76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
/* Copyright (C) 2013-2019 Free Software Foundation, Inc.
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Contributed by Altera and Mentor Graphics, Inc.
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This file is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3, or (at your option) any
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later version.
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This file is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* Set up trampolines.
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R12 is the static chain register.
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R2 is AT, the assembler temporary.
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The trampoline code looks like:
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movhi r12,%hi(chain)
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ori r12,%lo(chain)
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movhi r2,%hi(fn)
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ori r2,%lo(fn)
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jmp r2
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*/
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#define SC_REGNO 12
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/* Instruction encodings depend on the ISA level. */
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#if __nios2_arch__ == 2
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#define MOVHI(reg,imm16) \
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(((reg) << 11) | ((imm16) << 16) | 0x34)
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#define ORI(reg,imm16) \
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(((reg) << 11) | ((reg) << 6) | ((imm16) << 16) | 0x14)
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#define JMP(reg) \
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(((reg) << 6) | (0x0d << 26) | 0x20)
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#elif __nios2_arch__ == 1
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#define MOVHI(reg,imm16) \
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(((reg) << 22) | ((imm16) << 6) | 0x34)
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#define ORI(reg,imm16) \
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(((reg) << 27) | ((reg) << 22) | ((imm16) << 6) | 0x14)
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#define JMP(reg) \
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(((reg) << 27) | (0x0d << 11) | 0x3a)
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#else
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#error "Unknown Nios II architecture level"
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#endif
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void
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__trampoline_setup (unsigned int *addr, void *fnptr, void *chainptr)
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{
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unsigned int fn = (unsigned int) fnptr;
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unsigned int chain = (unsigned int) chainptr;
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int i;
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addr[0] = MOVHI (SC_REGNO, ((chain >> 16) & 0xffff));
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addr[1] = ORI (SC_REGNO, (chain & 0xffff));
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addr[2] = MOVHI (2, ((fn >> 16) & 0xffff));
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addr[3] = ORI (2, (fn & 0xffff));
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addr[4] = JMP (2);
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/* Flush the caches.
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See Example 9-4 in the Nios II Software Developer's Handbook. */
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for (i = 0; i < 5; i++)
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asm volatile ("flushd 0(%0); flushi %0" :: "r"(addr + i) : "memory");
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asm volatile ("flushp" ::: "memory");
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}
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