stable 重构文件结构

抽象出Machine Code

src/ccompiler/backend/riscv32/README.md

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+# 后端代码生成
+
+## riscv32i
+
+> 仿照ripes的syscall，实现了rv32-vm
+
+### syscall ecall 系统调用
+
+```c
+// ecall 系统调用函数实现
+#define ECALL_PNT_INT(num) \
+    ADDI(REG_A0, REG_X0, num), \
+    ADDI(REG_A7, REG_X0, 0x1), \
+    ECALL(),
+
+#define ECALL_PNT_STR(str) \
+    ADDI(REG_A0, REG_X0, str), \
+    ADDI(REG_A7, REG_X0, 0x4), \
+    ECALL(),
+
+#define ECALL_EXIT(errno) \
+    ADDI(REG_A0, REG_X0, errno), \
+    ADDI(REG_A7, REG_X0, 10), \
+    ECALL(),
+
+#define ECALL_SCAN_INT(int) \
+    ADDI(REG_A7, (1025 + 4)), \
+    ECALL(),
+
+#define ECALL_SCAN_STR(str) \
+    ADDI(REG_A0, REG_X0, str), \
+    ADDI(REG_A7, REG_X0, (1025 + 5)), \
+    ECALL(),
+
+// 函数声明
+void ecall_pnt_int(int num);
+void ecall_pnt_str(char *str);
+void ecall_exit(int errno);
+int ecall_scani();
+void ecall_scans(char *str);
+```