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