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- Types.h：定宽类型、TypeTag、饱和四则的 @brief/@param/@return - Op.h：Op 枚举冻结约束、OpFormat/OpClass、OpDef/kOpDefs 表、三个查询函数 - Instr.h：指令字布局、pack/拆字段、按形态 enc_* 系列 - Encode.h/.cpp：Decoded 字段语义、encode/decode/disasm 契约
93 lines
2.6 KiB
C++
93 lines
2.6 KiB
C++
/**
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* @file Encode.cpp
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* @brief 指令编解码与反汇编实现
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* @author
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* @date 2026-08-19
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*/
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#include "isa/Encode.h"
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#include <cstdio>
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namespace isa {
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/**
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* @brief 编码：字段视图打包成一条 32 位指令字。
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* @param d 解码后的字段视图
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* @return 打包后的指令字；满足 encode(decode(w)) == w
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*/
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Instr encode(Decoded d) {
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return pack(d.op, d.rd, d.a, d.b);
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}
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/**
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* @brief 解码：指令字拆成字段视图。
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* @param w 32 位指令字
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* @return 各字段视图
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*/
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Decoded decode(Instr w) {
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Decoded d;
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d.op = op(w);
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d.rd = rd(w);
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d.a = a(w);
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d.b = b(w);
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return d;
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}
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/**
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* @brief 反汇编一条指令为一行文本。
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* @param w 指令字
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* @param out 输出缓冲
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* @param cap 缓冲容量（含 '\0'）；cap==0 时直接返回、不写 out
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* @details 按操作数形态表驱动输出，文本与 Doc/isa/指令与映像.md 一致；
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* 未知操作码输出 `??? 0x<w>`。
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*/
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void disasm(Instr w, char* out, size_t cap) {
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if (cap == 0) {
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return;
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}
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out[0] = '\0';
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const Op o = op(w);
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const int idx = static_cast<int>(o);
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if (idx < 0 || idx >= kOpCount) {
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snprintf(out, cap, "??? 0x%08x", static_cast<unsigned>(w));
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return;
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}
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const char* m = mnemonic(o);
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// 表驱动：按操作数形态输出（文本与 Doc/isa/指令与映像.md 一致）
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switch (format(o)) {
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case OpFormat::RR:
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snprintf(out, cap, "%s r%u, r%u", m,
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static_cast<unsigned>(rd(w)), static_cast<unsigned>(a(w)));
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break;
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case OpFormat::RRR:
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snprintf(out, cap, "%s r%u, r%u, r%u", m,
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static_cast<unsigned>(rd(w)), static_cast<unsigned>(a(w)),
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static_cast<unsigned>(b(w)));
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break;
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case OpFormat::IMM:
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case OpFormat::SLOT:
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snprintf(out, cap, "%s r%u, %u", m,
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static_cast<unsigned>(rd(w)), static_cast<unsigned>(imm16(w)));
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break;
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case OpFormat::JMP:
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snprintf(out, cap, "%s %+d", m, static_cast<int>(off16(w)));
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break;
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case OpFormat::JC:
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snprintf(out, cap, "%s r%u, %+d", m,
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static_cast<unsigned>(rd(w)), static_cast<int>(off16(w)));
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break;
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case OpFormat::CALL:
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case OpFormat::CAL:
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snprintf(out, cap, "%s %u", m, static_cast<unsigned>(imm16(w)));
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break;
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case OpFormat::NONE:
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snprintf(out, cap, "%s", m);
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break;
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}
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}
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} // namespace isa
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