92(sp) + ldw r24, 96(sp) + ldw r25, 100(sp) + ldw r26, 104(sp) + ldw r27, 108(sp) + ldw r28, 112(sp) + ldw r29, 116(sp) + ldw r30, 120(sp) + ldw r31, 124(sp) + addi sp, sp, (33*4) + eret +/*-------------------------------------------------------------*/ |