tramp.c revision 1.1.1.6
1/* Copyright (C) 2013-2018 Free Software Foundation, Inc. 2 Contributed by Altera and Mentor Graphics, Inc. 3 4This file is free software; you can redistribute it and/or modify it 5under the terms of the GNU General Public License as published by the 6Free Software Foundation; either version 3, or (at your option) any 7later version. 8 9This file is distributed in the hope that it will be useful, but 10WITHOUT ANY WARRANTY; without even the implied warranty of 11MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12General Public License for more details. 13 14Under Section 7 of GPL version 3, you are granted additional 15permissions described in the GCC Runtime Library Exception, version 163.1, as published by the Free Software Foundation. 17 18You should have received a copy of the GNU General Public License and 19a copy of the GCC Runtime Library Exception along with this program; 20see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 21<http://www.gnu.org/licenses/>. */ 22 23/* Set up trampolines. 24 R12 is the static chain register. 25 R2 is AT, the assembler temporary. 26 The trampoline code looks like: 27 movhi r12,%hi(chain) 28 ori r12,%lo(chain) 29 movhi r2,%hi(fn) 30 ori r2,%lo(fn) 31 jmp r2 32*/ 33 34#define SC_REGNO 12 35 36/* Instruction encodings depend on the ISA level. */ 37#if __nios2_arch__ == 2 38#define MOVHI(reg,imm16) \ 39 (((reg) << 11) | ((imm16) << 16) | 0x34) 40#define ORI(reg,imm16) \ 41 (((reg) << 11) | ((reg) << 6) | ((imm16) << 16) | 0x14) 42#define JMP(reg) \ 43 (((reg) << 6) | (0x0d << 26) | 0x20) 44 45#elif __nios2_arch__ == 1 46#define MOVHI(reg,imm16) \ 47 (((reg) << 22) | ((imm16) << 6) | 0x34) 48#define ORI(reg,imm16) \ 49 (((reg) << 27) | ((reg) << 22) | ((imm16) << 6) | 0x14) 50#define JMP(reg) \ 51 (((reg) << 27) | (0x0d << 11) | 0x3a) 52 53#else 54#error "Unknown Nios II architecture level" 55#endif 56 57void 58__trampoline_setup (unsigned int *addr, void *fnptr, void *chainptr) 59{ 60 unsigned int fn = (unsigned int) fnptr; 61 unsigned int chain = (unsigned int) chainptr; 62 int i; 63 64 addr[0] = MOVHI (SC_REGNO, ((chain >> 16) & 0xffff)); 65 addr[1] = ORI (SC_REGNO, (chain & 0xffff)); 66 addr[2] = MOVHI (2, ((fn >> 16) & 0xffff)); 67 addr[3] = ORI (2, (fn & 0xffff)); 68 addr[4] = JMP (2); 69 70 /* Flush the caches. 71 See Example 9-4 in the Nios II Software Developer's Handbook. */ 72 for (i = 0; i < 5; i++) 73 asm volatile ("flushd 0(%0); flushi %0" :: "r"(addr + i) : "memory"); 74 asm volatile ("flushp" ::: "memory"); 75} 76