xinyangli
2824efad33
NJU-ProjectN/nemu eb63cf3568dbf4e0c3c6ef462e6ec685550fabbc Merge pull request #76 from rijuyuezhu/master
74 lines
2.4 KiB
C
74 lines
2.4 KiB
C
/***************************************************************************************
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* Copyright (c) 2014-2022 Zihao Yu, Nanjing University
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*
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* NEMU is licensed under Mulan PSL v2.
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* You can use this software according to the terms and conditions of the Mulan PSL v2.
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* You may obtain a copy of Mulan PSL v2 at:
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* http://license.coscl.org.cn/MulanPSL2
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*
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* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
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* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
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* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
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*
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* See the Mulan PSL v2 for more details.
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***************************************************************************************/
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#include "local-include/reg.h"
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#include <cpu/cpu.h>
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#include <cpu/ifetch.h>
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#include <cpu/decode.h>
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#define R(i) gpr(i)
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#define Mr vaddr_read
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#define Mw vaddr_write
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enum {
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TYPE_I, TYPE_U,
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TYPE_N, // none
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};
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#define src1R() do { *src1 = R(rs); } while (0)
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#define src2R() do { *src2 = R(rt); } while (0)
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#define immI() do { *imm = SEXT(BITS(i, 15, 0), 16); } while(0)
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#define immU() do { *imm = BITS(i, 15, 0); } while(0)
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static void decode_operand(Decode *s, int *rd, word_t *src1, word_t *src2, word_t *imm, int type) {
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uint32_t i = s->isa.inst.val;
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int rt = BITS(i, 20, 16);
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int rs = BITS(i, 25, 21);
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*rd = (type == TYPE_U || type == TYPE_I) ? rt : BITS(i, 15, 11);
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switch (type) {
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case TYPE_I: src1R(); immI(); break;
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case TYPE_U: src1R(); immU(); break;
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}
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}
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static int decode_exec(Decode *s) {
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int rd = 0;
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word_t src1 = 0, src2 = 0, imm = 0;
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s->dnpc = s->snpc;
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#define INSTPAT_INST(s) ((s)->isa.inst.val)
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#define INSTPAT_MATCH(s, name, type, ... /* execute body */ ) { \
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decode_operand(s, &rd, &src1, &src2, &imm, concat(TYPE_, type)); \
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__VA_ARGS__ ; \
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}
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INSTPAT_START();
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INSTPAT("001111 ????? ????? ????? ????? ??????", lui , U, R(rd) = imm << 16);
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INSTPAT("100011 ????? ????? ????? ????? ??????", lw , I, R(rd) = Mr(src1 + imm, 4));
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INSTPAT("101011 ????? ????? ????? ????? ??????", sw , I, Mw(src1 + imm, 4, R(rd)));
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INSTPAT("011100 ????? ????? ????? ????? 111111", sdbbp , N, NEMUTRAP(s->pc, R(2))); // R(2) is $v0;
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INSTPAT("?????? ????? ????? ????? ????? ??????", inv , N, INV(s->pc));
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INSTPAT_END();
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R(0) = 0; // reset $zero to 0
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return 0;
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}
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int isa_exec_once(Decode *s) {
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s->isa.inst.val = inst_fetch(&s->snpc, 4);
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return decode_exec(s);
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}
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